Structural deformation and evolution of right-lateral strike-slip tectonics of the Liaohe western depression during the early Cenozoic (original) (raw)
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Frontiers in Earth Science
The complex deformation styles of large intraplate strike-slip fault systems in the multi-stage superimposed basin are hot topics worldwide. This article proposes structural models and evolution processes for such strike-slip fault systems in the Tarim Basin based on high-resolution 3D seismic data and deep wells. Our analyses reveal that strike-slip fault in the Tarim Basin formed with different structural styles in five tectonic layers from the Sinian to the Permian that accompanies the Sinian rift systems and uplift, the Lower–Middle Cambrian reversed faults and salt tectonics, the Ordovician fault-karst systems, the Silurian to the Carboniferous en-echelon transtensional faults, and the Permian volcanic structures. Influenced by the multi-tectonic layers and complex evolution history, the strike-slip faults performed as multi-layer flower structures and various fault types. The evolution history of paleo-uplifts also influenced the distribution characteristics of strike-slip fau...
Earth and Planetary Science Letters, 2004
Whether the oblique left-reverse Northern Altyn Tagh fault has large cumulative offset (N120 km) is one of the most controversial issues concerning the deformation mechanics for the northern Tibetan Plateau. In order to obtain material constraints on its total displacement, sedimentologic and bedrock provenance analysis of Oligocene-Pleistocene strata on the northern side of the fault was conducted. Lithofacies analysis and 970 paleocurrent measurements show that these strata were products of fluvial systems originating from south of the fault, making it possible to constrain the fault's slip history by establishing cross-fault sediment/source linkages. Identification of 5217 conglomerate clasts in the field indicates that major clast types are quartzite (30-50%), schist/gneiss (increasing upsection from 10% to 40-50%), and marble (decreasing upsection from 20-30% to b10%). Although granitic clasts can be observed throughout the entire section, they do not constitute a major clast type in any single bed. Amphibolite clasts first occur in the middle part of the Miocene strata, and reach up to 5% in the Pliocene and Pleistocene strata. Accordingly, sandstone heavy mineral analysis indicates: (1) dominance of metamorphic over igneous minerals, (2) absence of contact metamorphic minerals, (3) dominance of greenschist facies minerals lower in the section and coexistence of both greenschist and amphibolite facies minerals in the upper part of the section. These observations are consistent with unroofing of Precambrian basement immediately to the south of the studied Oligocene-Pleistocene section and argue against any left-lateral translation greater than 30 km along the Northern Altyn Tagh fault. Therefore, our results preclude the possibility of large (N30 km) strike-slip translation on the Northern Altyn Tagh fault and support the model that strain induced by Indian indentation has been partitioned into left-slip on the Altyn Tagh fault and reverse dip-slip on the Northern Altyn Tagh fault.
Geochronology of the initiation and displacement of the Altyn Strike-Slip Fault, western China
Journal of Asian Earth Sciences, 2007
40 Ar/ 39 Ar dating studies have been carried out along the Dangjin Pass transect across the Altyn Strike-Slip Fault (ASSF). The samples gave ages of 445.2-454.3 Ma in the Northern Belt, 164.3-178.4 Ma in the Mesozoic Shear Zone and 26.3-36.4 Ma in the Cenozoic Shear Zone. Using the piercing point of the Bashikaogong Fault and the Cangma-Heihe Fault an offset of 350-400 km along the ASSF has been estimated. The 40 Ar/ 39 Ar dating of the syntectonic-growth or syntectonic-resetting minerals from the samples within the ASSF belt, and offset estimations from different age piercing points suggest that the ASSF should be initiated in the Middle Jurassic (178.4-160 Ma). Combined with previously reported ages, our studies show that the ASSF is characterized by multi-phase re-activation during 85-100, 25-40 and 8-10 Ma following its initiation in the Middle Jurassic in the regional tectonic setting of convergence between the Indian and Eurasian continents.
Science in China Series D: Earth Sciences, 2001
The ENE-striking Altyn Tagh fault (ATF), extending along the northern edge of the Tibetan Plateau, is one of the major important strike-slip faults, and has been known as one of the key areas to debate the eastward extrusion and crustral shortening models of the Tibetan Plateau during and after India-Asia collision. This paper mainly presents new evidence of Late Cenozoic sedimentary process to reconstruct the slip history of the ATF during the Late Cenozoic. Field measurements and laboratory analyses of the sedimentary characteristics in the Late Cenozoic basins in the central Altyn Tagh fault suggest that Late Cenozoic sedimentary sequence should be divided into three units according to facies changes. The paleo-topography reconstruction shows that the sedimentation in these basins was tightly related with the fault, indicating that the ATF has experienced at least three stages of strike slipping in the Late Cenozoic. New geological data from the Late Cenozoic sedimentary basins and the formation of the present Suo'erkuli basin provide evidence for the displacement of the fault. The result shows that the 80-100 km left-lateral strike-slip displacement of the fault has been accumulated in the Late Cenozoic.
Tectonics, 1991
The structures of the Liupan Shah area are characterized by numerous active thrust and strike-slip faults that suggest thin-skinned deformation. The structural history of this area can be divided into three phases that probably overlap one another in time and are parts of a single protracted deformation. The oldest Cenozoic deformational phase occurred probably between late Pliocene and early Quaternary time and produced some of the folds and thrust faults in the Liupan Shan and Yueliang Shan. During this phase, deformation was the result of approximately N50oE shortening, and the amount of shortening seems to have been about 1-2 kin. The second phase of deformation was dominated by leftlateral strike-slip faulting (left slip) on the N60øW striking Haiyuan fault zone and shortening on north-south trending structures; shortening was associated with a transfer of the leftslip displacement on the Haiyuan fault zone to shortening in areas farther east. Shortening occurred by thrust faulting in the Liupan Shan and Xiaoquan Shan and by folding in the Madong Shan. During this phase the orientation of shortening changed to N60ow. The average amount of shortening on the northsouth trending folds in the Madong Shan is about 6.3-7.8 kin. Most of the shortening on the Liupan Shan and Xiaoguan Shan thrust faults also occurred during this phase and amounted to a minimum of 4.8-6.3 km and 6.6-7.6 km, respectively, also with an orientation of N60øW. During the third phase of deformation, about 1-1.5 km of late Pleistocene to Recent left slip occurred on the Xiaokou fault, which was transferred into oblique left-slip thrusting in the Liupan Shan. At this time, deformation in the Madong Shan and Xiaoguan Shan ceased or was reduced to a very slow rate. The present, active left-slip on the Haiyuan fault zone is accommodated by shortening in the Liupan Shan area. The total displacement along the Haiyuan fault is essentially the same as the total amount of shortening in the Liupan Shan area. The sequence and interaction of strike-slip and thrust faults in the Liupan Shan 1Department of Earth, Atmospheric and Planetary Sciences,
Journal of Geophysical Research, 2013
The Dzhungarian strike-slip fault of Central Asia is one of a series of long, NW-SE right-lateral strike-slip faults that are characteristic of the northern Tien Shan region and extends over 300 km from the high mountains into the Kazakh Platform. Our field-based and satellite observations reveal that the Dzhungarian fault can be characterized by three 100 km long sections based on variation in strike direction. Through morphological analysis of offset streams and alluvial fans, and through optically stimulated luminescence dating, we find that the Dzhungarian fault has a minimum average late Quaternary slip rate of 2.2 +/- 0.8 mm/yr and accommodates N-S shortening related to the India-Eurasia collision. This shortening may also be partly accommodated by counterclockwise rotation about a vertical axis. Evidence for a possible paleo-earthquake rupture indicates that earthquakes up to at least Mw 7 can be associated with just the partitioned component of reverse slip on segments of the central section of the fault up to 30 km long. An event rupturing longer sections of the Dzhungarian fault has the potential to generate greater magnitude earthquakes (Mw 8); however, long time periods (e.g., thousands of years) are expected in order to accumulate enough strain to generate such earthquakes.
Journal of Asian Earth Sciences, 2015
Structural architecture and tectonic evolution of the Fangzheng sedimentary basin (NE China), and implications for the Abstract * Corresponding author. Address: The ~100-km-long, NE-SW-trending Fangzheng sedimentary basin is one of a series of Cenozoic petroliferous depocenters along the Tan-Lu Fault Zone (TLFZ) in NE China. It is delimited by the NW and SE Boundary Faults and dissected by the basin-parallel Central Fault, all of which are part of the dextral TLFZ displaying releasing and restraining bends along-strike. The basinal strata and its pre-Cenozoic basement show well-developed transtensional and transpressional structures in these domains. The stratigraphy in the basin consists of >5000-m-thick, fine-to coarse-grained clastic rocks, and represents shallow to deep lacustrine, fan delta, beach bar, and fluvial-fluvial delta depositional settings. The Paleocene-Eocene rock units (~1500 m) rest along an unconformity on a Mesozoic granitic basement, and appear to have been accumulated in local depocenters in the hanging walls of the oblique-normal NW and SE Boundary Faults. The Oligocene Baoquanling Formation (~3200 m) overlies these Paleogene units along a regional unconformity, which indicates a period of uplift and non-deposition caused by basin-wide contraction in the latest Eocene. An abrupt increase in the stratigraphic thickness of the Baoquanling Formation, particularly its Middle Oligocene Second member with extensive and thick mudstone deposits, suggests the development of increased accommodation space in a lacustrine environment within the Fangzhen Basin. This event was coeval with the timing of rejuvenated intra-basinal rifting caused by transtensional deformation along the Central and SE Boundary Faults. Oblique rifting along and across the basin during the Oligocene was accompanied by mafic magmatism, which produced hypabyssal diabasic intrusions and sills crosscutting the basinal strata. The main mode of deformation in late Miocene and younger rock units was strike-slip faulting, which produced oblique-slip normal faults and en-echélon folds. The fault geometry, kinematics and the related stress regime along the dextral TLFZ have played a major role in the development of local depocenters, including their shape, size and depth, and significantly affected the formation of source rocks and structural traps in the petroliferous Fangzhen Basin.
Cenozoic evolution of the Tan-Lu Fault Zone (East China)-Constraints from seismic data
Gondwana Research, 2015
The Tan-Lu Fault Zone (TLFZ) is a continental-scale strike-slip fault zone in the East China that contains rich and significant information about the Mesozoic-Cenozoic evolution of eastern Asia. It experienced a long-term and complex superimposed deformation characterized by Mesozoic sinistral and Cenozoic dextral motions. The fault has a well-documented Mesozoic sinistral displacement history, but its Cenozoic history is poorly known. In this study, based on the observations of the interrelationships of fault kinematics, fault geometry and concom-itant sedimentation, the Cenozoic evolution of the TLFZ is constrained by abundant seismic data from oil fields. Numerous bends along the Cenozoic master fault sensitively record changes in the stress field during strike-slip motion. Taking into account the Cenozoic evolution of the Bohai Bay Basin (east China), the evolutionary history of these strike-slip bends is investigated, and the results indicate that dextral motion along the TLFZ began at about 40 Ma. Furthermore, the Cenozoic evolutionary history of the TLFZ is suggested to include an ex-tensional deformation (with a possible weak sinistral shear) from 65 to 40 Ma. From 40 to 0 Ma, dextral motion occurred due to a change in the subduction direction of the Pacific Plate relative to the Eurasian Plate causing the fault to experience dextral shear with a component of extensional deformation. Dextral motion was most intense from 40 to 25 Ma, and then the dextral direction may have suddenly changed from a nearly NE-SW trend to a nearly N-S trend at around 25 Ma. Dextral motion was relatively enhanced again after 12 Ma and was particularly strong after 5 Ma. Episodic and ephemeral thrusting deformation might have occurred during the Quaternary. The cumulative Cenozoic dextral displacement of the TLFZ is far smaller than its Mesozoic sinistral strike-slip displacement (may be no more than 21 km).
Tectonics, 2003
New structural studies and 40Ar/39Ar dating in northwest China provide information about late Paleozoic strike-slip motions subsequent to accretional events, which built eastern central Asia during the Paleozoic. Two principal areas were affected by these large transcurrent motions. First, in the Tianshan range, main east-west ductile shear zones are dextral and coeval with an eastward decreasing greenschist retrograde metamorphism. Associated
Journal of Asian Earth Sciences, 2005
The Paleoproterozoic Liaohe assemblage and associated Liaoji granitoids represent the youngest basement in the Eastern Block of the North China Craton. Various structural elements and metamorphic reaction relations indicate that the Liaohe assemblage has experienced three distinct deformational events (D 1 to D 3 ) and four episodes of metamorphism (M 1 to M 4 ). The earliest greenschist facies event (M 1 ) is recognized in undeformed or weakly deformed domains wrapped by the S 1 schistosity, suggesting that M 1 occurred before D 1 . The D 1 deformation produced small, mostly meter-scale, isoclinal and recumbent folds (F 1 ), an associated penetrative axial planar schistosity (S 1 ), a mineral stretching lineation (L 1 ) and regional-scale ductile shear zones. Concurrent with D 1 was M 2 metamorphism, which occurred before D 2 and produced low-to medium-pressure amphibolite facies assemblages. Regionally divergent motion senses reflected by the asymmetric F 1 folds and other sense-of-shear indicators, together with the radial distribution of the L 1 lineation surrounding the Liaoji granitoids, imply that D 1 represents an extensional event. The D 2 deformation produced open to tight F 2 folds of varying scales, S 2 axial crenulation cleavages and ENE-NE-striking thrust faults, involving broadly NW-SE compression. Following D 2 was M 3 metamorphism that led to the formation of sillimanite and cordierite in low-pressure type rocks and kyanite in medium-pressure rocks. The last deformational event (D 3 ) formed NW-WNW-trending folds (F 3 ), axial planar kink bands, spaced cleavages (S 3 ), and strike -slip and thrust faults, which deflect the earlier D 1 and D 2 structures. D 3 occurred at a shallow crustal level and was associated with, or followed by, a greenschist facies retrograde metamorphic event (M 4 ).