scholarly journals Active strike-slip faults and an outer frontal thrust in the Himalayan foreland basin

2020 ◽  
Vol 117 (30) ◽  
pp. 17615-17621
Author(s):  
Michael J. Duvall ◽  
John W. F. Waldron ◽  
Laurent Godin ◽  
Yani Najman
Keyword(s):  
Foreland Basin ◽  
Historical Seismicity ◽  
Indian Plate ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Triangle Zone ◽  
Blind Thrust ◽  
Thrust Sheets ◽  
Himalayan Foreland Basin ◽  
Basement Ridge

The Himalayan foreland basin formed by flexure of the Indian Plate below the advancing orogen. Motion on major thrusts within the orogen has resulted in damaging historical seismicity, whereas south of the Main Frontal Thrust (MFT), the foreland basin is typically portrayed as undeformed. Using two-dimensional seismic reflection data from eastern Nepal, we present evidence of recent deformation propagating >37 km south of the MFT. A system of tear faults at a high angle to the orogen is spatially localized above the Munger-Saharsa basement ridge. A blind thrust fault is interpreted in the subsurface, above the sub-Cenozoic unconformity, bounded by two tear faults. Deformation zones beneath the Bhadrapur topographic high record an incipient tectonic wedge or triangle zone. The faults record the subsurface propagation of the Main Himalayan Thrust (MHT) into the foreland basin as an outer frontal thrust, and provide a modern snapshot of the development of tectonic wedges and lateral discontinuities preserved in higher thrust sheets of the Himalaya, and in ancient orogens elsewhere. We estimate a cumulative slip of ∼100 m, accumulated in <0.5 Ma, over a minimum slipped area of ∼780 km2. These observations demonstrate that Himalayan ruptures may pass under the present-day trace of the MFT as blind faults inaccessible to trenching, and that paleoseismic studies may underestimate Holocene convergence.

Proterozoic craton to basin crustal transition in western Canada and its influence on the evolution of the Cordillera

1991 ◽  
Vol 28 (8) ◽  
pp. 1148-1158 ◽  
Author(s):  
Frederick A. Cook ◽  
John L. Varsek ◽  
Elizabeth A. Clark
Keyword(s):  
Foreland Basin ◽  
Western Canada ◽  
Seismic Reflection Data ◽  
The North ◽  
Reflection Data ◽  
Sufficient Distance ◽  
Thrust Sheets ◽  
Alberta Basin ◽  
Mackenzie Mountains ◽  
Thin Crust

Deep seismic reflection data have imaged a crustal-scale, west-facing ramp or ramp system in the subsurface of western Canada. In northwestern Canada the ramp is within Proterozoic crust east of the Cordillera and is unconformably overlain by Paleozoic sedimentary rocks, indicating that it was formed during the Proterozoic in this region. Similar structures are visible within the Cordillera in southern Canada and the northwestern United States along a south projection of the ramp observed in the north. In the Monashee Complex of British Columbia and in the Priest River Complex in northern Washington, reflections are visible that dip westward from the surface to near the base of the crust and are structurally discordant with underlying more horizontal reflections, thus outlining footwall ramps. We propose that the Proterozoic crustal ramp in the north and the footwall ramps in the Cordillera probably coincide with a Proterozoic crustal transition from thick craton on the east to thin crust on the west. This transition may have influenced sedimentation patterns during deposition of Middle Proterozoic Belt–Purcell and Wernecke strata (ca. 1.6–1.3 Ga) and probably controlled the arcuate shape of the Mackenzie Mountains during their formation in the Mesozoic. This interpretation is consistent with the notion that thrust sheets of the Mackenzie Mountains did not extend onto the craton a sufficient distance to produce flexural subsidence of the thick crust and associated foreland basin development, whereas thrust sheets of the southern Canadian Cordillera were driven eastward and loaded the thick craton, causing crustal flexure and development of the Alberta Basin.

Structural initiation along the frontal fold-thrust system in the western Indo-Burman Range: Implications for the tectonostratigraphic evolution of the Hatia Trough (Bengal Basin)

2021 ◽  
pp. 1-25
Author(s):  
Rashed Abdullah ◽  
Md. Shahadat Hossain ◽  
Md. Soyeb Aktar ◽  
Md. Soyeb Aktar ◽  
Mohammad Moinul Hossain ◽  
...  
Keyword(s):  
Structural Complexity ◽  
Strike Slip ◽  
Indian Plate ◽  
Bengal Basin ◽  
Structural Development ◽  
Fold Belt ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Thrust System ◽  
Subduction System

The Bengal Basin accommodates an extremely thick Cenozoic sedimentary succession that derived from the uplifted Himalayan and Indo-Burman Orogenic Belts in response to the subduction of the Indian Plate beneath the Eurasian and Burmese plates. The Hatia Trough is a proven petroleum province that occupies much of the southern Bengal Basin. However, the style of deformation, kinematics, and possible timing of structural initiation in the Hatia Trough and the relationship of this deformation to the frontal fold-thrust system in the outer wedge (namely, the Chittagong Tripura Fold Belt) of the Indo-Burman subduction system to the east are largely unknown. Therefore, we carried out a structural interpretation across the eastern Hatia Trough and western Chittagong Tripura Fold Belt based on 2D seismic reflection data. Our result suggests that the syn-kinematic packages correspond to the Pliocene Tipam Group and Pleistocene Dupitila Formation. This implies that the structural development in the western Chittagong Tripura Fold Belt took place from the Pliocene. In the Hatia Trough, the timing of structural activation is slightly later (since the Plio-Pleistocene). In general, fold intensity and structural complexity gradually increase towards the east. The presence of reverse faults with minor strike-slip motion along the frontal thrust system in the outer wedge is also consistent with the regional transpressional structures of the Indo-Burman subduction system. However, to the west, there is no evidence for strike-slip deformation in the Hatia Trough. The restored sections show that the amount of E-W shortening in the Hatia Trough is very low (maximum 1.2%). In contrast, to the east, the amount of shortening is high (maximum 13.5%) in the western margin of the Chittagong Tripura Fold Belt. In both the areas, the key trapping mechanism includes anticlinal traps, although, stratigraphic and combinational traps are possible, but it requires further evaluation.

Indian plate structural inheritance in the Himalayan foreland basin, Nepal

2021 ◽  
Author(s):  
Michael J. Duvall ◽  
John W.F. Waldron ◽  
Laurent Godin ◽  
Yani Najman ◽  
Alex Copley
Keyword(s):  
Foreland Basin ◽  
Indian Plate ◽  
Structural Inheritance ◽  
Himalayan Foreland Basin

scholarly journals Active and recent deformation at the Southern Alps – Ligurian basin junction

2001 ◽  
Vol 80 (3-4) ◽  
pp. 255-272 ◽  
Author(s):  
C. Larroque ◽  
N. Béthoux ◽  
E. Calais ◽  
F. Courboulex ◽  
A. Deschamps ◽  
...  
Keyword(s):  
Western Europe ◽  
Active Faults ◽  
Southern Alps ◽  
Historical Seismicity ◽  
Data Set ◽  
Seismic Reflection Data ◽  
Geological Evidence ◽  
Reflection Data ◽  
Rate Versus ◽  
Ligurian Basin

AbstractThe Southern Alps – Ligurian basin junction is one of the most active seismic areas in Western Europe countries. The topographic and the structural setting of this region is complex because of (i) its position between the high topography of the Southern Alps and the deep, narrow Ligurian oceanic basin, and (ii) the large number of structures inherited from the Alpine orogeny. Historical seismicity reveals about twenty moderate-size earthquakes (up to M=6.0), mostly distributed along the Ligurian coast and the Vésubie valley. A recent geodetic experiment shows a significant strain rate during the last 50 years in the area between the Argentera massif and the Mediterranean coastline. Results of this experiment suggest a N-S shortening of about 2-4 mm/yr over the network, this shortening direction is consistent with the seismological (P-axes of earthquakes) and the microtectonic data. The Pennic front (E-NE of the Argentera massif) and the northern Ligurian margin are the most seismically active areas. In the Nice arc and in the Argentera massif, some seismic lineaments correspond to faults identified in the field (such as theTaggia-Saorge fault or the Monaco-Sospel fault). In the western part of the Alpes Maritimes, no seismic activity is recorded in the Castellane arc. In the field, geological evidence, such as offsets of recent alluvial sediments, recent fault breccia, speleothem deformations, radon anomalies and others indicates recent deformation along these faults. Nevertheless, to this date active fault scarps have not been identified: this probably results from a relatively high erosion rate versus deformation rate and from the lack of Quaternary markers. We also suspect the presence of two hidden active faults, one in the lower Var valley (Nice city area) and the other one at the base of the Argentera crustal thrust-sheet. Offshore, along the northern Ligurian margin, the seismic reflection data shows traces of Quaternary extensional deformation, but the accuracy of the data does not yet allow the construction of a structural map nor does it allow the determination of the continuity between the offshore and onshore structures. From these data set we propose a preliminary map of 11 active faults and we discuss the questions which remain unsolved in the perspective of seismic hazard evaluations.

Early Cretaceous syn- to post-rift evolution of the Mentelle Basin on the southwest Australian rifted margin (IODP Expedition 369 Sites U1513–U1516)

2021 ◽  
Author(s):  
Eun Young Lee ◽  
Erik Wolfgring ◽  
Maria Luisa G. Tejada ◽  
Seung Soo Chun ◽  
Sangheon Yi ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Middle Jurassic ◽  
Volcanic Rocks ◽  
Indian Plate ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Volcanic Sequence ◽  
International Ocean Discovery Program ◽  
Rifted Margin ◽  
Thermal Subsidence

&lt;p&gt;The Mentelle Basin is a large and deep-water sedimentary basin located on the southwest Australian rifted margin. The basin lies west of the Perth Basin, east of the Naturaliste Plateau and south of the Perth Abyssal Plain. The rifted margin formed when the Greater Indian plate separated from the Australian-Antarctic plate during the Jurassic to early Cretaceous. Based on seismic reflection data, several km thick sediments infilling the basin have been interpreted. However, due to lack of geological and geophysical data, the basin has not been studied enough to understand its evolution. In 2017, International Ocean Discovery Program (IODP) Expedition 369 drilled four sites, U1513&amp;#8211;U1516, in the Mentelle Basin and recovered important cores including late Jurassic to Early Cretaceous sections. At Site U1515 on the eastern margin of the basin, drilling penetrated below the seismically imaged breakup unconformity into the middle Jurassic to earliest Cretaceous syn-rift strata. Holes at Site U1513 on the western margin cored the syn-rift volcanic sequence, the Hauterivian to early Aptian volcaniclastic-rich sandstone sequence spanning the syn- to post-rift phase, and the Aptian to Albian post-rift claystone sequence. Drilling at Sites U1514 and U1516 in the central part reached the Albian post-rift sequence. Using a combination of shipboard and post-expedition data, we interpret the lithological, paleontological and geochemical characteristics of the syn- to post-rift sequences. The results allowed us to reconstruct the Early Cretaceous stratigraphy, tectonics, paleo-environment, and basin evolution of the Mentelle Basin. During the syn-rift phase, the middle Jurassic to lower Cretaceous non-marine sediments were deposited in the eastern Mentelle Basin, while volcanic rocks were emplaced in the western part. The 82 m thick volcanic sequence consists of alternating basalt flows and volcaniclastics with dolerite dikes, which indicate multiple volcanic eruption events in subaerial to shallow water environments. It was overlain by the 235 m thick volcaniclastic-rich sequence consisting of massive or laminated sandstone layers, deposited in shelf to upper bathyal depths. The deposition period spans the syn- to post-rift phase of the basin but decreasing sedimentation rate and shallow marine setting suggest that the post-rift thermal subsidence did not immediately follow the final continental breakup. We interpret that the delayed thermal subsidence was likely to be induced by adjacent mantle plume activities. Deep marine claystone sequences blanketing most of the basin indicate Aptian to Albian post-rift thermal subsidence.&lt;/p&gt;

Identifying seismically active blind thrusts by geomorphology and seismic reflection profiles in a reactivated back-arc failed rift basin, Northeast Japan

2020 ◽  
Author(s):  
Tatsuya Ishiyama ◽  
Hiroshi Sato ◽  
Naoko Kato ◽  
Susumu Abe ◽  
Satoru Yokoi ◽  
...  
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Data Depth ◽  
Alluvial Plain ◽  
The Sea Of Japan ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Blind Thrust ◽  
Structural Growth ◽  
Back Arc

&lt;p&gt;Back-arc failed rifts in many subduction zones are recognized as mechanically and thermally weak zones that possibly play important roles in strain accommodation at later post-rift stages within the overriding plates. In case of Miocene back-arc failed rift structures in the Sea of Japan in the Eurasian-Pacific subduction system, Quaternary activity of post-rift positive inversion of normal faults are predominant, part of which are blurred by fast subsidence in alluvial plains above densified lower crust associated with mafic intrusion into rift axis. To define such active fault-related structures in alluvial plain with subtle geomorphic signatures, we collected new high-resolution seismic reflection data across the alluvial plain (Shonai plain) in Northeast Japan, where an enigmatic 1894 earthquake event (M7.0) caused devastating damages on local communities. We deployed hundreds of portable offline seismic recorders covering whole seismic lines and provided seismic shots using Vibroseis trucks at all nearby receivers, to create high-resolution, depth-converted cross sections based on seismic reflection data. Depth-converted sections to 2-3 km depth clearly illuminate pairs of west-vergent, thrust-related folds that deformed Miocene to Pleistocene sedimentary and volcaniclastic rocks. Among them, we defined previously unrecognized, west-dipping blind thrust structures beneath coastal plains that deform Pleistocene and Holocene basin-fill units. Structures of these blind thrusts are consistent with distribution of earthquake-damaged houses and, at least partly, might activate during the 1894 seismic event. Interestingly, upward extension of synclinal axial surfaces are consistent with very subtle west-facing fold scarps that deform alluvial plain deposits illuminated by DEM, suggesting recent fault activities and related structural growth of thrust-related folds. These examples nicely demonstrate that combining subtle geomorphology of constrained by DEM and high resolution seismic reflection profiling is an effective tool to define recent structural growth and activity of otherwise inaccessible blind thrust structures and mitigating their elusive seismic hazards.&lt;/p&gt;

The Himalayan Foreland Basin from collision onset to the present: a sedimentary–petrology perspective

2019 ◽  
Vol 483 (1) ◽  
pp. 65-122 ◽  
Author(s):  
Eduardo Garzanti
Keyword(s):  
Ad Hoc ◽  
Foreland Basin ◽  
Late Eocene ◽  
Low Rank ◽  
Indian Plate ◽  
Full Account ◽  
Sedimentary Petrology ◽  
Himalayan Foreland Basin ◽  
Higher Rank ◽  
Major Factors

AbstractThis chapter summarizes the available stratigraphic, petrographical and mineralogical evidence from sediments and sedimentary rocks on the evolution of the Himalayan belt and its associated foreland basin. The use of compositional signatures of modern sediments to unravel provenance changes and palaeodrainage evolution through time is hampered by a poor match with detrital modes of ancient strata markedly affected by selective chemical dissolution of unstable minerals during diagenesis. Only semi-quantitative diagnoses can thus be attempted. Volcanic detritus derived from Transhimalayan arcs since India–Asia collision onset at c. 60 Ma was deposited onto the Indian lower plate throughout the Protohimalayan stage, with the exception of the Tansen region of Nepal that is characterized by quartz-arenites yielding orogen-derived zircon grains. During the Eohimalayan stage, begun in the late Eocene when most sedimentation ceased in the Tethys Himalayan domain, low-rank metasedimentary detritus was overwhelming in the central foreland basin, where a widespread unconformity developed spanning locally as much as 20 myr. Volcanic detritus from Transhimalayan arcs remained significant in northern Pakistan. Arrival of higher-rank metamorphic detritus since the earliest Miocene, and the successive occurrence of garnet, staurolite, kyanite and finally sillimanite, characterized the Neohimalayan stage, when repeated compositional changes in the foreland-basin succession document the stepwise propagation of crustal deformation across the Indian Plate margin and widening of the thrust belt with exhumation of progressively more external tectonic units. The correspondence in time between the activity of major thrusts and petrofacies changes indicates a promising approach to accurately reconstruct the geological evolution of the coupled orogen–basin system. Conversely, a poor conceptual framework and the general reliance on ad hoc mechanisms to explain phenomena unpredicted by simplified models represent major factors limiting the robustness of palaeotectonic interpretations. Improved knowledge requires taking into full account the dynamic role played by still poorly understood subduction processes – rather than exclusively the effect of passive loading – as well as the role played by the presence of inherited structures on the downgoing Indian Plate, which control both lateral variability of orogenic deformation and the location of depocentres in the foreland basin.

Deformation styles at the Appalachian structural front, western Newfoundland: implications of new industry seismic reflection data

1998 ◽  
Vol 35 (11) ◽  
pp. 1288-1306 ◽  
Author(s):  
Glen S Stockmal ◽  
Art Slingsby ◽  
John WF Waldron
Keyword(s):  
Seismic Reflection ◽  
Hydrocarbon Exploration ◽  
Canadian Cordillera ◽  
Seismic Reflection Data ◽  
Middle Ordovician ◽  
Reflection Data ◽  
Triangle Zone ◽  
Structural Style ◽  
Southeastern Margin ◽  
New Industry

New seismic reflection data gathered during hydrocarbon exploration in and adjacent to the external Humber zone, western Newfoundland, have important implications for the interpretation of structural style at the Appalachian front. These new data indicate that the structural front is influenced by both thin-skinned and thick-skinned structures. Where the structural front is thin skinned, it is characterized by a triangle zone, or tectonic wedge, similar to structures observed at the southeastern margin of the Canadian Cordillera, and at other orogenic fronts. The thin-skinned tectonic wedge is overridden locally by thick-skinned thrusts, which are generally emergent but are locally blind, forming a thick-skinned tectonic wedge. Timing relationships indicate that, although initial motion occurred during the Early to Middle Ordovician Taconian orogeny, the thin-skinned allochthonous slices in western Newfoundland were not emplaced until Devonian time (the Acadian orogeny). Thick-skinned deformation, which postdates thin-skinned thrusting, probably occurred between Middle Devonian and earliest Carboniferous time.

scholarly journals Timor Collision Front Segmentation Reveals Potential for Great Earthquakes in the Western Outer Banda Arc, Eastern Indonesia

2021 ◽  
Vol 9 ◽  
Author(s):  
Aurélie Coudurier-Curveur ◽  
Satish C. Singh ◽  
Ian Deighton
Keyword(s):  
Active Faults ◽  
Accretionary Prism ◽  
Historical Seismicity ◽  
Normal Faults ◽  
Seismic Reflection Data ◽  
Spatially Correlated ◽  
Eastern Indonesia ◽  
The North ◽  
Reflection Data ◽  
Banda Arc

In Eastern Indonesia, the western Outer Banda arc accommodates a part of the oblique Australian margin collision with Eurasia along the Timor Trough. Yet, unlike the Wetar and Alor thrusts of the Inner Banda arc in the north and the adjacent Java subduction zone in the west, both recent and historical seismicity along the Timor Trough are extremely low. This long-term seismic quiescence questions whether the Banda Arc collision front along the Timor Trough is actually fully locked or simply aseismic and raises major concerns on the possible occurrence of large magnitude and tsunamigenic earthquakes in this vulnerable and densely populated region. Here, we jointly analyze multibeam bathymetry and 2D seismic reflection data acquired along the Timor Trough to characterize the location, nature, and geometry of active faults. Discontinuous narrow folds forming a young accretionary prism at the base of the Timor wedge and spatially correlated outcropping normal faults on the bending northwest Australian shelf reveal two concurrent contrasting styles of deformation: underthrusting and frontal accretion. We find that those tectonic regimes and their associated seismic behaviors depend on 1) the thickness of the incoming and underthrusting Cenozoic sedimentary sequence, 2) the vergence of inherited normal faults developed within the continental shelf, and 3) the depth of the décollement beneath the Timor wedge. Based on the along-strike, interchanging distinct deformation style, we identify the mechanical and seismic segmentation along the Banda arc collision front and discuss the implications for earthquake and tsunami hazards along the western Outer Banda arc region.

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