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GEOL6350-Advanced Structural Geology - Day6 PM 03-05-2022
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00:19 mm hmm. Okay, we're going go on and talk about our last
01:39 , strike slip structures. Strike slip . So in in terms of different
01:55 of structures, we're going to talk strike slip tectonics, both where we
01:59 pure strike slip and where we have slip with an element of convergence or
02:05 element of, of divergence. so a strike slip fault is any
02:19 in which movement of the fault blocks primarily parallel to the strike of the
02:24 in terms of stress is sigma, is horizontal inclined to 30 degrees,
02:31 Sigma three is also a horizontal inclined 60° to the Fault. So this
02:37 this is different than um normal reverse where one of the stresses was always
02:46 to and perpendicular to the strike of fault. Now the sigma one sigma
02:51 are both inclined to the falls, that false refer It's a general
02:58 It can be any scale and we , we'll talk about both right lateral
03:04 left lateral strike slip faults when the sense of displacement is to the right
03:11 to the left. Wrench falls are scale. Deep rooted vertical regional crustal
03:18 faults were transparent. Also referred to transparent falls, transform falls are the
03:26 bounding strikes that falls that cut through entire length this year. Transfer faults
03:33 informally used to refer to applique could connect and transfer slip between adjacent
03:39 overlapping. Strike slip segments, tear accommodate differential displacement or a position of
03:48 faults in full thrust structures or for matter in normal fault structures. So
03:55 slip structures are additional structures besides faults echelon folds that form in response to
04:04 strike slip faulting or sheer. So strikes that falls sigma one is
04:15 Sigma three is horizontal. Sigod two vertical and the stresses sigma one sigma
04:25 are inclined to the strike of the . In normal faults, The Sigma
04:32 was always perpendicular to the fall With faults. Sigma three was also perpendicular
04:40 the strike of the faults. Now Sigma three and Sigma one are inclined
04:44 the strike of the faults. left, lateral and right lateral,
04:53 , lateral or sinister or strike slip is one where when you stand on
04:59 side of the falls and look across . The block across the fault is
05:04 to the left and it's also called role. Right lateral or dextrose
05:10 That falls are ones where the adjacent has moved to the right, the
05:17 shear is to the right. Mhm. Okay, earthquake focal plane
05:27 or beach balls. They identify the of earthquake from the first motions that
05:35 recorded on seismometers, their lower hemisphere of The pressure quadrants, CP or
05:45 one In the tensile quadrants, the . or Sigma three. The first
05:51 at a sizing station, The nodal divide the hemisphere into four quadrants and
06:01 nodal planes defined two possible orientations by sigma one always lies in the white
06:10 quadrant in Sigma three always lies in black colored quarter. So you know
06:20 plane solution like this sigma, one oriented here and you can have either
06:26 right lateral strike slip fault or a lateral strike slip fault. These show
06:40 mechanisms for different types of faults. types of earthquakes Here are the focal
06:47 for a normal fault. Signal. would be vertical in the middle of
06:52 white quadrant here and in cross section here these two nodal planes would represent
07:00 normal falsehood disorientation and in this orientation sigma one being vertical with a thrust
07:09 . The focal plane mechanism looks like with the black quadrant in the middle
07:14 here these two nodal plans Would represent faults either in this orientation with a
07:22 signal one For this orientation also with sigma, one with dr slip
07:29 The topic will be interesting, mainly quadrants look like this, where the
07:34 planes can define either right lateral strike faults or left lateral strike slip
07:42 And in this, in the cross across this salt. So looking at
07:48 cross section of disorientation, one of convention is that this symbol represents the
07:56 of an arrowhead that's pointed towards This symbol represents the tale of an
08:01 that's going away from you. So a right lateral strike slip fault like
08:07 . The symbols would look like this indicate a right lateral strike slip fault
08:18 of course um the the planes are always vertical and horizontal. So you
08:26 these inclinations of the focal mechanism Here we again, we've got the
08:33 that falls with vertical falls in this , disorientation or disorientation With the signal
08:41 or P. axis bisecting the white here. With this solution, We
08:48 the single one horizontal bisecting the white here acting on a plane that's dipping
08:55 the southeast or a plane that's dipping to the southwest. And and that
09:04 you this kind of block diagram where default is dipping steeply to the southeast
09:13 fault. And that would be this fault with a reverse sense of displacement
09:19 a decline normal fault. Um The quadrant is is in this orientation more
09:26 less straight up and down, indicating , One is in this orientation with
09:31 fault in even this orientation to be the northeast, or this orientation dipping
09:37 the southwest. So this kind of plane mechanism with this red fall would
09:45 this kind of red normal fall should of fall represented by the red line
09:51 dipping in the Northeast with a two sense of displacement. And the important
10:02 to remember here is that these are hemisphere projections. So when we're looking
10:06 a focal playing solution like this, at a lower hemisphere projection where this
10:14 plane represents this red plane in the hemisphere protection. Right? All
10:26 The different types of scales of strike faults. Um The biggest scale are
10:32 transform plate boundaries between spreading centers of plates. So these are um strike
10:40 tectonic plate boundaries and Matthew they look this where you have a mid ocean
10:47 spreading center here, mid ocean ridge center here. And in between this
10:53 is moving to the left, this is moving to the right. And
10:57 you have a left lateral sense of along this active transform fine once in
11:05 act and transform is limited to um between the spreading centers. Once you
11:12 beyond the spreading centers, a fracture that no longer has any active shear
11:18 it. And some of the most well studied are off the west coast
11:26 California Oregon. Mhm. Where you these transformed zones separating the juan de
11:35 plate from the pacific plate here and only active between the spreading centers beyond
11:46 spreading centers. You have a fracture but no actual strike slip displacement
11:57 Okay, so these transform plate boundaries actual tectonic plates occur all over the
12:04 , Who san Andreas is the most famous most well known when you get
12:11 into Alaska, you get the Denali fault and the fairweather queen charlotte islands
12:20 . You have several transform faults in caribbean. There are lots of micro
12:25 in more detail in order shown here and in south America, the el
12:30 transform fault and then multiple other transform all along the globe, wherever you
12:37 different plates converging. Another well well well known one is the Alpine fault
12:45 that goes through the middle of New . Sure, so here we've zoomed
12:58 the san Andreas fault transform fault between pacific plate and the north american plate
13:04 , pacific plate is moving towards the . Well the north american plate is
13:10 towards the south relative to the pacific and it gives you this right lateral
13:15 of displacement along the san Andreas fault you get down towards L.
13:21 And san Diego. The SAn Andreas breaks up into several different displays with
13:26 individual different names in New Zealand you the Alpine transform fault to the
13:35 right lateral transform fault between the Australian here in the pacific plate here and
13:43 again is a single transform fault for of its length and then it breaks
13:48 into several different displays when you get the north end of, why don't
13:52 stay on now? The SAn Andreas is subdivided into several different zones.
14:09 have what are called locks segments shown the green here and the green here
14:17 this parkfield section along here which is locked and then in between here you
14:28 this cole lingus segment which is actually . So this is this segment is
14:35 moving. Whereas these segments here and are block, they're not moving and
14:43 thought that strain is just building up this segment in this segment and will
14:50 fail when they give you a large of earthquake. It takes up all
14:55 creeping strain that's occurring along this segment the fault. Okay, now we
15:06 have transformer transfer faults between offsets and or normal falls. So for
15:14 here in the Appalachians, we have thrust here and a thrust here and
15:20 we have these strike slip falls bounding thrust sheet that transfers the displacement um
15:28 this sheet out to the street. would be a lateral ramp where we
15:37 a front ramp here, the front here, a flat stepping up to
15:41 ramp to a flat here and then this lateral ramp, we would have
15:46 right lateral sense of displacement along the fault between two segments of the thrust
15:56 . Right, Tara Falls are a different. They accommodate differential displacement between
16:02 adjacent structures. Oh, so here have a series of attacks reforms
16:08 I have a second series of intact . There's greater shortening along here.
16:14 along here and there's a strike slip in between called a tear fault that
16:20 that differential displacement between this block and this block in the background.
16:31 Okay, so identifying strike slip tectonics structure that movement. So we're looking
16:38 surface displacements related to seismic events and focal mechanisms that define strike slip
16:47 We can also define the sense of of the magnitude of the displacement by
16:55 . D'amore phycor fizzy a graphic features of markers, separation of piercing points
17:02 some linear feature intersects a strike slip . Okay, They are also identified
17:11 horizontal switching sides on the fault surfaces . They can also be identified by
17:21 faults with opposite sensitive separation. And space problems. And to the interpretations
17:28 often indication of a strike slip Strike slip deformation. Okay, now
17:37 get different types of strike slip We get restraining bends and releasing bends
17:43 the faults converged where they diverge. we get transcripts of structures where there's
17:50 an element of convergence along the strike fault that gives us a positive flower
17:56 and negative flower structures. Worry however component to movement along the fault.
18:08 these are examples of restraining and releasing . So here I've got a right
18:14 strike slip fault. We're in this segment, it's moving to the
18:19 This segment is to the left and there's a step over, you get
18:26 pull apart basin or a structural low these two plates are actually pulling apart
18:33 lee if you have right slip displacement and a less slip displacement here,
18:41 between where there's this step over these blocks are going to converge and give
18:47 reverse faults or structural highs or an or some kind of pop up structure
18:52 these two different strikes, the blocks on each other. So these are
18:58 releasing bands and these are called restraining . There's a block diagram showing an
19:08 where I have a right lateral strike fault here is stepping over to the
19:13 and creating a releasing ban where there's sense of extension between this block in
19:19 block. In addition to the strike , hear that strike slip fault has
19:24 restraining band where it steps over to left. And now I have a
19:29 component of stress and strain across this of the fault that's going to give
19:35 to reverse faults and folds and anna in this area, the strength look
19:46 . So, here's a here's a model showing a right lateral restraint.
19:52 here we're looking at the surface of model with increasing amounts of displacement.
19:58 inset on the upper left shows a block diagram of the the deformation mechanism
20:05 underlies the clay on here. So block moves to the right. This
20:11 moves to the left in between the blocks converge and give you this restraining
20:18 . So, here's what it looks with progressive deformation with a small amount
20:22 displacement along here, The faults have broken through yet. And you have
20:28 little bit of an uplift here in middle with increasing amounts of displacement from
20:33 . The only way to here. the strike slip faults breakthrough cover rocks
20:39 where you have this restrained band, get a large pop up structure shown
20:44 the elevated concerts here. Right? example of that is the transverse ranges
20:56 southern California. Down by the A. Basin, you're the san
21:01 fault with the right lateral sense of goes through a a left bend that
21:10 the strikes of displacement to add a of component along this area. And
21:17 gives rise to the whole transverse ranges . Yeah, reverse faults like the
21:24 Madre fault here. Right, so a series of focal mechanisms showing strikes
21:37 tectonics, strikes of displacement and a restraining Bennett along through here. So
21:48 the faults here here on the long fault here. The way your fault
21:56 . The focal mechanisms indicate of strike tectonics when you get up here towards
22:03 transverse ranges and the Northridge fault. , all the focal mechanisms educate thrust
22:11 on these faults when you go offshore into the santa Barbara Island and the
22:17 barbara falls up here. Get flip, display spending down. So
22:21 we have. Mhm. This plate this way, this plate moving this
22:28 a series of strike slip faults that that displacement and a series of reverse
22:34 up here. Where do you have convergence of those two different places.
22:47 , here's an example also from southern , the san Andreas fault, what's
22:52 the Coyote Creek thought restraining bend. here the north american plate is moving
22:59 the southeast, the pacific plate is to the northwest along here and
23:06 I have relatively simple strikes, flip a right lateral sense of displacement here
23:12 the false step over in this direction I have a restraining band with a
23:17 high a lot of folds and inclines sink line pairs developed in that restraining
23:24 as a result of the compression in northwest southeast direction. Here's an example
23:36 a left lateral restraint than front, series of strikes that falls in Thailand
23:43 , this major plate is moving to left. This major play is moving
23:48 the right where the main fault make right step over here, I got
23:54 series of reverse faults and duplexes formed the compression form between these two
24:01 where they make this right lateral I should say not right lateral
24:08 it's a left lateral fault with a step. So here's a clay model
24:18 a restraining band with a left lateral of displacement. Again, we're looking
24:23 the top of claim layer of clay here that's layered on top of this
24:30 basement block. And now we have left sense of displacement on this block
24:36 to this block here with a a in the middle here that's gonna cause
24:42 between these two. And so these the results in the clay model.
24:48 increasing amounts of displacement. You can one fault coming through here, a
24:55 here and one fault coming through here increasing amounts of displacement. He did
25:01 little below in here until ultimately you this very significant low represented by the
25:09 colors here as these two blocks diverge this releasing Denmark. Okay, the
25:22 sea is an example of a right releasing better here in in southern California
25:29 to Mexico. North american plate is this way, pacific plate is moving
25:34 way san Andreas fault comes up steps to the right and then continues
25:40 here. And what makes that step , being pulled apart to create a
25:48 low in this case, built in the salt and see surely we would
25:55 gone normal faults developing and of course ground instructors development here, ultimately evolving
26:07 this Salton sea continual low that fills the below in this releasing Ben.
26:17 Dead sea is another example of a bend between the Arabian place here and
26:25 mediterranean plate here left lateral sense of along the through going fault and where
26:33 fault makes a left step here, get a topographic and structural low that
26:38 the topographic expression or location from the sea and then along the fault adjacent
26:49 the fault and you have all And inclines inclines peers representing an echelon
26:56 formed in response to this left lateral of displacement. Ah in California,
27:11 another example of a right lateral releasing here. The north american plate is
27:16 to the southeast pacific plate is moving the northwest here and and here you
27:26 mm hmm. Through going right lateral where the faults make this step over
27:32 this segment to this segment, get topographic low that forms the location for
27:40 a topographic wait here. The mesquite . Okay, here's another example of
27:53 right lateral releasing band in this case the hope fault for the Alpine fault
27:59 in New Zealand before comes along here a right lateral sensitive placement. This
28:08 is moving to them right this plate moving to the left towards the southwest
28:14 it makes a step over, you a whole series of normal faults in
28:19 . Accommodating the extension between this block this way in this box going that
28:25 and in addition to these normal you develop a topographic glow with a
28:30 here in the middle. Okay, an example of a right lateral releasing
28:43 from the san Jacinto fault in This this is inclined so north is
28:51 this way. The north american plate moving this way to the southeast,
28:55 pacific place moving this way to the , we have a through going right
29:01 strike slip fault here and right lateral slip fault here where this steps over
29:07 here, you get a series of faults allowing the extension. Accommodating the
29:14 between this part. Moving this way this park. Moving down.
29:25 okay, sure. We were looking a strained lips showing the orientation of
29:32 different structures that we get with strike deformation. So the way the strain
29:37 is oriented with the long axis. way it is giving me the right
29:43 sense of displacement in Matthew. And yes, where the strain ellipse is
29:53 in this way. In this way normal faults with disorientation. I'm inclined
29:59 the since the overall sense of displacement the strike slip fault in this orientation
30:06 have compression. I'll get fools and faults developing. And then within the
30:13 , within the strain ellipse itself. will be two lines of no finite
30:21 to separate the extension all quadrants from normal from the commercial boxers with progressive
30:37 . That strain ellipse is going to shape and elongate. So we'll start
30:42 with low strain with the increasing we get this much, much greater
30:49 of limbs in the orientation of these is going to rotate with increasing
30:57 So as I increase the strain from to here, these fold axes are
31:04 to become more and more inclined, and more sub parallel to the sense
31:09 strike slip displacement. The normal faults are going to become more and more
31:15 orthogonal to the sense of strike slip , so with progressive deformation with increasing
31:23 , the orientation of the pitfalls and falls, thrust and normal thoughts and
31:29 will change as a function of the . So, here's an example of
31:39 in a claimed model again. So looking down on the top of a
31:45 model with a through going right lateral slip faults underlying the clay model here
31:53 a small sense of with a small of displacement, we develop these strain
32:02 , they're only slightly elongated, some growing falls here and here. And
32:10 octagonal structure is developed in this orientation a national unfolds with increasing displacement,
32:17 strain ellipse has become more deformed, distorted. Mhm. And a clinical
32:23 are offset in the initial on Breakthrough here to form a through going
32:31 segments with Lots of 2nd order extension bands and congressional bands. So here's
32:45 analogous structure with a left lateral right . I'm looking down at the top
32:51 a clay model again, with a of displacement increasing from here to here
32:57 in this case it's a left lateral of displacement with small displacements, you
33:03 slight offset of the circles to become ellipses with only a little bit of
33:08 investigation and shortening with the increasing displacement vault breaks through to form multiple segments
33:17 the overlying cover here and the string lips has become increasingly distorted. Well
33:24 with the increasing displacement. Now, features that are associated with strikes,
33:34 faulting are called Riedel shears. So here's the overall um impose strike slip
33:49 with that left lateral fault. That I have a signal one inclined in
33:53 orientation To the strikes of fall and to the strikes of fall and the
34:00 three. And extension Extreme strain oriented 60° to the normal fault here.
34:08 in response to these senses of compression extension, we can get other anesthetic
34:15 synthetic shares. We can get synthetic oriented like this at an oblique angle
34:21 the overall sheer. And we can these anti aesthetic sensitive displacement here.
34:28 if you think of these as convenient both. These are confident false.
34:33 ? With a real chair here in ant, what's called an anti Riedel
34:38 here, this block moving in this , in response to the compression in
34:45 direction and the extension in this So we get the selling regal shares
34:54 our shares formed first at an acute to the main hall fault. Was
34:59 synthetic sense of displacement. And then get these are crimes or anti Redl
35:07 formed as conjugal to these regional shares increasing amounts of displacement. In in
35:15 , we should get these P and . Prime shares as well, synthetic
35:21 synthetic to the R. And Primes. But in um hmm real
35:28 , we rarely see those. So often see these these read these Redl
35:35 in this orientation. And in this we rarely actually see these P.
35:39 P. Prime shares in this orientation disorientation. Here's an example from a
35:49 model with the clay layer here, basement blocks or boards here with a
35:58 lateral sense of displacement. In that in that overlying Clague model, we
36:06 these synthetics years developed representing the Riedel . And then we get these antisemitic
36:14 developed called the art crimes for the Riedel shears in three D. This
36:26 what these Riedel shears look like. here's my my vision blocks here with
36:32 overburden here by through going strike slip here that serves as the locus of
36:39 overlying Riedel shears. In the overlying , we developed these Redl shares with
36:45 sense of displacement, synthetic to the lateral sense of displacement in the
36:51 which are in the shallow levels. are inclined to the overall census year
36:58 you approach the underlying basement Here, rotate to become parallel to the underlying
37:05 here. So you have this kind thing. Kill acquittal geometry of the
37:11 shears. Okay, so here are of Riedel shears adjacent to the SAn
37:25 fault in Southern California. So here's SAn Andreas fault with the right lateral
37:30 of displacement. And then in board the SAn Andreas fault. You have
37:35 these minor faults with synthetic senses of , right lateral senses of displacement.
37:42 all these guys. So these guys represent Riedel shears sympathetic to the main
37:48 Andreas fault going through here right we also get the initial on folds
38:00 to strike slip faulting as that strain evolves get shortening in this direction,
38:08 folds and thrust faults in this Yeah. Ah In plan view,
38:16 looks like this. We're here. have a right lateral sense of displacement
38:21 then I get these and echelon folds at an acute angle to this right
38:28 sense of displacement analogous lee where I a left lateral sense of displacement.
38:36 can get these in Ashkelon folds overlying underlying basement drop, basement form inclined
38:43 about 30° to this overall sense of lateral displacement. So, and that's
38:52 unfolds like this. Tell me there's right lateral fault underlying the shallow rocks
39:00 . Here we are at the restaurant like this. It's telling me that
39:04 have a left lateral fault in the underlying the deformed probably rocks here.
39:14 , so here's an example of those clay models. Again, looking down
39:19 two different cleared clay box models, basement underlying this. The basement blocks
39:28 this have a right lateral sense of here. And you develop these in
39:33 folds in the overlying cover rocks. model, but with an opposite sense
39:38 displacement. Mm hmm. I'm No, it would have increased
39:44 So increased sense of displacement from here here. Now we start to get
39:50 Riedel shears breaking through the center and rocks offsetting the restaurant folds that formed
39:57 the earlier low strain stages. Mm . So, so here we have
40:13 example of right lateral sense of Here we have a left lateral sense
40:18 displacement with this right lateral sense of in the through going basement block.
40:26 , I get shortening in this orientation extension and elongation in this orientation parallel
40:33 the long axis of the strain of . That gives me these initial unfolds
40:39 normal faults forming in this orientation perpendicular the extension direction. With a left
40:47 sense of displacement, the orientation of extension and shortening flipped 90 degrees.
40:53 here with the left lateral sense of . This guy moving this way,
40:58 one moving this way through going fault the basement. Here, I get
41:03 overlying, an occasional falls form in to the shortening in this direction.
41:10 I can also get normal faults forming this orientation in response to this elongation
41:17 in this northwest southeast direction. okay, so here's an example of
41:29 unfolds in the Pleistocene beds along the san Andreas fault. So here's the
41:35 san. Andreas fault going through here then in the adjacent block here,
41:42 gonna get all these initial unfolds developed response to the right lateral sense of
41:48 along the SAn Andreas fault two. know, we can also get rotational
42:03 domino style folk blocks developed within um to these faults and within some of
42:13 stepovers last fall. So here we've the san Andreas fault moving this with
42:19 north american plate moving this way and gave you a fault with the pacific
42:25 moving this way and then in between two right lateral fault, we get
42:33 empathetic um domino style rotational fault blocks with senses of left lateral displacement with
42:42 displacement and increasing strain Between these two . These rotate in our in a
42:50 sense of accommodating the extension and strain between these two overall falls. So
43:04 are examples of um a positive flower and a negative flower structure. Positive
43:14 structure evolves where you have what's called , where you have strike slip plus
43:21 element of compression, negative flower developer, you have trans tension where
43:28 have a component of strike slip displacement extension along the fall. So these
43:37 positive flower structures are analogous to restraining in the system. These negative flower
43:44 are analogous to releasing bends in the slip system. And here's the type
43:57 of a positive flower structure. And was interpreted from seismic data and the
44:05 . The they have their coma basin southern Southern Oklahoma. We have a
44:11 box here that were interpreted to have right lateral sense of displacement here with
44:18 pop up structure here, we now that this is a detachment structure overlying
44:25 slip displacement along this system. oh, it's in fact a dip
44:32 to tax reform rather than a positive structure. Nevertheless, this serves as
44:41 as the model from what a positive structure should look like. He was
44:50 seismic image of a negative flower This example comes from Indonesia, where
44:58 have a strike slip system here with block moving towards me, this block
45:04 away from me. So in we have a left lateral sense of
45:09 where this comes up towards the shallow . It diverges and essentially forms a
45:14 ban. The results in this negative structure for the sediments here are collapsing
45:20 into the divergent, false in this . Here's another example of a negative
45:33 structure from Indonesia. The We have strike slip strand here, this strike
45:42 sand strand here. Oh, in case it's a it's a right lateral
45:47 with this side moving towards me this moving away from me and as that
45:54 increases these segments diverge and form a flower structure where the overlying sediments collapsed
46:01 that zone of diverging strain diverging strike motion. Okay, so here's a
46:12 diagram showing the conceptual model for mm hmm. Overall, we have
46:19 right lateral sense of displacement with this ductile block in between. In addition
46:27 the strikes of displacement, we impose compression and displacement across the, across
46:34 block, resulting in compression strain in box. In addition to the strike
46:41 displacement and that's going to result in or positive flower structure in this
46:52 Um Here's a here's another example of positive flower structure, transgressive structure,
47:03 lateral displacement. This spot moving this , this part moving this way.
47:08 . With a component of shortening a across there, resulting in the material
47:14 the middle being squeezed up to form international pop up folds In between the
47:20 major strike slip box. Here's an of a positive flower structure um from
47:37 this is from the Salton sea area southern California main going strikes of fault
47:45 in here and in between. We all these displays with reverse senses of
47:55 along here, causing the blocks here . Move up relative to the block
48:04 here. And what's what's interesting about one is that along this sense of
48:12 , we have reverse senses of displacement this sense of display and we have
48:18 normal sensitive displacement. So we have very complex flower structure here, combining
48:25 of shortening and extension within the same structure. Okay, and these examples
48:39 from the mecca hills area in um southern California along the san Andreas fault
48:46 . So, overall we have a lateral sense of displacement along the system
48:52 these flower structures developing along this part the following. So here's an example
49:04 how these things evolve here. We the uninformed state with the dash lines
49:12 we're through going. Strike slip faults going to form initially with the transgressive
49:21 . This block moved towards us. block moves away from us and the
49:25 in the middle are forced upward by professional component across here, giving this
49:30 of draped fold over the crest of structure with increasing displacement and deformation,
49:37 faults breakthrough to give you the reverse of offset that we see in the
49:45 the false here with with continued this block continues to move towards
49:53 These faults evolve, propagating up shallower the section with increasing amounts of
50:00 giving these overturned folds within the within overall flower structure. Okay, in
50:16 block diagram shows that it's it's impossible do. It dip slip restoration of
50:24 faults. So here's the deformed state strike slip faults bounding here and
50:32 if we try to do a two dip slip, balanced, massive reconstruction
50:36 this, these shell sediments are always than the thing is deeper in the
50:43 here. The results of these boxes restore state being pulled apart, creating
50:49 between the blocks here and along the here. So it's it's impossible did
50:56 do to the restoration along strike slip like this and the conversely, the
51:08 to balance this in a section can an indication of strike slip displacement rather
51:15 a dip slip displacement. Alright, associated with strike slip systems and related
51:27 traps. So here's your examples of echelon folds developing with increasing amounts of
51:36 lateral strike slip displacement. Here. the early stages, I get the
51:41 falls with real shears initially breaking through moral displacement with the increasing displacement.
51:51 phones are tightened and offset and ultimately real shares link up to form a
51:59 going fault here, offsetting the oh, the various santa clients informing
52:06 the early stages. Mhm. And see that in the san Joaquin basin
52:18 we have the san Andreas fault with right lateral sense of displacement here,
52:23 an adjacent to the san Andreas We have all these antique lines inclined
52:28 developed on here and along here that some of the, some of the
52:34 oil fields within the southern san Joaquin . Here's an example from the inglewood
52:45 fields in the L. A. . Main strike slip fault going through
52:51 in an incline trending here, an to the fall. Initially, this
52:57 in the early stages before it was through by default here and separates the
53:06 field into various different components separated by these different strikes footfalls. Okay,
53:20 here are examples of structures that may like positive flower structures where we have
53:28 of thrust fault blocks. This type structure would be a dip slip structure
53:34 resembles a positive flower structure here where have a triangle zone formed by detachment
53:41 here with all the dip slip, faulting in here. That's going to
53:45 us a structure that overall looks like positive little structure here. And um
53:54 we have inverted structures along the faults as this, where you have initial
54:00 , Listrik, normal faulting and growth here, then inverted by displacement.
54:06 going to give you a structure on that looks very similar to a positive
54:11 structure here. Okay, so now have examples of structures that superficially look
54:22 negative flower structures. So here we an extension of fault zone with trade
54:29 in normal faulting at the tips of through going normal falls, they're going
54:34 give you a set of structures superficially to a negative flower structure here.
54:42 , here, we have a holistic fault where the crystal collapsed and decline
54:46 the top of it. It's going give you a structure that superficially looks
54:51 a negative flower structure here right it's it's important to distinguish our current
55:07 from real offset on the other So here, I've got a block
55:13 of a normal fault with a dip census with a dip slip displacement along
55:20 and here in the purple, I an inclined bed, It's offset by
55:25 dip slip displacement. Now with the slip displacement one, the intersection of
55:32 Purple bed with the normal fault, going to have this apparent sense of
55:39 from here. If I look at plane down here, if I rode
55:44 block down to this level, I fact have normal displacement along a normal
55:51 here. The fall traits that the strikes here. The dip at the
55:58 in the near surface is here but purple bed is going to give me
56:02 apparent left lateral separation around the So when looking at horizontal separations like
56:11 in Matthew, it's important to evaluate type of thought you're looking at.
56:16 you really looking at a strike slip or are you looking at a normal
56:21 fault? That would give you the sense of separation due to dip slip
56:26 rather than strike slip deformation. Right. So considerations and interpreting strike
56:38 structures. Strike slip structures can commonly confused with other types of structures before
56:47 the orientations of secondary structures to infer slip, I'll make sure you
56:51 the relative timing of the structures. for positive events for strikes that consists
56:59 thickness and fishies, changes and fault That need to be confirmed in three
57:06 And never interpret a flower structure on single two d. seismic section
57:17 Okay, so here's a class exercise have in the handouts, We're looking
57:24 2019 rich crest earthquakes. The SAn formed by the SAn Andreas system going
57:31 all through here and then we have series of strikes or have a series
57:37 faults here in here with the senses offset defined by the focal mechanisms here
57:44 here. Two. Given these focal , what is the sense of displacement
57:51 the red fault? And what is sense of displacement on the blue
57:58 Remember that in these focal mechanism beach Signal one intersects the white axis here
58:06 here. And you can use that get the sense of displacement along these
58:10 and blue falls. So go ahead look at those and when you're ready
58:21 speak up and let me know what think. This is the displacement are
58:25 these two faults. The red fort right lateral, right, the blue
62:36 is left lateral. Yeah, Right. Good. Thank you
62:43 Okay, so with this focal mechanism um the P access or the signal
62:50 axis is oriented and disorientation and that's to give you a right lateral sense
62:55 displacement along the red faults here. this nodal plane in the focal mechanism
63:02 equals this set of red falls here the blue system here. The P
63:11 or the signal one compression. All is going to bisect the white segment
63:17 and give you a left lateral sense displacement along this nodal plane here representing
63:23 left lateral displacement along this blue fault through here. Yeah, so very
63:30 . Um comments your questions on Can you maybe explain it in a
63:39 way? Because I don't really, can't picture really understand how to tell
63:45 difference between the right and left True. Okay, so mm
64:00 I used page H. So if go to page eight despite age,
64:09 the way he's going away from you towards you and especially if you're in
64:15 orient the beach ball towards the strike the fault. So you see it's
64:21 of for the literature room. The is going towards the right along the
64:26 on the floor and for the left , The Blue one is going towards
64:32 left. So I use this to of see how the rotation was for
64:38 fault. Yes. So here we're at the focal mechanisms for the
64:48 The black is where we have the component with sigma three, the whitest
64:53 we have the compression component or sigma and Sigma one in this orientation,
64:59 give you a right lateral sense of along a fault in this orientation and
65:05 left lateral sense of displacement. A of fault in this orientation. Ouch
65:14 , that makes more sense to me . Okay, so coming back to
65:31 exercise figure. Um the vocal mechanism here tells me that I've got to
65:39 one oriented in this orientation parallel to era. And it could represent either
65:45 left lateral strike slip fault here or right lateral strike slip fault here.
65:52 right lateral strikes that thought parallels this on the ground. There's no fault
65:59 this orientation. So this focal mechanism telling me that I have a right
66:04 sense of displacement on the red faults analogous lee here with the blue
66:12 The focal mechanism is telling me I of maximum compressive stress in this
66:19 acting on a fault in this orientation in this orientation. If it's this
66:25 , I have a left lateral sense strike slip. If it's this
66:29 I have a right lateral sense of slip. Mhm. On the
66:33 I only have one fault in this . And so the focal mechanism is
66:39 me I have left lateral strike slip this blue fall down here on the
66:48 . So would the on the blue ? Mm hmm. The way you
66:56 at it is the left, is smaller one on the top. The
67:04 is the smaller one on the So that one's on the left
67:08 And then the longer blue line is right side. Um So the the
67:18 blue line here is the is the fault and it's parallel to this nodal
67:27 . And so the normal plain solution telling you that this has a left
67:32 sense of displacement along it parallel to nodal plane. Okay, I think
67:39 understand now. Okay. I'm not that answered your questions so mm
67:47 Right. Let me know if you more questions. Mhm. Right.
67:55 . I think it's Macd Ennis pointed . If you go back to those
67:59 couple of slides with the different block , it will help clarify how
68:05 how this comes together. The important is that the nodal solutions given the
68:14 of the maximum compressive stress and then compare that stress to whatever falls you
68:22 on the ground. And that gives gives you the sense of displacement along
68:27 faults. Okay, so let's let's on to this one. Here's a
68:42 of an echelon fold overlying a through basement fall below the government's here.
68:49 what is the sense of displacement of basement phone underlying these initial unfolds?
69:11 looking at the orientation of the actual . This is a light.
69:19 Yes, correct. It is a lateral system shoulder. Do you long
69:25 of the full. It gives you long axis of the strain of
69:32 And so with the strain ellipse oriented this orientation. Um That gives you
69:38 right lateral sense of displacement on the the whole system and on the underlying
69:43 block two. These are national on with this inclination or with this strike
69:52 you a right lateral sense of How about here if you were looking
70:01 a All right, the map of in Iraq, the red lines represent
70:08 going strike slip faults thing. Green represent an octagonal structures oil bearing an
70:17 structures across here show me what's given this inclination of the force to
70:26 through going fault? What's the sense displacement on the through growing forward from
70:31 underlying felt? So, if the , if this image is fluent in
73:33 direction and the oil bearing structures are the northwest and we have shortening in
73:43 southwest direction, I will say this the first natural. Yes, exactly
73:52 . Yeah. Good. Um so system of initial unfolds is is exactly
74:07 to what we saw in this except they're inclined in the other
74:15 So it's as if the folds are in this orientation. In giving you
74:20 left lateral sense of displacement. this inclination of the National unfolds in
74:28 is towards the top of the map incarnation of the in a climate
74:34 Just telling you that you have a lateral sense of displacement. Yeah,
74:39 hmm. Go back to, Can just help me with finding the direction
74:47 the previous example, You don't I understand the arab spring. The second
74:54 . Um This example. Mhm. me let me go back to some
75:04 the sandbox examples. So, with , with this sand bosque example,
75:24 have a right lateral sense of displacement the underlying block? And then all
75:29 in echelon folds formed at this orientation to the sense of displacement of the
75:35 blocks. So this would be what saw in the first example. And
76:00 in here we're seeing both right lateral a left lateral system. And here
76:07 in ashkelon folds are formed at this to the to the overall offset.
76:14 this comes from the orientation of the ellipse here so that the strain ellipse
76:22 always extended. Um mm hmm. always extended and in me, small
76:31 to the overall census year. So a sense of displacement like this,
76:36 will get forward in in this And that would represent my right lateral
76:42 of displacement here. If I have left layer of sense of displacement.
76:53 a left lateral sense of displacement Um My folds are going to be
76:57 at this orientation to the overall sense displaced families. Thank you,
77:11 Okay. Um and that's that's also by the strain ellipses here. Where
77:25 a sense of displacement like this, strain lips becomes more and more elongated
77:32 hmm. Towards the sense of And the fold axes are going to
77:37 in this orientation relative to the sense sheer. If I flip this,
77:43 I have the blood federal sense of . The strain of lips will be
77:48 At 90° to this? And the actions will be at this of the
77:53 to lower right orientations. Can you slide isn't in our slide then.
78:01 you send us this one please? it really it helps me to understand
78:08 better. Glad to do that. . Okay. Any other comments or
78:24 for this this section? Think To summarize and wrap up this
78:56 The strike slip fault is any fault which the movement of the boxes primarily
79:01 to the strike of the fault. it refers defaults at all scales right
79:08 is where the block block opposite what standing on, moves to the right
79:15 left lateral arsonist role is where that moves to the left. Wrench falls
79:22 large scale deep rooted vertical regional crustal falls, or also called trans current
79:30 , transform faults are the strikes that that cut through the atmosphere separating different
79:37 centers. Transfer faults for two oblique that connects and transfer slip between adjacent
79:45 overlapping strike slip faults. Tara Falls strike slip faults that accommodate differential
79:53 The position of thrust or normal I mean, these are the their
79:59 and lateral ramps. Strike slip structures general are things like the initial unfolds
80:07 form in response to large scale strike faulting or sheer. So these would
80:12 the restaurant folds and the horse and that formed in the stepovers between different
80:19 slip segments. Restraining bands or where get congressional structures full and thrust from
80:27 of the strike slips strands releasing bends where you get Colbert basing in Gros
80:33 from separation of the strike slip trance presage structures are things like positive
80:41 structures where you have a component of . In addition to the strike slip
80:47 , trans intentional structures are ones where have negative flower structures or extension.
80:53 addition to the strike slip deformation, strike slip structures can commonly be confused
81:02 other types of structures. Before you the orientations of secondary structures to infer
81:09 slip, make sure you know the , the relative timing of those different
81:16 that and then the focal playing mechanisms beach balls are shown here in the
81:25 thing to remember here is that the quadrant represents the initial compression first motion
81:32 gives you the orientation of sigma one wow, mm hmm. That gives
81:41 these nodal planes, disorientation or So the speech bubble solution Um with
81:49 one here can be represented by right strikes, footfalls here or a left
81:57 strike slip faults here and you have relate. Yes, theoretical nodal planes
82:05 the actual geology. To see whether is acting on a left lateral strikes
82:11 falls or a right lateral strike slip . What does the P. Beside
82:17 sigma one. Stand for pressure. it's synonymous. It means the same
82:31 as signal one it means the P professional component or the ah congressional opponent
82:40 . First acting on the all the default plans and then these other
82:51 mechanisms give you the orientations for thrust where your white segment here would be
83:01 by a congressional access in this And your normal false solutions here where
83:07 white clutter here would be intercepted by So vertical signal one plunging into the
83:14 of the section. Right, identifying slip components strikes the tectonics, you
83:30 identify by looking at service displacements related seismic events. The focal mechanisms offset
83:37 geum or phycor initial on or fizzy features like the initial unfolds, separation
83:45 markers like like different fishies, offset of piercing points. Um Some
83:53 slick insides on the faults themselves. things like this on the actual fault
83:59 are you that the motion was horizontal to the plane of the fall.
84:06 all these things are indicators of strike tectonics as opposed to slip tectonics.
84:18 so I will send you that additional . Um Well we'll take a break
84:24 and then do a segment on review the final exam. So let's
84:33 So it's it's it's 2 20. don't we resume in about 10 minutes
84:39 2:30 and I'll go through the review for the final exam. Okay so
85:10 go through a number of slides. will be the final review for what
85:13 be on the final exam. So . final exam will cover everything from
85:25 heels, two strikes sub structures, false real salt structures full of thrust
85:32 , all the different things we talked there and strike slip structures And it
85:37 represent 60% of the final grade. will be the same format as the
85:45 . Um It'll be a virtual online . I'll send it to you at
85:49 beginning of this, beginning of the and have you email it back to
85:54 when you're done. There are three allowed for that on the schedule.
85:59 don't think it'll take that long but have a lot of time to complete
86:04 . It'll be 30 years. So answer questions similar to the midterm
86:18 Okay damn it. Okay so the thing on the exam will be the
86:24 fault capacity and and that will um controls the fault dependent column hiding and
86:38 is different than the fault dependent Um default dependent com height may or
86:44 not be equal to the whole fault closure, maybe less than the full
86:50 closure. And this will be what talked about with the difference between total
86:56 and the column heights. Total column . Mhm. So um the total
87:08 we talked about represents the difference between crest and the ultimate spill point.
87:14 total column height represents the difference between crest and the oil water contact of
87:20 gas water contact. Similarly the fault closure represents the difference between the at
87:30 point, the highest point where the cuts, cuts the structure and the
87:35 point here. The fault in calm height goes from that same point
87:41 the fault hits the structure and now goes just to the oil water contact
87:46 the gas water content. So the dependent com height in the fall dependent
87:52 are not necessarily the same in in . That false dependent closure goes from
88:06 first contour that kisses the fall Down the deepest spill point. In this
88:12 , the 550 value default dependent column would go from that same contour if
88:19 hits the fault. But now it goes down to the oil water contact
88:24 the gas water contact. So it be less than the total fault dependent
88:42 . So the default dependent closure equals difference between the highest contour that intersects
88:48 fault and the deepest still point. fault of Bennett column height equals the
88:54 difference between the highest contour that intersects fault and the gas water or oil
89:00 contact. If the structure is not to spill, these two will be
89:06 . Okay, and then static falsetto is defined as the fault trapping capacity
89:12 the geologic time scale. And this what kind recovered column whites and
89:18 Republican hold. What are the potential dependent Colin White's and it's a function
89:24 the fault rock, temporary enter dynamic faults. Your capacity is the
89:30 potential of faults on the production time . What cross fault flow will occur
89:35 production? This is what kind of yield speed determines what cross fault flow
89:41 occur during production and it's a function the full rock permeability. High dynamic
89:47 differences across the fault in those days crucial, differences are much greater than
89:54 static. What's your dependent pressure Capillary is what makes false. He'll
90:04 like top seals, folks do have and permeability. They're not glass.
90:10 here we have thin sections of of fault with the under formed rock
90:15 the faulted rock here and so the of the green socks and reduction of
90:19 ferocity reduction permeability. But there is finite porosity and permeability than that fall
90:29 . So what makes this fault zone is cap hilarity. What is the
90:34 that it takes for hydrocarbons to invade space? And that's shown here in
90:40 diagram to sand grains here and Water wet poor throat here credit cards
90:47 in the red and the capital of pressure. Is the displacement pressure required
90:55 those hydrocarbons to displace the water in poor throat between the bounding sand grains
91:03 that's a function of the the radius curvature of the poor throat, the
91:10 of the wedding angle for water, is always one. And this gamma
91:15 inter facial tension of the fluid. so the same rock gas and oil
91:22 different inter facial tensions, different And so the same rock we have
91:27 ceiling capacities for oil and gas. that's uh that's shown here by the
91:34 of inter facial tension as a function depth. And what that shows is
91:39 oil and gas have different inter facial under all the same conditions. So
91:46 the same rock will have a different capacities for oil and for gas.
91:57 , so this is a cross plot fall rock permeability versus host rock
92:02 Each point on here represents two measurements a corpse look like this. one
92:08 the uninformed broad and one of the at the end of the court.
92:14 . And what this shows is that rocks have words of magnitude less permeability
92:19 their original host truck. It can as low as 10 to minus five
92:25 the original host rock permeability in the symbols here represent Shelley thought rocks what
92:33 call phyllo silicate framework, fault rocks these have lower permeability, ease and
92:39 kind of place. I'd stuff high to gross, low local a bearing
92:46 . So everything being equal of philosophical rock will have lower permeability then a
92:54 of clean shirts going into grocery rock no play. The other thing that
93:00 shows is that even when we have CNN fault contacts in high mental gross
93:07 growth rocks and catapults sites here represented the yellow clouds, there will still
93:12 a reduction in permeability that gives these and thought contacts profile, static and
93:19 folks, healing potential and then we about just the visual analysis where we
93:30 a cross section, that's a view at the fault. So an object
93:36 section of this fault for example, have the up Thrones hand here of
93:41 had a here the up Thrones can here, your throne seems being in
93:46 football and they're just opposed with a thrown stands here and here. So
93:53 checks position sections are kind of fault scandal is showing both the up and
93:58 thrown sides of the fall. And also referred to as Alan sections or
94:02 one sections, right. We have independent types of shell garage equations.
94:15 is the show God ratio, what the place of your potential? Show
94:20 ratio is defined as the total feet shale, define it by the throat
94:26 each point on the fall, when throat gets large, relative to the
94:31 to gross in the section, when gets large relative to the individual sansho
94:36 in this section, we'll go threshold equals one minus synthetic growth. So
94:42 can use this to get a quick of what the shale graduation would be
94:46 any fault place your potential represents a different phenomenon. It represents the length
94:54 the continuous shale or clay smear that out into the fault zone. And
95:00 idea of this is that in an of setting the vertical load on a
95:05 bed will be greater than the normal across the fall and so on,
95:12 will be squeezed into the fault zone stepping on a toothpaste tube and the
95:16 severe potential measures the length of each those continuous shale smears gets squeezed into
95:25 false stone. Now we adapt the grounds ratio equation to account for different
95:37 contents and the different rocks. So show got ratio but in fact equals
95:44 The 5% claim. Each layer divided On the 5% claims later times the
95:51 of each layer divided by the throw then multiplied by 100% to get a
95:58 and it it equals the percent clay the displaced interval. So here's an
96:09 of a juxtaposition section, looking at fault and with both sides of the
96:15 . The the ark throne layer is in the light brown color here.
96:21 mean down throwing light shone a light color here. The up thrown layer
96:25 shown by the yellow in here. so whenever we see a white space
96:31 here is where we have a sentence contact on the fault. The blue
96:36 represent the shell God ratio contours on fall and these will vary both up
96:42 down the fault and along the fault a function of variations in a strategic
96:47 and variations in her throat. So gets us to the false seal calibration
96:59 and these come from studies where people looked at the Sheldon ratio across the
97:09 and compare it to the pressure differences the fault is ceiling. So we're
97:14 at known ceiling falls where we have and we have sandals show contacts like
97:21 here by the red, where we so wet sand on the front side
97:26 the fault in hydrocarbon bearing, stand the back side of the fault.
97:32 so we can look at the G. R. Values along these
97:35 and compare them to the pressure differences these points of the fall. So
97:41 go up and down the fall, at the show graduation on the fall
97:47 comparing those shell guards ratio and CSP to the pressure differences across the
97:52 Shown here by pressure depth diagram. globally from all these empirical field studies
98:07 see, we see abundant examples of falls. They include CNN sand,
98:13 falls, ceiling thrust ceiling, active ceiling thrust and sealing active normal
98:21 Mhm. We see false ceiling, plastics and carbonates. And those examples
98:29 from studies and all these basements shown the stars. So these occur,
98:34 not unique to anyone based and they globally. So that gets us to
98:43 shale gouge ratio cross plots where we shale gouge ratio across the bottom versus
98:51 difference across the fall as the Y and these different colored clouds representing ceiling
98:58 at different burial debts. So if know the shell God ratio and the
99:04 depth, we can estimate the ceiling of the fall. So for example
99:10 a for fault In a shallow depth than three km With the shell gas
99:16 of 30%,, We can go to 30% value here. The strap,
99:21 up to where it hits the blue here and then read across What the
99:27 pressure difference is. That that show ratio of 30% can hold in this
99:33 about 3.1 bar of 45 P. . Sorry longer on this side.
99:39 on this side. The other thing shows is that when we extract with
99:43 different envelopes To the zero Shell God . Access here, These faults still
99:50 some ceiling capacity even though the show ratio is zero and that comes from
99:56 reduction in porosity and permeability that we with the cattle, plastic rocks.
100:05 that that reduction frosting for mobility gives some small ceiling capacity even if there's
100:10 clay in the rock. Show dogs and places where potential are not
100:19 So here's a plot of place here versus pressure difference across the fall.
100:27 we're looking at exactly the same diagram we saw with the show God
100:33 but now we're plotting play spirit potential and we see a slight increase for
100:39 a spare potential values. But then higher clay scare potential values, there's
100:46 there's no consistent, there's no consistent , there's no consistent relationship between the
100:51 capacity and placed their potential. A simplification for sdrs to get it
101:04 a triangle diagram In this show show ratio as a function of one gamma
101:11 or one V shale log and the values. So here's the triangle
101:17 here's my official log in this, the color code A. Here the
101:24 contours shows the str values for the thrown side of the fault with increasing
101:31 of throat. So for example at top of san a where problem Throw
101:41 is 25 ft. We have the guard ratio in the yellow here of
101:49 mhm. Well between yellow and so about 20-30%. You're on the
101:55 contours with increasing throw. If I the throw to 100 ft, that
102:03 point on the thought will have a gouge ratio In this light blue color
102:09 representing a shell graduates from about And then as we go out to
102:16 and larger throws, these shell God become relatively constant. So for
102:22 at the top of the sand. For any throw greater than about 125
102:29 . Michelle Godrich was going to be . 50-60 sure. So here's how
102:41 um oh these triangle diagrams work. example. So here's my official
102:51 my triangle diagram, here's the uptown of the fault, here's the down
102:57 inside of the fall and so CN would be follow a trajectory like
103:05 Sand too. Would the shell graduations SAN too would project across like
103:14 Mhm. For this range of throw between 150 and About 350 ft
103:22 Juxtaposed to sand one with SAN And I'm going to have a show
103:27 ratio of The blue color here 50 60%. And we don't normally add
103:39 down front side of the fault but helps clarify how these china diagrams can
103:48 dynamic false heels right now, what we see is that pressure induced
103:57 . Production in these pressure differences across greatly exceed what we see on the
104:02 steel capacity. So this dynamic falsetto refers to the baffling potential faults on
104:09 production time scale and specifically what cross flow will occur during production. It's
104:16 for identifying undrained fault blocks or mm conversation in fault blocks and producing field
104:24 development opportunities and it's a function of fault rock permeability. So here on
104:29 bottom I have across part of pressure versus shell God ratio while the static
104:36 have pressure differences going down here in cloud of data on the production of
104:42 pressure differences fall in these red hazard which greatly show that they greatly exceed
104:49 we see on the static fault skill the static timescale. All right.
104:57 this is our effect of the permeability the false. So I have a
105:04 here with a fault. The fault zone here, The depleted reservoir on
105:09 side, an un depleted restaurant on reservoir on this side. When I
105:15 this side, I increase the pressure across the fault. That's my production
105:19 these pressure difference with continued production that P exceeds the capital's central pressure of
105:26 fault and I start to bleed hydrocarbons the fall. I'm gonna break the
105:31 parental pressure, but the hydrocarbons bleed the fault at a very slow rate
105:37 to the low permeability. Um and in these large pressure differences even though
105:44 broken down the capital oriental pressure on phone. Okay, so one way
105:54 estimate the permeability is using these cross of post rock permeability versus fault rock
106:02 . If I know for example, I mean, Mhm. A false
106:08 of cataclysm sites with virtually no shale Iraq. Very high net growth reservoir
106:15 a host permeability of 1000 million I can read up along here and
106:20 an estimate that My fault rock permeability be somewhere in the middle of this
106:27 . It will be a reduction of 10 of the minus two. So
106:31 fault rock will have a permeability at 10 km. Mhm. For oil
106:38 that will be a strong baffle for reservoirs, that will not be a
106:42 at all. Thank you. So let me go back if I have
106:56 shay lee reservoir of loan into gross , my data will lie in this
107:03 framework fault rock represented by the great here and everything else being equal.
107:09 fault rock will have a much lower if I come along with it from
107:14 millas Darcy's and go up in the of this great cloud. My fault
107:19 permeability will be 1-2 orders of magnitude than in the high net to gross
107:34 . Alright, reservoir simulation models deal fault transmissibility multipliers rather than actual fault
107:44 and the fault transmissibility multiplier is defined the ratio of the flow with the
107:50 to the floor without the fall. so the values for this range between
107:57 for a completely no flow case to for a case of unimpeded flow and
108:04 detail these are determined by this equation the length, the dimensions of the
108:12 . Salt block, the spacing of grid. Salt block the well the
108:18 of the faults are and the permeability the fault zone. All these things
108:23 convulsed in this equation to give you ratio called the thought transmissibility multiplayer.
108:29 this is going to vary along your as a function of Mhm The Gods
108:35 and permeability and fault throw. so we can estimate the fault zone
108:45 as a function of throw from this spot here. We've got fault displacement
108:51 fault thickness here and a good average this is that the fault thickness Is
108:57 1/100 the throw. So if I I have a displacement of about 100
109:03 . the fault zone thickness will be will be about a medium.
109:17 mm hmm. For reservoir rocks with hi str harvey shale values. These
109:25 are used to estimate fault rock This is a plot of shell God
109:31 versus fault rock permeability. And these all different functions by for different burial
109:38 for different displacements and by different authors see for shell God ratio is greater
109:44 About .1.15. They define a fairly trend but for low shell Godfrey shows
109:52 a lot of divergence and for these graduation of fault rocks, you should
109:58 the cross plots of for rock perm host rock. Current estimates for rock
110:07 . Okay, right, so for reservoir rocks with Very low claiming that
110:15 shale lesson about .1 you can take average through this cloud to estimate what
110:20 full rock permeability is going to So for false feels static fault seal
110:33 to the fall trapped in capacity and time scales. It's controlled by the
110:38 rock templar entry pressure and it determines colum fights for concealed reservoir reservoir sand
110:48 sand felt, contacts concealed, active critically stress fault seal, thrust faults
110:55 and that false real capacity is a of the shell guard ratio and it's
111:01 a function of the class in your . So we can use those cross
111:05 of S. G. R versus difference across the fault to estimate falsetto
111:10 is a function of msgr dynamic Field capacity refers to the bathroom potential
111:17 on the production time scale. This important for identifying andre and fault clocks
111:23 producing fields. The dynamic pressure The production in these pressure differences are
111:29 greater than the static pressure differences. these dynamic pressure differences are controlled by
111:36 fault. Rock permeability And full rock are typically 1-5 orders of magnitude less
111:43 the original Underperformed reservoir permeability but not dynamic false heels and response simulators.
111:51 simulators are expressed as fall transmissibility multipliers FTm right. And these represent the
111:59 of flow with the fall to flow the fall. And so they ranged
112:05 zero for the no flow case to for the unimpeded flow case in these
112:10 function of default throw the God from guys on thickness and the reservoir model
112:17 size but it's done. Salt and tectonics. So the primary factors influencing
112:31 movement. Our buoyancy, differential loading extension in a taco. In assault
112:39 , we get this evolution of structures rollers. Two pillows to die appears
112:46 increasing vertical relief in this direction and appears can be separated into active time
112:56 where the salt I appear actually pierces through the sentiments and passive di appears
113:03 the dye appear. It stays in fixed elevation and sediment accumulate around it
113:09 the basement. Subsides around it, dye appears are those that form in
113:16 to the salt flowing into Phil fill area of extension and basement faults can
113:24 a big influence on salt structures and die appears a lot of his
113:30 Salt sheets are those where the salt climbed up to some the strata graphic
113:36 above its original deposition level and extended , and these give rise to flanking
113:45 flaps and overturned limbs, projections of assault parties. They also give rise
113:51 these many basins formed by a local centers on top of the salt.
114:10 , okay, so the physical properties salt. Salt is Senser than sediments
114:16 shallow depths of less than one km . It's greater than one km.
114:21 salt is less dense than the sediments this gives rise to the buoyancy of
114:27 salt. So these are the factors salt movement, density, inversion of
114:34 . The differential loading extension, contraction gravity spreading rollers pillows die appears are
114:46 autochthonous salt structures are. This difference rollers pills and die appears represents increasing
114:56 where we have complete evacuation of the . We get wells where the Mhm
115:02 overlying the salt touchdown onto the And these also give rise to turtle
115:11 where an initial similarly accumulation is completely in the fins now lie down on
115:20 of the basement and then we get active and passive di appears active with
115:30 pierces up through the sediments impassive die where the salt stays in place and
115:35 sediments subside around it and mega flaps an artifact or result of this town
115:43 . And along these mega flowers, can also get salt overturned limbs where
115:51 salt has acted like a tractor tread a caterpillar tread or a tank treads
115:58 invert. The originally overlying sediments reactive appears are those who are the salt
116:08 gaps formed by extension. Mhm locked assault structures and sheets are formed by
116:16 movement of assault up to a shallow Extrusion at that shallow level in coalescence
116:21 the dye appears into one 01, continuous treat shale tectonics here we're talking
116:31 mud die appears size and wipe out . They superficially resemble soft I
116:38 but there are always symmetric where the structures are not often psychometric, often
116:45 . They are distinguished primarily by the absence of salt geometrically. They can
116:51 tothe rust in the deep part, on But they are usually distinguished by
116:59 from toe thrust by good quality three data. So here's a here's a
117:09 section showing the different types of salt . Salt here. Mini basin here
117:17 continue to position this mini basin. will drive the salt into the diabetic
117:23 . This will continue to subside and to accumulate more sentiments of forming on
117:29 basin, a withdrawal base in a or a rims incline is assault means
117:36 relative to these patients. This is we get the salt walls to die
117:40 in the pillows. So the salt vary with depth over burger in salt
117:50 and you see this both in the of Mexico and the North sea where
117:56 , thin shallowly buried salt, we these salt rollers low relief. They
118:02 into um walls and pillows with increasing of salt and increasing burial and increasing
118:10 leaf and ultimately they can become die or actual salt walls with increasing burial
118:19 increasing amounts of salt. Alright, is an example of how a turtle
118:31 . So I have initially I have fix here with the deposition of sediments
118:37 top of that salt that loads assault of the salt to evacuate and the
118:45 sediments thin onto the flanks of the with continued deposition and that salt evacuates
118:53 . It forms what's called the weld the sediments ground out onto the basement
119:00 , what was what were thins on flank are now lows here and and
119:08 here and so we end up with thing called the turtle structure, whether
119:16 thickest in the center here and then down dip on the flanks here.
119:29 here is some seismic examples of turtle . You can see the salt
119:36 The turtle structure here, thick in middle then where it downloads onto the
119:42 , nearly complete welding of the sediments top of the salt here. So
119:48 is pushing down on the basement rocks with complete evacuation of assault.
119:53 and then these overlying sediments draped over paternal structure. Okay, this shows
120:06 of the evolution of reactive dye So here I have an extension of
120:11 with normal faults here, grabbing here extension, I'll get more and more
120:19 faults. Accommodating the extension of the section and salt will flow into that
120:25 formed by the formed by the increasing of extension. And this gives us
120:31 called a reactive dye appear where the is reacting to that extension. Active
120:41 appears in contrast like this one where salt punches its way up through the
120:47 from creating these steep, leading inclined adjacent to the salt and the gulf
120:57 Mexico is Divided into these four different . The onshore and shelf where we
121:03 talked in assault and here we have , pillows, domes and die appears
121:09 the shelf. We have both on finish and launch an assault, giving
121:16 to die appears in many basins. we get further offshore out of the
121:21 , we have a lot of salt many basins out here and then finally
121:28 get down to the toast. Pretty . These are locked on assault canopies
121:32 maps. Mhm. So here's a showing that progression of structures. So
121:41 a cross section C level their coastline , montagne from his mother luann salt
121:47 here, unsure. We have these structures that route in the mother luann
121:55 here, the rollers and pillows die and many victims were there additional sedimentation
122:02 on top of these documents structures going outboard, assault migrates up section and
122:11 into these elephants canopies that then formed locust for many basins where sediments are
122:19 on top of that salt causing further . That further evacuation moves the salt
122:25 down debt. Where you get these , canopies, Naps and canopies at
122:30 six B of Scotland. These are of the different types of structures onshore
122:41 shelf. We get these rollers and in die appears on the shelf where
122:47 have autopsy autopsy and assault. We these salt and apps that form the
122:54 for many basins where the sediments deposit causing further evacuation on assault and when
123:02 get to the slope an abyssal We get these salt naps shown here
123:10 locally overturned sediments at the base of maps. So here's an example of
123:24 of those locked and assault canopies. see the salt here, it's completely
123:31 and is separated from the mother salt up section here to where it eventually
123:37 emerge on the sea floor. so this is a typical salt pillow
123:46 roller structure assault body here, sediments we did this as an exercise where
123:52 faults come down and soul into the . And you get one major normal
124:00 with conjugate anesthetics, synthetics, girls extending the section up here in the
124:10 load the salt load the salt causing evacuation and causing rotation of the deposited
124:18 in this orientation so they sub parallel in the deeper section. So,
124:29 a cartoon showing the evolution of a appear in crimson klein salt here deposited
124:36 here epicenters here and here. The of loading moves the salt from flying's
124:44 into this stratospheric structure and with continued , these things are subside eventually to
124:55 onto the basement here, causing rims adjacent to the salt structure. As
125:07 example of assignments section across the salt appear, you see we've got a
125:14 normal structure with concentric structure contours contouring the salt diet. So pushing up
125:21 here, and one of the problems this is that the diet their flanks
125:26 very poorly imaged. So when we close to the salt flanks, we
125:32 really know where these sediments and and the salt starts. Here's an example
125:42 how these salt structures evolved with So from here to hear, um
125:50 progressively more sediments on top of the . As I do that the salt
125:55 this portion of the section evacuate and was up to this low pressure section
126:03 , we've continued sedimentation here. Eventually sediments can touch down welding completely evacuated
126:11 from here, the salt moves up show a little and extruded onto the
126:18 floor and that continued sedimentation rotation gives to the steeply dipping beds adjacent of
126:25 fault and even overturned beds immediately adjacent settled here. So here's here's an
126:38 that here's an example of what's called mega flat from the gulf of Mexico
126:42 a half assault body here that's been by the loading of these adjacent many
126:50 , forcing assault to move up here a canopy where the salt now coalesces
126:57 multiple multiple ones in these die appears the Soul becomes one continuous canopy across
127:03 top here, these sediments within the basins are important exploration targets now they
127:12 freeway closures against assault here, but very high common rights in there and
127:20 shows how they evolve. So, starting with salt here showing the black
127:25 center here and here on the two of the mason salt di appear with
127:32 deposition assault evacuates flows into the dye as it does. These sentiments that
127:40 on top and adjacent to the dye are rotated to higher and higher angles
127:47 eventually the salt body. Mhm emerges adjacent salt bodies to become one continuous
127:54 with these completely, with these mini completely enclosed within the salt, with
128:00 steeply dipping limbs adjacent to the salt . Sure, okay, so the
128:11 seal capacity. The salt traveling capacity equal to the sequel to the fracture
128:19 . And so sealing capacity of the in situations like this is determined by
128:26 minimum horizontal stress across the minimum zone in this location. And this comes
128:34 studies in our mind, here's a depth plot from Vermont with the cough
128:40 and fluid pressures from fluid inclusions shown and what these show that the food
128:50 in the reservoirs in salt contained pressures to the maximum mention the minimum horizontal
128:59 . The leak off test trend here that's showing us that the ceiling paseo
129:05 is equal to this fracture gradient Now, going out onto the shelf
129:17 slope, we get these many basins evolved by deposition of loading and salt
129:24 . So, we start with a body like this. So it's deposit
129:31 on top of it that causes the to evacuate and formal law that then
129:37 the the location for continued sedimentation and building. So this sedimentary accumulation
129:46 causing the sediment assault to evacuate further further until eventually the sediments caused assault
129:54 completely evacuate. You have salt wells the base with adjacent salt ties here
130:01 here, sediments on that being those ties right now in the gulf of
130:13 . All this, This update loading what drives the allotment assault base inward
130:18 form these gelatinous salt sheets. Salt at the muslim. And here's an
130:31 example of one of those sheets where the salt body here, it's climbed
130:36 section here, mm hmm. In overline section it's now extended by depot
130:43 by deposition on top of salt body continues to drive assault evacuation basin work
130:51 the base of the salt. We these overturned limbs. Here's an example
131:03 one of the salt naps with the limbs here and we think he's involved
131:08 this tank tread or conveyor belt mechanism sediments are initially deposited on top of
131:14 salt and with with salt movement in rotational movement of assault, These sediments
131:25 were deposited on top of the salt are rotated below the salt to become
131:31 salt overturned beds. Like we see and shale tectonics. These are modern
131:43 dieters. These are examples from the Mountains, but these require are highly
131:49 pressured sales what they generate our size wipe out zones like like this.
131:56 can be distinguished from south by appears by the known absence of salt.
132:02 like Nigerian Borneo where we know we no salt deposited. Some of these
132:07 of diabetic structures will be mud die . They're very they're generally very symmetric
132:15 distinguishes them from what we see offshore the toe thrust and they have this
132:19 of christmas tree type structure where initially get a month I appear it excuse
132:27 the near surface with continued burial, pressurized that monday I appear more and
132:34 get another exclusive event. So you this series of toadstools or christmas tree
132:40 structures moving up from the deeply over mother shell here to show our levels
132:47 the basement. No, so distinguishing versus shale deformation. The some mobility
133:01 our property related to the high viscous and initiates at over burdens of a
133:08 1000 ft. The salt is primarily within constant density and viscosity of about
133:15 10 of 17-10, 10 of 19 . Some mobility is limited by evacuations
133:24 wells or touchdowns in the sink lines rafts fall related from his common diapers
133:31 common a lot from his sheets evolving large canopies and that's are covered in
133:40 . Tectonics are usually confined to one unit insult moves at slower rates over
133:47 distances compared to blood die appears and tectonics, Shale and contrast is most
133:54 when overpressure, it tips grip depths than 10,000 ft. Mhm, it's
134:00 variable in composition and flow is related the over pressuring effects rather than the
134:05 of the shale. Alright. It's by de watering. So when you
134:12 the water the shells there are no mobile to shale is only mobile to
134:16 . These die appears when it's highly pressured and this episodic flow results from
134:24 de watering on vs. Very Internal processes in the salt. Thought
134:34 flow is common but only with overburden 10,000 ft die appears are common but
134:40 evacuation is uncommon because of the mass the water shells. That minor shell
134:47 are common. Those kinds of christmas limbs that we just saw and it
134:53 affect multiple horizons as they are buried appropriate greater and greater debts.
135:04 full trust us and we talked about , fault penfolds, fault propagation,
135:10 the text unfolds, duplexes and hydrocarbon . Good to see you. How
135:25 you? How are you doing? want to take a break or do
135:27 want to go ahead for this next ? Can we continue to the next
135:39 ? Okay, is that all right Angela and Meg? Okay, we'll
135:45 on. Right. Alright, so have two kinds of compression structures.
135:53 thin skinned fallen structures in the thick , foreland basement court uplifts represented mainly
136:00 the U. S. Rockies. full thrust belts are thin skinned,
136:05 angle attachments and near the top They occur in convergent and passive margin
136:12 and have the same geometries in I follow critical taper theory. The
136:18 have to balance this is essential. the four essential building blocks for balancing
136:24 are these fault bend folds For ford's detective folds in duplexes. As
136:31 as you confine your interpretation to these types of structures, it will be
136:37 double false project into the sink lines these structures. The seismic imaging is
136:44 poor right cross sections must be balanced restore a ble to do that.
136:51 hanging wall in football could always have match and the hanging wall flats.
136:55 have to equal the football flats. trust funds, concealed strike closure and
137:02 features are critically important to determining Following the fire departments in the trap
137:09 football traps are indicated by those saddle inclines and talked about. Um So
137:18 faults, mm hmm, maximum stress horizontal, so it's signaled.
137:24 Max signage, um swim, Krogh is the minimum stress and sigma
137:35 is is perpendicular to this is parallel the striker falls. And the defamation
137:51 the thrust belt is determined by this taper theory. That's the first order
137:57 and that's a function of the basal . The Tacoma. Just put it
138:04 and the strength of the rock within reg within the wedge where you have
138:11 based compression structures. You have low week. Tacoma, high fluid pressure
138:18 and thrust with multiple virgins is detachment , falls and thruster discontinue so long
138:25 and you get more symmetric type structures you have a stronger shale based
138:33 The folds and thrust consistently verged towards forming back thrusts are rare and the
138:39 and thrusts are relatively continuous so long . So the Canadian rockies are an
138:49 of the high critical taper wedge. these non travel thrust sheets mm
138:56 They consistently verged towards the basin of fallen, their continuous along strike,
139:01 this is representative of the Canadian rockies over thrust so mandy and in parts
139:07 Taiwan. Conversely where we have a salt based attachment we get a low
139:17 taper get these kinds of fold and with multiple virgins is with symmetric structures
139:23 appearing black structures of detachment falls. these structures are characteristic of the people
139:31 Nigeria mexican ridges convince state, bay and in Pakistan. Come on,
139:46 . Um because our subject, it so poor, it's critical that we
139:53 balanced cross sections and any any permissible . Any permissible interpretation of a cross
140:03 like this must balance. And that rise to these kinds of geometries.
140:14 on one balance section represents only one many possible solutions. So even though
140:20 section is balanced, there may be viable alternative interpretations in this example shows
140:28 different duplex interpretations of the same structure , all of these are balanced herbal
140:35 they represent very different subsurface structures. , okay, we did some exercises
140:45 this. That balance double sections must matching ramps and flats. So in
140:51 section like this, it's easier, easier to define the foot wall flats
140:57 ramps where you have a flat rampart comes up section flat here,
141:02 second ramp where it cuts up section the flat here in the hanging
141:09 you have to have the same corresponding and ramps and those will be defined
141:15 the strategic where the thought could subsection around here and here and where the
141:22 has been in parallel and then hang here here. So an example like
141:28 , we have 1 2 ramps in Corresponding to two ramps, two ramps
141:35 the hanging wall corresponding to two ramps the foot wall and two flats in
141:40 foot long corresponding to two flats in hanging wall. So with these matching
141:47 and flats, this section will be . So, requirements for a balanced
141:57 . The bed lengths must be the for all the deformed beds. The
142:00 lengths and thick, as soon as constant in the deformed and under formed
142:06 for those beds of shale or overpressure that do not do not maintain constant
142:12 and thickness. The cross sectional area constant thrust, have a rep flat
142:21 , the thrust ramps cut up section the transport direction deformed beds must be
142:26 . Hubble to an original sub horizontal . The football ranch and flats must
142:33 the hanging wall ranch and flags. structural styles we draw in cross section
142:40 equal those that we see in map maker. Outcrops and pin lines and
142:45 lines at the front in the back their store session remain vertical in both
142:51 deformed and the un deformed state. here's an example of those loose lines
142:58 the pin line here in the front this loose line here in the
143:03 When we restore this. When we form this, wow ! The loose
143:09 remains vertical in the under formed So these are the four types of
143:23 that are inherently balanced duplexes, fault folds, fault. Ben folds and
143:29 bottom triangles of us. Here in structures, the deadlines are constant to
143:34 thicknesses, front, constant. The all ramps and flats match the hang
143:38 ramps and flats, but slip along fault is not constant. So here's
143:49 this animation representing an example of a tenfold. And we see that as
144:06 evolves. There's no vertical displacement of hanging wall beds here or here at
144:12 front of the thrust sheet. The back wing dip of the fault's
144:17 fooled here equals the tip of the . The sink Lionel fold hinge here
144:25 fixed to the base of the The fold hinge here in the hanging
144:31 is fixed to the top of the ramp. This full hinge in the
144:40 wall occurs at the top of the ramp here and we'll move with continued
144:48 . Whereas these and these will stay with continuous desperation. So general characteristics
144:59 a fault. Ben phone or rampant . Can you all hear four more
145:05 ? Flat ramp, flat geometry, , graphic levels here, unchanged from
145:13 they are in the uninformed state. vertical displacement of the hanging wall beds
145:19 . Tom this sen coin will actual remains fixed to this, a point
145:26 the fault cuts up section. This surface remains fixed to where this football
145:33 goes onto a betting playing flat The back winded here equals the tip
145:40 Iran. The displacement is relatively constant the hanging over here. And these
145:48 surfaces are tied to the football cutoffs and here and they're going to move
145:54 displacement of increasing the width of the a clinic crest here and it's only
146:01 in the structure. Then we get of the beds and older beds thrust
146:06 younger beds in front of that. behind that, we just have a
146:10 photographic sequence. Um so here's an of fault propagation fold with continued
146:23 And the important thing to add on one very noted most of the
146:28 but the important thing to add is the the kinks here are not
146:32 And so this overturned limb. Um not faulted through. It's not faltered
146:39 the crest or the basement default default into the base of the sin
146:45 but the at the leading edge of fold of the better overturned and not
146:50 fault. A variation on that is your fault propagation folding shown here where
147:04 follow other geometries of the fault informed now in the leading edge of the
147:10 . Here the beds are deformed by structure deformation leading to steeper, overturned
147:16 thin beds in the foreman. Here attack unfolds. Detachment folds are attached
147:27 , liftoff Arbuckle folds of overlying inducted salt or or overpressure shales. Here
147:34 see some examples of that in our in the Euro mountains. And incompetent
147:39 be here with this nice symmetric Go to church folds are can be
147:45 or asymmetric or have overturned. Full limbs. They have variable versions diverge
147:52 the foreland and towards the hinterland. individual forced full skinflint, virgin so
147:57 strike the fold limbs are independent of false vetting false if they develop our
148:06 and propagate from the limbs to the detachment levels that propagate from the middle
148:13 the fold limbs, the highest train of the limbs down to the catholic
148:17 and upwards higher end section. These globally wherever we have solved deductible shales
148:23 provide a Tacoma earlier drum and we determine its tablet level from those depths
148:30 detachment calculations like we did when we the area of the deformed bed and
148:37 it to the height above the We also get these detached structures as
148:42 of synch line faults and folds of a response to the space problem and
148:47 those structures. And they're very common all these different provinces. So again
148:59 reflect that the critical taper is the order control here with salt based structures
149:07 a low critical taper of the salt a week to coma. And that
149:12 us these attachments structures, phones and with multiple virgins is that are symmetric
149:19 discontinuous along strike. Mhm. So are characteristics of detachment folds and comparison
149:36 for bill force I thought propagation falls detective control where the fault Ben folds
149:45 the detector and the propagation folds here related to the geometry of the underlying
149:52 . The detachment folds are independent of of any underlying faulty on the tree
149:58 faulting. If it occurs, it's secondary to folding. We get faulted
150:08 folds where the strain in one of limbs become so great that falls begin
150:13 propagate both upward and downward to the level. And so now we'll see
150:22 developed that very similar to what we in fault propagation folds. But the
150:29 occurs first and the geometric relationships of hangar or bench and the faults don't
150:35 what we see in the fault propagation . Mhm. And then we talked
150:44 depth detachment exercises where we can measure length of the platform bed compared to
150:52 length in the present day state, the area. Not that bad.
150:58 compare those lengthen areas to the displacement the height of both the detachment to
151:06 that. Um I can't guarantee elevation the detachment level. And this this
151:18 the exercise that we did. And got this grass where you planted.
151:29 And so Syria versus the height above reference level. A line projected through
151:36 points gives you the slope of the gives you the displacement to devalue
151:45 And the intersect of that line with X axis gives you the height above
151:52 Oh what about the detachment? Because have the difference between the reference level
151:56 the detachment. In this case we a simple exercise where the reference level
152:03 an attachment. Mm hmm. In cases where these are not the
152:10 This line will shift over to the and hit the X axis somewhere.
152:17 to the left of the origin That gives you an aged value that
152:22 can use to extract weight from the level down to the task.
152:32 this concept of regional level is valuable correlating across before structure like this.
152:39 in the fault propagation of false landfalls attachment folds. This strata graphic level
152:45 the trailing edge is the same as original regional level and is the same
152:51 what we see in front of the . And so we can project that
152:55 level from any place that is well across the field. Out to the
153:01 section here to help me correlate the were made from this part of the
153:07 to this part of the section. this example you see the regional levels
153:13 the slight blue are not the And that's telling us that our takes
153:19 this side of the fault are not to the picks on this side of
153:22 fault. And we need to pull up so that the blue level here
153:28 to the level here in the deepest here in this orange horizon will then
153:34 the same as what we see over . Right. And we don't need
153:39 . Best to draw these. We connect these by connecting some coins and
153:49 hmm. Okay. In detachment folds faults, propagation folds from these steep
153:57 like this are going to give us , this white belt. Someone's sizing
154:02 data and we need to overcome these running git meters in the log and
154:10 balance double sections. Duplexes. So are sequences of fog. Ben folds
154:21 you have. Okay, an initial been filled with a small displacement and
154:26 the football collapses along successive series of giving you sequences of false landfalls piling
154:35 into these accumulations called duplex structures. we have mm hmm, a full
154:50 duplexes and passive roof duplexes. The is here everything is virgin towards the
154:57 . And all this displacement is taken by translation of the hanging wall sheet
155:01 the foreland, peter with a passive complex. All these wages uplift the
155:09 sentiments here, but the displacement dies here and the displacement along these wedges
155:16 taken up by back thrusting, betting detachment here. So this is the
155:23 between a normal duplex and a passive duplex. And when we get these
155:30 , either this type for this we'll get these saddle shapes inclines in
155:37 overlying beds that tell us we've gotta closure at depth in one of these
155:43 type structures. Alright, the Waterton field is an example of one of
155:54 duplex structures, the reservoir, the reservoir horizons and the Mississippi. And
155:59 here in the orange. And you all these duplex slices piling up to
156:05 an informed structure here, here's an of a passive roof duplex from Canada
156:16 seismic section here, sink line out . Main thrust coming out here a
156:23 of intricate slices from here to form duplex. But now these wedges are
156:30 for by back thrusting of a bedding roof thrust here. So this displacement
156:36 not go out into the four It's compensated by wedging along this roof
156:45 . Mm hmm. So we went a lot of structures looking at the
156:53 accumulations compared to the disclosure and cusiana an example of one of those that's
156:59 filled with respect to the dip And we have we have active thrusts
157:06 that are still ceiling trafficking accumulation at mirador level here. Wow. And
157:12 very large colonizing pressures even though the is seismically active today. So,
157:24 , we have to consider the hydrocarbon in the february for each one of
157:30 structures. And this is an example deepwater Nigeria. You can see the
157:35 coming here. It happens to be attachment for this steam on this land
157:42 the south end, steep on this , the northern end and symmetric in
157:48 the structure is under filled with regard the total closure. And that's because
157:55 february for hydrocarbons is limited by this polygon outdoor. The detachment folds here
158:02 here. You know, these long , flat simple lines, so he
158:08 that comes up here or here is to migrate off to the northeast here
158:16 off to the southwest here and not into the core of the structure
158:22 The core of the structure here will get high departments from this black dash
158:27 political area. And so it's a limited fetch area compared to the size
158:33 the structure. and so we went 17 fields. We've known field limits
158:44 Five of those 7, 7 were limited by default sealed. Only one
158:49 limited by the strike closure. Only was limited by the potential top steel
158:55 And 10 of the 17 are limited hydrocarbon charge. So looking at that
159:01 area like this is very important for whether you can what what final fighter
159:11 you can put in the truck. hydrocarbon accumulations occur in all types of
159:20 throughout thrust belt structures. The thought folds, paul congregation falls, detachment
159:26 duplexes And of the 17 fields with fields limits More than half 10 out
159:32 17 appear to be limited by hydrocarbon . And that limited chart is caused
159:39 the tights inclines the adjacent of the that limit the french area of the
159:50 . Right, alright. So then talked about Rocky mountain style basement cord
159:55 lists these types of structures and these the other end member of the compression
160:05 where the full thrust belts represent these guys when basement involved. And now
160:12 have major shortening of the basement and basement corridor Poulos. The characteristics of
160:23 basement court up lists, they've urged multiple directions. The virgins is variable
160:29 respect to plate convergent vectors. The hang while basement box are essentially under
160:38 . Oh, the basement is under overturned beds are common in the reverse
160:44 footballs. These flaps of sediments that see in the footballs, the elevation
160:50 dip of the top of the basement the hanging wall is a function of
160:54 geometry of the underlying master fall. , the seismic imaging is necessarily poor
161:01 of the steep dips and the velocity . The Master fault is commonly a
161:07 slip, blistered fall with little or strike slip in this and get these
161:14 flaps of Centenary coral rocks. Comment the football of the Master thought in
161:21 interest of thrust or great fold So we talked about for these basement
161:25 uplifts are really artifacts of the limitation scientific data and are impossible balance and
161:33 geologically impossible. So the structural characteristics shown by by this example. This
161:43 the the golden thrust just west of colorado. The ranges are bounded by
161:50 faults or sharp fletcher's related to underlying falls. This basement faults and took
161:56 30 to 45°. The basement block here under form Structural relief of font eight
162:05 and length to width ratios of With the largest uplifted box being of
162:12 km long, So many of km and 300 km long. So very
162:18 sized structures. The tectonic setting of limited basement corridor. We think they're
162:27 by a flat slab subduction where the on plate, mm hmm, was
162:36 at a very long angle transmitting stresses . The lower crust here causing crustal
162:43 far inboard of the actual convergent Stern. That being said, the
162:59 direction of the individual structures vary significantly the east northeast convergence that we expect
163:07 the severe letter might thrust belt and convergence of the Federal line in the
163:11 American place, things like the N. To uplift here strike actually
163:19 to the convergence direction of the place the full thrust belt here elsewhere.
163:24 basement uplifts occur at a variety of on not strictly consistent with shortening in
163:32 east west direction. Here's a seismic from Casper, our experience in central
163:47 hanging wall here, football here, here and the football of the
163:53 We often see these apparently declines that really artifacts of of the velocity pull
164:00 caused by thrusting fast philosophy, basement the slow velocity velocity sentiments and so
164:08 like this were drilled and the anticipation there would be real structures down
164:18 the Pennsylvanian, permian ancestral rocky mountain are basement caught up with just like
164:23 labrum octuplets. Right? And we them shown here by the different college
164:30 and they include the Anadarko Ardmore basin here, the Arbuckle mountain here,
164:36 monster arch in north texas here in central basin platform here in the middle
164:41 the Permian basin. Looking at cross of the central basin platform. We
164:53 at cross sections along here, here's central basin platform where it's uplifted here's
165:00 eastern flank of the northern Delaware basin these cross sections across here. Sure
165:08 this space and margins are low to or reverse falls and try share foals
165:16 form at the crest of the just like we see and they will
165:20 mind rocky mountains. The helpless here's restore herbal section of one of these
165:34 . You see the hanging wall Football here, main structure forming falls
165:40 . The fault dies out into the of the fold here in this limb
165:46 get these verticals overturned beds as a of Tricia deformation within the tri shears
165:54 of this fall propagating upward. The cover contact here is the same dip
166:01 it is here. There's no rotation the hanging wall relative of the football
166:06 telling us that this fault has to plane. And the basement here in
166:13 is essentially on reform. Mm Here's an example from the central basin
166:25 example now from the ancestral rockies, the same kind of structure uplifted basin
166:31 here Fault dipping at about 45 degrees , little or no rotation of the
166:38 wall block relative to the football Telling us that this fault has to
166:42 planned steeply dipping to overlay turned limbs as a result of price shear deformation
166:49 the tip of his fault as it up in in the section and no
166:55 deformation of either the football or the wall beds outside this sign of Tricia
167:05 . Okay, so that the hanging geometries. Father with the same kind
167:12 rules we talked about earlier for for relations from where there's no tilt of
167:20 hanging wall relative of football. That we have to have a planer.
167:26 where we have this kind of where have this counter clockwise rotation of the
167:32 wall relative to the football is telling we have to have this concave of
167:37 shape fall. Conversely, where we a concave downward shape fall, we're
167:44 to get this counterclockwise rotation of the on relative to the football and then
167:51 detail faults. The basement falls. these complex geometries where we have a
167:57 concave all right up shaped fault And a plane or fault or low
168:05 dipping fault here, as the hanging moves across from here to here.
168:11 it starts to go up this we're gonna generate areas of local compression
168:16 , generating faults and folds and more faults here. Second order structures when
168:22 starts to go flat out of the here, we'll get these normal faults
168:26 local extension of structures. So within base concord out left, we'll see
168:31 variety of structures reflecting this geometry of underlying fault. And these alternative models
168:48 these basement product list straightforward enough, forwards are inherently unrestored herbal and not
168:55 double. So these are just geologically in both of these. The lights
169:02 the deformed beds in the cover are longer than the length of the basement
169:07 . Contact here, so these are under formidable unrestored herbal interpretations. So
169:19 slip faults in structures. The last of structure we talked about strike slip
169:25 this morning, which the movement of fall. What is more or less
169:29 to the strike of the fall. tip of the fault is vertical,
169:34 strike slip fault refers to the general of faults that can be any
169:42 We have rent, strike slip faults there are large, deep rooted falls
169:48 the crust transform falls where we have bounding strike slip falls that cut through
169:55 atmosphere and separate different spreading centers. faults which are lateral ramps and blink
170:03 that connect transfer between adjacent and overlapping false segments their faults and compensating differential
170:13 or a position of thrust faults or faults in a in the hanging wall
170:20 . And then we get different types strike slip structures in the overlying
170:25 we get these initial unfolds along the themselves. We get restraining bends with
170:32 compression will step across the folds. get releasing bands where there is an
170:37 of step across the floors. But between you get these domino style rotated
170:42 blocks and, lastly where we have element of compression. In addition to
170:50 slip, we get trans presage structures positive flower structures. Conversely, where
170:56 have a component of extension, we these trans dimensional structures or negative flower
171:07 . So strike slip faults and It's important to recognize them. The
171:12 slip faults. Both signal one and three are horizontal, But they are
171:16 at 30° to the vertical strikes that . And so signal one will be
171:23 at 30 degrees sigma three will be at 60 degrees to that particular
171:31 Right. And then we have the focal plane solutions where um we plot
171:42 first motions as on the lower hemisphere . We plot both the pressure and
171:50 tensile first arrivals of their infrequent The pressure arrivals correspond to the
171:58 Axis of the pressure access and the . One access. The tensile components
172:04 to the The tension or the three minimum strain. First arrivals.
172:11 plotting those on the lower hemisphere of , We divide the lower hemisphere into
172:16 quadrants mm hmm Where signal one represents area of compression. All first
172:24 single one will be in this Sigma three will be in this orientation
172:31 these nodal planes separating the different quadrants to potential fault planes with a sigma
172:39 in this orientation, we could have right a right lateral strikes at fault
172:45 . Or we could have a left strike slip fault here and so once
172:52 have these focal plane solutions, we to compare the nodal planes from these
172:59 plane solutions to the geology To see the sense of displacement is on the
173:10 and this shows the focal plane solutions different types of earthquakes. First strike
173:16 , We get these these four quarters very good normal planes for thrust
173:23 We get these moderately and steeply dipping planes with the compression. All access
173:30 to some horizontal with normal focal We get compression all focal solution.
173:40 near vertical with moderately to steeply dipping planes representing potential normal falls,
173:53 lateral and right lateral, left lateral where three term full block adjacent team
174:01 moved to your left. It's also a sinister role structure. Footfall.
174:07 strike slip fault is the opposite where block across where you're standing is moved
174:12 the right in a relative sense that's referred to as a dust, real
174:16 slip form, mm hmm. And important to separate apparent to differentiate apparent
174:26 from real strikes, look different. structural deformation here we have a scum
174:34 map outline with a horizontal separation of marker bed, but in fact,
174:41 have a normal fault when the trace , fault dipping here, this bed
174:48 here to the to the south. this horizontal separation, it was generated
174:55 dip slopes, dip slip displacement along normal faults here. So when we
175:01 these apparent separations, it's important to at the faulty geometry in the false
175:08 to understand whether these are true strike deformation or apparent separations representing resulting from
175:15 platforms restraining and releasing bands. So we've got an example of right lateral
175:24 slip fault here, it makes a to the right and as this block
175:31 away, it's going to open up releasing bend here which will be the
175:36 of normal false lakes semifinal structures, lows here you have a restraining where
175:46 movement of the faults. Mhm creates compression component across the falls here and
175:53 will generate an appliance, reverse faults structural highs at this location. Um
176:09 Mhm strain with progressive deformation, it us a strange lips like this that
176:16 put in that slide. Yes, go to this one. So with
176:20 progressive deformation you get increasing strain increasing of the strain of lips from this
176:27 this and um you get these folds incline simply unclear has developed parallel to
176:37 long axis of the strain of lips to the compression occurring perpendicular to the
176:43 of lips. And you get extension faults forming the extension, all part
176:48 the strain of lips reflecting the extension this direction due to the strikes of
176:55 . And these will rotate with progressive and potentially be over printed by subsequent
177:06 . Alright, that gets us to initial unfolds related to strikes defaulting in
177:14 ah the right slip case like we get an initial unfolds with this
177:20 relative to the strike slip deformation and reflecting the. uh huh. It's
177:28 turning the strain of Lips 90°. So offsets krill these offsets in this compression
177:37 fold section will equal these initial unfolds here with an opposite sense of
177:44 We get the opposite sense of initial with left lateral displacement here, get
177:50 initial unfolds in this orientation relative to overall displacement. And this is an
178:00 of the national unfolds and outcrop where see the full taxis here and
178:07 W plunging and inclines representing strain ellipses a long access in this orientation resulting
178:16 an underlying basement fault with the right sense of displacement aligned and then
178:27 positive and negative flower structures. These where we have a component of compression
178:34 extension in addition to the strikes So here we've got a right lateral
178:42 with essentially a restraining bend here and compression component across it. It gives
178:48 this pop up structure or positive flower here. Same sense of displacement but
178:55 different then in the fall equivalent to releasing bend in the fall that generates
179:01 of structures and gives us these negative structures. Okay, so strike slip
179:15 are commonly misinterpreted or confused with other of structures. We need to look
179:21 the orientations of the secondary structures. ensure that we're looking at strike slip
179:28 . Mhm. In evidence or strike will be thickness and theses changes changes
179:34 fall geometries and it really needs to confirmed in all three dimensions and then
179:42 complaint mechanisms that strikes the beach ball here. The grunting remembers that the
179:49 quadrants represent the orientation of. Of one the nodal planes separating the white
179:55 black clients represent the orientations of potential . And so to relate these to
180:04 , we need to take a formal tuitions and compare them to the faults
180:08 we see in in our crop to whether this represents a left lateral strike
180:15 fault or a right lateral strike slip . All right. So the exam
180:24 be Wednesday Wednesday evening 6-9. It cover all these topics, false
180:30 salt tectonics, all the full thrust things that we talked about. Strike
180:35 structures, basement cord uplifts, And it will represent about it'll represent
180:42 of the final grade. It'll be online virtual test, just like the
180:47 one. Multiple short answers at the of the at the start of the
180:52 session. I will email you the and you can you will be able
180:58 write on it, do whatever you with it and then email it back
181:03 me when you're finished and that will the end of the class. All
181:09 , sorry to interrupt and I'll send new link for the final early next
181:19 . Yeah, we we we don't a link so jay will have to
181:23 us all a link for that. , ready looking forward to it.
181:38 is this is a lot of materials cover. This is like people
181:43 drinking from the firehose. This is incredible amount of information. Um So
181:50 the test, I'll try and cover all, but it at a very
181:53 level to make sure you get the concepts, but not worry too much
181:58 all the details. Yes, Thank you sir. All right.
182:06 welcome. Thank you very much, the rest of the weekend and we'll
182:10 you Wednesday evening. Thank you. you. Bye
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