Spatio-temporal structural evolution of the Kohat fold and thrust belt of Pakistan

2021 ◽  
Vol 145 ◽  
pp. 104310
Author(s):  
Humaad Ghani ◽  
Edward R. Sobel ◽  
Gerold Zeilinger ◽  
Johannes Glodny ◽  
Irum Irum ◽  
...  
Keyword(s):  
Structural Evolution ◽  
Thrust Belt ◽  
Fold And Thrust Belt ◽  
Spatio Temporal

The pre-Mesozoic basement underneath the Jura Mountains fold-and-thrust belt: an overview from models and maps

2020 ◽  
Author(s):  
Marc Schori ◽  
Anna Sommaruga ◽  
Jon Mosar
Keyword(s):  
Cross Sections ◽  
Structural Evolution ◽  
Rift System ◽  
European Alps ◽  
Thrust Belt ◽  
Jura Mountains ◽  
Basement Faults ◽  
Fold And Thrust Belt ◽  
Spatio Temporal ◽  
Basement Structures

<p>The Jura Mountains are a thin-skinned fold-and-thrust belt (FTB) in the northern foreland of the European Alps, extending over northern and western Switzerland and eastern France. The Jura FTB was detached in Triassic evaporites during Late Miocene and Pliocene compression. Prior to this, the pre-Mesozoic basement was intensely pre-structured by inherited faults that had been reactivated under changing stress fields during the Mesozoic and Cenozoic structural evolution of continental Europe. In order to understand the connection between thin-skinned FTB formation and pre-existing basement structures, we compiled boreholes and geological cross-sections across the Northern Alpine Foreland and derived elevation, thickness and erosion models of defined Mesozoic units and the top of the pre-Mesozoic basement.</p><p>Our models confirm the presence of basement faults concealed underneath the detached cover of the Jura Mountains. The pre-Mesozoic basement shows differences in structural altitudes resulting from partially overlapping lithospheric processes. They include graben formation during evolution of the European Cenozoic Rift System (ECRIS), flexural subsidence during Alpine forebulge development and lithospheric long-wavelength buckle folding. Faults in connection with these processes follow structural trends that suggest the reactivation of inherited Variscan and post-Variscan fault systems. We discuss the spatio-temporal imprint of lithospheric signatures on the pre-Mesozoic basement and their consequence on the formation of the Jura Mountains FTB. Untangling structures within the pre-Mesozoic basement leads us to a modern understanding of the long-term evolution of the detached Mesozoic cover. Furthermore, it allows us to improve the prediction of ages that are potentially preserved within the Mesozoic cover of the Jura FTB.</p>

Structure of the Gare Kakheti foothills using seismic reflection profiles: implications for kinematic evolution of the Georgian part of Kura foreland fold-and-thrust belt

2020 ◽  
Author(s):  
Alexander Razmadze
Keyword(s):  
Cross Sections ◽  
Seismic Reflection ◽  
Structural Evolution ◽  
Foreland Basin ◽  
Thrust Belt ◽  
Fault Propagation ◽  
Seismic Reflection Data ◽  
Growth Strata ◽  
Kinematic Evolution ◽  
Fold And Thrust Belt

<p>Gare Kakheti foothills are located between Lesser Caucasus and Kakheti Ridge and are mainly represented by the series of NEN dipping thrust faults, most of which are associated with fault‐related folds. Gare Kakheti foothills as a part of the Kura foreland fold-and-thrust belt developed formerly as a foreland basin (Oligocene-Lower Miocene) (e.g. Alania et al., 2017). Neogene shallow marine and continental sediments in the Gare Kakheti foothills keep the record on the stratigraphy and structural evolution of the study area during the compressive deformation. Interpreted seismic profiles and structural cross-sections across the Udabno, Tsitsmatiani, and Berebisseri synclines show that they are thrust-top basins. Seismic reflection data reveal the presence of growth fault-propagation folds and some structural wedges (or duplex). The evolution of the Udabno, Tsitsmatiani, and Berebisseri basins is compared with simple models of thrust-top basins whose development is controlled by the kinematics of competing for growth anticlines. Growth anticlines are mainly represented by fault-propagation folds. The geometry of growth strata in associated footwall synclines and the sedimentary infill of thrust-top basins provide information on the thrusting activity in terms of location, geometry, and age.<br>This work was supported by Shota Rustaveli National Science Foundation (SRNSF - #PHDF-19-268).</p><p> </p>

Integrated Cretaceous–Cenozoic plate tectonics and structural geology in southern Mexico

2020 ◽  
pp. SP504-2020-70
Author(s):  
Rod Graham ◽  
James Pindell ◽  
Diego Villagómez ◽  
Roberto Molina-Garza ◽  
James Granath ◽  
...  
Keyword(s):  
Cross Sections ◽  
Tectonic Evolution ◽  
Plate Tectonics ◽  
Plate Boundary ◽  
Structural Evolution ◽  
Thrust Belt ◽  
Cocos Plate ◽  
Southern Mexico ◽  
Arc Volcanism ◽  
Fold And Thrust Belt

AbstractThe structural evolution of southern Mexico is described in the context of its plate tectonic evolution and illustrated by two restored crustal scale cross-sections through Cuicateco and the Veracruz Basin and a third across Chiapas. We interpret the Late Jurassic–Early Cretaceous opening of an oblique hyper-stretched intra-arc basin between the Cuicateco Belt and Oaxaca Block of southern Mexico where Lower Cretaceous deep-water sediments accumulated. These rocks, together with the hyper-stretched basement beneath them and the Oaxaca Block originally west of them, were thrust onto the Cretaceous platform of the Cuicateco region during a Late Cretaceous–Eocene orogenic event. The mylonitic complex of the Sierra de Juárez represents this hyper-stretched basement, perhaps itself an extensional allochthon. The Chiapas fold-and-thrust belt is mainly Neogene in age. Shallowing of the subduction angle of the Cocos Plate in the wake of the Chortis Block, suggested by seismicity and migrating arc volcanism, is thought to play an important role in the development of the Chiapas fold-and-thrust belt itself, helping to explain the structural dilemma of a vertical transcurrent plate boundary fault (the Tonalá Fault) at the back of an essentially dip-slip fold-and-thrust belt.

The Role of Isostasy in the Evolution of Thin-Skinned Fold and Thrust Belt

2021 ◽  
Author(s):  
Youseph Ibrahim ◽  
Patrice Rey
Keyword(s):  
Numerical Experiments ◽  
Basal Layer ◽  
Structural Evolution ◽  
Geological Model ◽  
Thrust Belt ◽  
Isostatic Adjustment ◽  
Flexural Response ◽  
Thrust Belts ◽  
Fold And Thrust Belt ◽  
Fold And Thrust Belts

<p>The stacking of thrust sheets and mass transfer of sediment during fold and thrust belt accretion imposes a load on the basement and underlying mantle. This load induces an isostatic adjustment through a flexural response, which may also contribute to the overall architecture of the fold and thrust belt. Whereas plate kinematics imposes its tempo to evolving fold and thrust belts, the rheology of the mantle controls the tempo of the isostatic flexure. Using two-dimensional high-resolution numerical experiments, we explore how the interplay between the tectonic compressional rate and the isostatic flexural rate influences the structural evolution and final architecture of fold and thrust belts. </p><p>We run a suite of numerical experiments using the well-tested code Underworld. Our geological model is mapped over a 42 km by 16 km numerical grid, with a cell resolution of 80 m. The geological model consists from top to bottom of  ‘sticky air’, 4 km of sediment that alternates in competence at 500 m intervals, a 3 km thick basement, and a basal layer which - in combination with a basal kinematic boundary condition - controls the amount of isostatic flexure. Materials have a mechanical behavior that results from elasto-visco-plastic rheology. The pressure at the base of the model is held constant, and the vertical velocity is updated at each timestep. The amount of material entering or exiting the model at each point along the base scales with the density of the basal layer, which is used to control the isostatic rate. Sedimentation and erosion are self-consistent through mechanical erosion and a hillslope diffusion law. Our models show that as the ratio between tectonic and flexural rates decreases (i.e. flexure gets faster), fold and thrust belts become narrower, lower in elevation, and structurally more complex. We compare these results with natural analogs including the Cordilleran and Jura fold and thrust belts.</p>

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