Mechanical relationship between strike-slip faulting and salt tectonics in the Northern Tunisian Atlas: The Bir-El-Afou salt structure

2021 ◽  
pp. 104501
Author(s):  
Zayneb Amri ◽  
Amara Masrouhi ◽  
Chahreddine Naji ◽  
Olivier Bellier ◽  
Hemin Koyi
Keyword(s):  
Strike Slip ◽  
Salt Tectonics ◽  
Salt Structure ◽  
Tunisian Atlas

Halokinetic analysis of the Frade field area, Campos Basin, Brazil: Salt tectonics within an offshore strike-slip setting

2020 ◽  
Vol 8 (4) ◽  
pp. T869-T883
Author(s):  
Stephanie Wischer ◽  
Webster Mohriak
Keyword(s):  
Strike Slip ◽  
Oil Field ◽  
Salt Diapir ◽  
Salt Tectonics ◽  
Tectonic Structures ◽  
Complex Deformation ◽  
Pull Apart Basin ◽  
Campos Basin ◽  
Salt Structure ◽  
3D Volume

The Frade field, located within the Campos Basin in the southeastern Brazilian margin, is a key oil field that produces from Oligo-Miocene turbidite reservoirs that derived their structural positioning due to the presence of an underlying salt diapir. The evolution of the Frade salt structure was examined using well data, selected 2D lines, and a 3D volume that were interpreted in detail focusing on the Aptian evaporite interval and its influence on the overburden. Analysis of the salt-sediment interaction indicated a complex deformation history that included five main stages of deformation, some assisted by tectonic reactivation episodes. (1) Post-Albian reactivation of a nearby north–northwest-south–southeast basement fault caused the Albian carbonate interval to fault, forming a west–northwest-east–southeast shear zone with a dextral strike-slip component. This movement initiated thin-skinned tectonics that offset the Albian carbonates and formed a pull-apart basin that accommodated a thick Late Cretaceous interval, which weakened the overburden and allowed for the initial formation of the Frade salt diapir. (2) Renewed diapir growth thickened and redistributed the Cenomanian-Maastrichtian sedimentary package proximal to the Frade salt anticline. (3) An initial and localized collapse of the Frade salt anticline occurred during early Paleogene extension. (4) Paleogene shortening caused the salt to flow, resulting in salt withdrawal in the southeast and diapir rejuvenation near its present-day apex, forming several inversion structures. In addition, the Paleogene shortening resulted in a low-relief anticlinal structure that rotated the turbidites into geometries favoring hydrocarbon accumulation. (5) A return to an extensional regime occurred during the late Oligocene/early Miocene. The results of this study provide a new insight into the development of strike-slip salt tectonic structures and show for the first time within the Campos Basin an Albian-level pull-apart basin that formed in association with salt tectonics.

Interplay of thrust, back-thrust, strike-slip and salt tectonics in a fold and thrust belt system: an example from Zakynthos Island, Greece

2016 ◽  
Vol 105 (7) ◽  
pp. 2111-2132 ◽  
Author(s):  
A. Zelilidis ◽  
G. Papatheodorou ◽  
A. G. Maravelis ◽  
D. Christodoulou ◽  
P. Tserolas ◽  
...  
Keyword(s):  
Strike Slip ◽  
Salt Tectonics ◽  
Thrust Belt ◽  
Fold And Thrust Belt ◽  
Belt System

On the Faceting of Polar Ceramic Surfaces: Microscopy and Holography Studies of MGO(111) Surfaces

1996 ◽  
Vol 54 ◽  
pp. 366-367
Author(s):  
M. Gajdardziska-Josifovska ◽  
B. G. Frost ◽  
E. Völkl ◽  
L. F. Allard
Keyword(s):  
Electron Microscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Electron Holography ◽  
Flat Surfaces ◽  
Transmission Electron ◽  
Excess Surface ◽  
Polar Surfaces ◽  
Salt Structure ◽  
Crystallographic Planes

Polar surfaces are those crystallographic faces of ionically bonded solids which, when bulk terminated, have excess surface charge and a non-zero dipole moment perpendicular to the surface. In the case of crystals with a rock salt structure, {111} faces are the exemplary polar surfaces. It is commonly believed that such polar surfaces facet into neutral crystallographic planes to minimize their surface energy. This assumption is based on the seminal work of Henrich which has shown faceting of the MgO(111) surface into {100} planes giving rise to three sided pyramids that have been observed by scanning electron microscopy. These surfaces had been prepared by mechanical polishing and phosphoric acid etching, followed by Ar+ sputtering and 1400 K annealing in ultra-high vacuum (UHV). More recent reflection electron microscopy studies of MgO(111) surfaces, annealed in the presence of oxygen at higher temperatures, have revealed relatively flat surfaces stabilized by an oxygen rich reconstruction. In this work we employ a combination of optical microscopy, transmission electron microscopy, and electron holography to further study the issue of surface faceting.

Twin Boundary in Bechgaard Salt: Structure and Unusual Dynamics

1996 ◽  
Vol 6 (12) ◽  
pp. 1567-1574 ◽  
Author(s):  
M. Mukoujima ◽  
K. Kawabata ◽  
T. Sambongi
Keyword(s):  
Twin Boundary ◽  
Salt Structure ◽  
Bechgaard Salt

Failure Analysis Of Buried Gas Pipelines Crossing Seismic Faults

2020 ◽  
Vol 3 (2) ◽  
pp. 781-790
Author(s):  
M. Rizwan Akram ◽  
Ali Yesilyurt ◽  
A.Can. Zulfikar ◽  
F. Göktepe
Keyword(s):  
Ground Deformation ◽  
Warning System ◽  
Strike Slip ◽  
Gas Pipelines ◽  
Steel Pipes ◽  
Seismic Fault ◽  
Fault Parameters ◽  
Dip Angle ◽  
Permanent Ground Deformation ◽  
Recent Earthquakes

Research on buried gas pipelines (BGPs) has taken an important consideration due to their failures in recent earthquakes. In permanent ground deformation (PGD) hazards, seismic faults are considered as one of the major causes of BGPs failure due to accumulation of impermissible tensile strains. In current research, four steel pipes such as X-42, X-52, X-60, and X-70 grades crossing through strike-slip, normal and reverse seismic faults have been investigated. Firstly, failure of BGPs due to change in soil-pipe parameters have been analyzed. Later, effects of seismic fault parameters such as change in dip angle and angle between pipe and fault plane are evaluated. Additionally, effects due to changing pipe class levels are also examined. The results of current study reveal that BGPs can resist until earthquake moment magnitude of 7.0 but fails above this limit under the assumed geotechnical properties of current study. In addition, strike-slip fault can trigger early damage in BGPs than normal and reverse faults. In the last stage, an early warning system is proposed based on the current procedure. 

Zircon geochronology and paleomagnetism of an Archean harzburgite intrusion, eastern Bighorn Mountains, Wyoming

2020 ◽  
Vol 57 (1) ◽  
pp. 21-40
Author(s):  
Alexandra Wallenberg ◽  
Michelle Dafov ◽  
David Malone ◽  
John Craddock
Keyword(s):  
Hanging Wall ◽  
Vertical Axis ◽  
Shear Zones ◽  
Strike Slip ◽  
Zircon Geochronology ◽  
Weighted Mean ◽  
Mafic Complex ◽  
Laramide Orogeny ◽  
Axis Rotation ◽  
Bighorn Mountains

A harzburgite intrusion, which is part of the trailside mafic complex) intrudes ~2900-2950 Ma gneisses in the hanging wall of the Laramide Bighorn uplift west of Buffalo, Wyoming. The harzburgite is composed of pristine orthopyroxene (bronzite), clinopyroxene, serpentine after olivine and accessory magnetite-serpentinite seams, and strike-slip striated shear zones. The harzburgite is crosscut by a hydrothermally altered wehrlite dike (N20°E, 90°, 1 meter wide) with no zircons recovered. Zircons from the harzburgite reveal two ages: 1) a younger set that has a concordia upper intercept age of 2908±6 Ma and a weighted mean age of 2909.5±6.1 Ma; and 2) an older set that has a concordia upper intercept age of 2934.1±8.9 Ma and a weighted mean age 2940.5±5.8 Ma. Anisotropy of magnetic susceptibility (AMS) was used as a proxy for magmatic intrusion and the harzburgite preserves a sub-horizontal Kmax fabric (n=18) suggesting lateral intrusion. Alternating Field (AF) demagnetization for the harzburgite yielded a paleopole of 177.7 longitude, -14.4 latitude. The AF paleopole for the wehrlite dike has a vertical (90°) inclination suggesting intrusion at high latitude. The wehrlite dike preserves a Kmax fabric (n=19) that plots along the great circle of the dike and is difficult to interpret. The harzburgite has a two-component magnetization preserved that indicates a younger Cretaceous chemical overprint that may indicate a 90° clockwise vertical axis rotation of the Clear Creek thrust hanging wall, a range-bounding east-directed thrust fault that accommodated uplift of Bighorn Mountains during the Eocene Laramide Orogeny.

Tracking dinosaurs in BLM canyon country, Utah

2018 ◽  
Vol 3 ◽  
pp. 67-100 ◽  
Author(s):  
ReBecca K. Hunt-Foster ◽  
Martin G. Lockley ◽  
Andrew R.C. Milner ◽  
John R. Foster ◽  
Neffra A. Matthews ◽  
...  
Keyword(s):  
Colorado Plateau ◽  
Foreland Basin ◽  
Salt Tectonics ◽  
Initial Development ◽  
Paradox Basin ◽  
Cedar Mountain Formation ◽  
History Of ◽  
San Rafael ◽  
San Rafael Swell ◽  
Biological History

Although only recognized as a discrete stratigraphic unit since 1944, the Cedar Mountain Formation represents tens of millions of years of geological and biological history on the central Colorado Plateau. This field guide represents an attempt to pull together the results of recent research on the lithostratigraphy, chronostratigraphy, sequence stratigraphy, chemostratigraphy, and biostratigraphy of these medial Mesozoic strata that document the dynamic and complex geological history of this region. Additionally, these data provide a framework by which to examine the history of terrestrial faunas during the final breakup of Pangaea. In fact, the medial Mesozoic faunal record of eastern Utah should be considered a keystone in understanding the history of life across the northern hemisphere. Following a period of erosion and sediment bypass spanning the Jurassic–Cretaceous boundary, sedimentation across the quiescent Colorado Plateau began during the Early Cretaceous. Thickening of these basal Cretaceous strata across the northern Paradox Basin indicate that salt tectonics may have been the predominant control on deposition in this region leading to the local preservation of fossiliferous strata, while sediment bypass continued elsewhere. Thickening of overlying Aptian strata west across the San Rafael Swell provides direct evidence of the earliest development of a foreland basin with Sevier thrusting that postdates geochemical evidence for the initial development of a rain shadow.

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