scholarly journals Modelling role of basement block rotation and strike-slip faulting on structural pattern in cover units of fold-and-thrust belts

2016 ◽  
Vol 153 (5-6) ◽  
pp. 827-844 ◽  
Author(s):  
HEMIN KOYI ◽  
FARAMARZ NILFOUROUSHAN ◽  
KHALED HESSAMI
Keyword(s):  
Vertical Axis ◽  
Strike Slip ◽  
Block Rotation ◽  
Northern Iran ◽  
Fault Movement ◽  
Structural Pattern ◽  
Basement Faults ◽  
Thrust Belts ◽  
Basement Fault ◽  
Southwestern Iran

AbstractA series of scaled analogue models are used to study (de)coupling between basement and cover deformation. Rigid basal blocks were rotated about a vertical axis in a ‘bookshelf’ fashion, which caused strike-slip faulting along the blocks and in the overlying cover units of loose sand. Three different combinations of cover–basement deformations are modelled: (i) cover shortening before basement fault movement; (ii) basement fault movement before cover shortening; and (iii) simultaneous cover shortening with basement fault movement. Results show that the effect of the basement faults depends on the timing of their reactivation. Pre- and syn-orogenic basement fault movements have a significant impact on the structural pattern of the cover units, whereas post-orogenic basement fault movement has less influence on the thickened hinterland of the overlying belt. The interaction of basement faulting and cover shortening results in the formation of rhombic structures. In models with pre- and syn-orogenic basement strike-slip faults, rhombic blocks develop as a result of shortening of the overlying cover during basement faulting. These rhombic blocks are similar in appearance to flower structures, but are different in kinematics, genesis and structural extent. We compare these model results to both the Zagros fold-and-thrust belt in southwestern Iran and the Alborz Mountains in northern Iran. Based on the model results, we conclude that the traces of basement faults in cover units rotate and migrate towards the foreland during regional shortening. As such, these traces do not necessarily indicate the actual location or orientation of the basement faults which created them.

Accommodation of India–Asia convergence via strike-slip faulting and block rotation in the Qilian Shan fold–thrust belt, northern margin of the Tibetan Plateau

2021 ◽  
pp. jgs2020-207
Author(s):  
Feng Cheng ◽  
Andrew V. Zuza ◽  
Peter J. Haproff ◽  
Chen Wu ◽  
Christina Neudorf ◽  
...  
Keyword(s):  
Strike Slip ◽  
Luminescence Dating ◽  
Thrust Belt ◽  
Block Rotation ◽  
Content Type ◽  
Link Type ◽  
Northeastern Tibet ◽  
Thrust Belts ◽  
Fold And Thrust Belts ◽  
Supplementary Material

Existing models of intracontinental deformation have focused on plate-like rigid body motion v. viscous-flow-like distributed deformation. To elucidate how plate convergence is accommodated by intracontinental strike-slip faulting and block rotation within a fold–thrust belt, we examine the Cenozoic structural framework of the central Qilian Shan of northeastern Tibet, where the NW-striking, right-slip Elashan and Riyueshan faults terminate at the WNW-striking, left-slip Haiyuan and Kunlun faults. Field- and satellite-based observations of discrete right-slip fault segments, releasing bends, horsetail termination splays and off-fault normal faulting suggest that the right-slip faults accommodate block rotation and distributed west–east crustal stretching between the Haiyuan and Kunlun faults. Luminescence dating of offset terrace risers along the Riyueshan fault yields a Quaternary slip rate of c. 1.1 mm a−1, which is similar to previous estimates. By integrating our results with regional deformation constraints, we propose that the pattern of Cenozoic deformation in northeastern Tibet is compatible with west–east crustal stretching/lateral displacement, non-rigid off-fault deformation and broad clockwise rotation and bookshelf faulting, which together accommodate NE–SW India–Asia convergence. In this model, the faults represent strain localization that approximates continuum deformation during regional clockwise lithospheric flow against the rigid Eurasian continent.Supplementary material: Luminescence dating procedures and protocols is available at https://doi.org/10.17605/OSF.IO/CR9MNThematic collection: This article is part of the Fold-and-thrust belts and associated basins collection available at: https://www.lyellcollection.org/cc/fold-and-thrust-belts

Albian syndepositional block rotation and its geological consequences, Basque–Cantabrian Basin (western Pyrenees)

2013 ◽  
Vol 150 (6) ◽  
pp. 986-1001 ◽  
Author(s):  
LUIS MIGUEL AGIRREZABALA ◽  
JAUME DINARÈS-TURELL
Keyword(s):  
Slip Rate ◽  
Vertical Axis ◽  
Strike Slip ◽  
Block Rotation ◽  
Minimum Block ◽  
Magmatic Intrusions ◽  
Axis Rotation ◽  
High Level ◽  
Basque Cantabrian Basin ◽  
Dextral Strike Slip

AbstractStratigraphic, structural, palaeocurrent and palaeomagnetic analyses of Upper Albian deep-water deposits in and around the Deba block (Northern Iberia) are presented. Results indicate an anticlockwise vertical-axis rotation of this block by 35° during a maximum time span of c. 1 Ma (Late Albian intra-C. auritus ammonite Subzone). This Albian syndepositional block rotation is interpreted to be the consequence of the coeval activity of conjugate major sinistral strike-slip faults and minor (antithetic) dextral strike-slip faults, which border the Deba block. On the base of conservative estimations, a minimum block-rotation rate of 35° Ma−1 and a sinistral strike-slip rate of 1.2 km Ma−1 are calculated. As a consequence of the interaction of the rotated Deba block with adjacent non-rotated blocks, its corners experienced coeval transpressive (NW and SE corners) and transtensional deformations (SW and, possibly, NE corners). At the transtensional SW corner, two domal high-reflective seismic structures have been recorded and interpreted as high-level magmatic laccoliths. These magmatic intrusions triggered the development of a mineralizing hydrothermal system, which vented to the Late Albian seafloor warm to hot hydrocarbon-rich fluids. Vented hydrocarbon was generated from Albian organic-rich sediments by contact alteration with hydrothermal fluids.

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.

Interpretation of aeromagnetic data to detect the deep-seated basement faults in fold thrust belts: NW part of the petroliferous Fars province, Zagros belt, Iran

2021 ◽  
pp. 105292
Author(s):  
Raana Razavi-Pash ◽  
Zeinab Davoodi ◽  
Soumyajit Mukherjee ◽  
Leila Hashemi-Dehsarvi ◽  
Tahereh Ghasemi-Rozveh
Keyword(s):  
Fars Province ◽  
Aeromagnetic Data ◽  
Basement Faults ◽  
Thrust Belts

scholarly journals Stretching and Contraction of Extensional Basins With Pre-Rift Salt: A Numerical Modeling Approach

2021 ◽  
Vol 9 ◽  
Author(s):  
Pablo Granado ◽  
Jonas B. Ruh ◽  
Pablo Santolaria ◽  
Philipp Strauss ◽  
Josep Anton Muñoz
Keyword(s):  
Hanging Wall ◽  
Structural Evolution ◽  
Extension Rate ◽  
Rift Basins ◽  
Basin Inversion ◽  
Accommodation Space ◽  
Basement Faults ◽  
Original Distribution ◽  
Thrust Belts ◽  
Half Graben

We present a series of 2D thermo-mechanical numerical experiments of thick-skinned crustal extension including a pre-rift salt horizon and subsequent thin-, thick-skinned, or mixed styles of convergence accompanied by surface processes. Extension localization along steep basement faults produces half-graben structures and leads to variations in the original distribution of pre-rift salt. Thick-skinned extension rate and salt rheology control hanging wall accommodation space as well as the locus and timing of minibasin grounding. Upon shortening, extension-related basement steps hinder forward propagation of evolving shallow thrust systems; conversely, if full basin inversion takes place along every individual fault, the regional salt layer is placed back to its pre-extensional configuration, constituting a regionally continuous décollement. Continued shortening and basement involvement deform the shallow fold-thrust structures and locally breaches the shallow décollement. We aim at obtaining a series of structural, stratigraphic and kinematic templates of fold-and-thrust belts involving rift basins with an intervening pre-rift salt horizon. Numerical results are compared to natural cases of salt-related inversion tectonics to better understand their structural evolution.

Aftershocks of the Benham nuclear explosion

1969 ◽  
Vol 59 (6) ◽  
pp. 2271-2281
Author(s):  
R. M. Hamilton ◽  
J. H. Healy
Keyword(s):  
Fault Plane ◽  
Nuclear Explosion ◽  
Test Site ◽  
Strike Slip ◽  
Nevada Test Site ◽  
Ground Zero ◽  
Fault Plane Solutions ◽  
Fault Movement ◽  
Near Surface ◽  
Earthquake Distribution

abstract The Benham nuclear explosion, a 1.1 megaton test 1.4 km beneath Pahute Mesa at the Nevada Test Site, initiated a sequence of earthquakes lasting several months. The epicenters of these shocks were located within 13 km of ground zero in several linear zones that parallel the regional fault trends. Focal depths range from near surface to 6 km. The earthquakes are not located in the zone of the major ground breakage. The earthquake distribution and fault plane solutions together indicate that both right-lateral strike-slip fault movement and dip-slip fault movement occurred. The explosion apparently caused the release of natural tectonic strain.

‘Plains-Type Folds’ in the Midcontinent Region (U.S.A.): Chronicling A Concept

1999 ◽  
Vol 18 (2) ◽  
pp. 264-294 ◽  
Author(s):  
D. Merriam
Keyword(s):  
Twentieth Century ◽  
Crystalline Basement ◽  
Areal Extent ◽  
Structural Pattern ◽  
Sediment Compaction ◽  
The World ◽  
Basement Fault ◽  
Midcontinent Usa

‘Plains-type folds’ are those folds formed in gently dipping sediments overlying a crystalline basement in cratonic areas of the world. They are the result of differential compaction of sediments over rigid basement fault blocks. Trends of the folds in the sedimentary section thus coincide with trends of basement features. Plains-type folds generally are (1) small in areal extent, (2) increase in closure downward, (3) without a corresponding depression, and (4) asymmetric and associated with faulting. The features were developed intermittently through time by differential compaction of the sediments over an inherent structural pattern of uplifted fault blocks in the basement. Plains-type folds were recognized early in the twentieth century in the Midcontinent (USA) as containing petroleum. They were the object of much speculation on their origin and development and were studied intensively in the 1920s and 1930s. Most of the studies were concentrated in Kansas and Oklahoma and revolved around the relation of the structures as mapped in the sediments to the configuration of the Precambrian crystalline basement, relation of structure and temperature, and the effect of sediment compaction over ‘buried hills.’

Distributed strike-slip faulting, block rotation and possible intracrustal vertical decoupling in the convergent zone of SW Japan

2004 ◽  
Vol 227 (1) ◽  
pp. 141-165 ◽  
Author(s):  
Olivier Fabbri ◽  
Kazumasa Iwamura ◽  
Satoshi Matsunaga ◽  
Guilhem Coromina ◽  
Yuji Kanaori
Keyword(s):  
Strike Slip ◽  
Block Rotation ◽  
Sw Japan
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