Lithospheric structure and dynamic processes of the Tianshan orogenic belt and the Junggar basin

Zhao, Junmeng; Liu, Guodong; Lu, Zhaohui; Zhang, Xian‐Kang; Zhao, Guosong

doi:10.1016/j.tecto.2003.07.001

Cited by 133 publications

(41 citation statements)

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“…It therefore proves that the emplacement of a dense granulite residue under the Chinese Altai can provide the observed high gravity signal. The Tectonics 10.1002/2016TC004271 presence of a dense lower crust under the Chinese Altai was previously determined from a density model inferred from seismic data [Zhao et al, 2003], and it was thought to be caused by mafic-ultramafic cumulates crystallized from the ascending arc magma. However, the density values used in their model for the lower crust of the Chinese Altai range from 2970 to 2990kg/m 3 , significantly higher compared to our model.…”

Section: Residual Gravity High Over the Chinese Altai: A Consequence mentioning

confidence: 99%

“…The question of whether the gravity anomalies across the Altai Orogenic Belt can be linked with the metamorphic evolution is further investigated by conducting a forward gravity modeling of the Complete Bouguer anomalies along a selected profile (Figure 10c). In the absence of any seismic profile across the Chinese Altai and MA-HVD regions, the modeling of the crust-mantle boundary is constrained by the CRUST 1.0 model [Laske et al, 2013] combined with the seismic profiles of Zhao et al [2003] and Wang et al [2003] for the Junggar Basin. In addition, the gravity modeling is constrained by surface geological Tectonics 10.1002/2016TC004271 observations and the boundaries of the major lithological units.…”

Section: Residual Gravity High Over the Chinese Altai: A Consequence mentioning

confidence: 99%

“…In addition, the gravity modeling is constrained by surface geological Tectonics 10.1002/2016TC004271 observations and the boundaries of the major lithological units. In this profile, the crustal architecture of the Junggar portion was constrained by available geological and seismic data of Zhao et al [2003] and Bian et al [2010]. The Chinese Altai architecture featured by doming of dense lower crustal rocks was inferred from Jiang et al [2015], and the MA-HVD structure was characterized by Mongolian Altai Ordovician metasediments thrust over the Early Cambrian gabbroic rocks of the Lake Zone based on the study of Lehmann et al [2010].…”

Section: Residual Gravity High Over the Chinese Altai: A Consequence mentioning

confidence: 99%

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Anatexis of accretionary wedge, Pacific-type magmatism, and formation of vertically stratified continental crust in the Altai Orogenic Belt

et al. 2016

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Granitoid magmatism and its role in differentiation and stabilization of the Paleozoic accretionary wedge in the Chinese Altai are evaluated in this study. Voluminous Silurian‐Devonian granitoids intruded a greywacke‐dominated Ordovician sedimentary succession (the Habahe Group) of the accretionary wedge. The close temporal and spatial relationship between the regional anatexis and the formation of granitoids, as well as their geochemical similarities including rather unevolved Nd isotopic signatures and the strong enrichment of large‐ion lithophile elements relative to many of the high field strength elements, may indicate that the granitoids are product of partial melting of the accretionary wedge rocks. Whole‐rock geochemistry and pseudosection modeling show that regional anatexis of fertile sediments could have produced a large amount of melts compositionally similar to the granitoids. Such process could have left a high‐density garnet‐ and/or garnet‐pyroxene granulite residue in the deep crust, which can be the major reason for the gravity high over the Chinese Altai. Our results show that melting and crustal differentiation can transform accretionary wedge sediments into vertically stratified and stable continental crust. This may be a key mechanism contributing to the peripheral continental growth worldwide.

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Section: Residual Gravity High Over the Chinese Altai: A Consequence mentioning

confidence: 99%

Section: Residual Gravity High Over the Chinese Altai: A Consequence mentioning

confidence: 99%

Section: Residual Gravity High Over the Chinese Altai: A Consequence mentioning

confidence: 99%

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Anatexis of accretionary wedge, Pacific-type magmatism, and formation of vertically stratified continental crust in the Altai Orogenic Belt

et al. 2016

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“…To the north, the North Tianshan Fault (NTF; Zhao et al, 2003) along the north boundary of the Yili Block extends eastward merging into the Main Tianshan Shear Zone (MTSZ; Laurent-Charvet et al, 2002, Laurent-Charvet et al, 2003 along the northern margin of the Central Tianshan. To the south, the Nalati Fault (NF)-Baluntai Fault-Xingxingxia Fault (Wang et al, 2014;Zhao et al, 2003) extend along the southern margins of the Yili and Central Tianshan blocks (Figure 1b). Displacements along these faults are considered as reactivations of the older suture zones during the Permian to Triassic and predominantly show dextral kinematics (de Jong et al, 2009;Laurent-Charvet et al, 2003;Wang et al, 2006;Wang et al, 2009;Yin & Nie, 1996).…”

Section: Geological Background and Paleomagnetic Samplingmentioning

confidence: 99%

Constraining the Intracontinental Tectonics of the SW Central Asian Orogenic Belt by the Early Permian Paleomagnetic Pole for the Turfan‐Hami Block

et al. 2019

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In order to better understand the kinematics and geodynamics of the late Paleozoic to early Mesozoic transition from accretionary to intracontinental tectonics in the southwest Central Asian Orogenic Belt, we performed a paleomagnetic study on Lower Permian strata in the Turpan‐Hami Basin, NW China. Magnetite and hematite are shown to be the principal magnetic remanence carriers. A typical sedimentary fabric that has not been modified by postdepositional deformation is recognized via magnetic fabric study. Stable characteristic remanent magnetizations, all of reverse magnetic polarity, are revealed by step demagnetizations. Remanence age is determined to be of Early Permian affinity, based on a fold test, remanence behavior of minerals, and geochronologic data. With inclination shallowing corrections, the first Early Permian paleomagnetic pole for the Turpan‐Hami Block is acquired as λ = 75.7°N, φ = 276.3°E, A95 = 5.7°, and N = 10 sites. Comparisons of this new pole with published ones from neighboring cratonic blocks provide kinematic constraints on the tectonic transition and subsequent intracontinental tectonics of this region. The Turpan‐Hami and Yili blocks have kept their relative positions since the Early Permian. Significant latitudinal movement of 14.7° ± 7.2° occurred between the Turpan‐Hami and South Junggar blocks and could be mainly accommodated by late Paleozoic crustal shortening of at least ~530 km across an intra‐arc basin in the Bogda belt. The Turpan‐Hami Block has experienced large‐magnitude relative rotations of −41.1° ± 7.1° and 21.2° ± 9.4° with respect to Tarim and South Junggar since the Early Permian, respectively, corresponding to dominant intracontinental tectonics characterized by large‐magnitude strike‐slip displacements along megashear zones.

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“…Besides, it seems that the Junggar lithosphere does not underthrust to the central Tian Shan, rather inserts laterally to the upper mantle of lithosphere of the Tian Shan. Seismic sounding and MT surveys also indicate the lateral insertion of the crust of the Junggar basin into the Tian Shan [10] . It is inferred from the transection B-B that such a lateral insertion happens within the crust and upper mantle lithosphere of the Tian Shan.…”

Section: Lithosphere Detachmentmentioning

confidence: 97%

Deep Features of Continental Collision Belts in North‐Western China and their Dynamic Significance

Xu¹,

Liu²,

Liu³

et al. 2001

Chinese J of Geophysics

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[Abstract] Several possible collision types of the western orogenic belts with adjacent blocks are suggested through analyzing the deep configuration of the lithosphere and asthenosphere of continental blocks, based on the results of seismic tomography in northwestern China. Tectonic patterns such as the embedding, underthrusting, detaching and sinking of lithospheric blocks occur between the Tian Shan mountain and the Tarim basin. Moreover, sharp boundaries exist between the Qinghai-Xizang Plateau and its northern geological untis, as evidence of the upper mantle extending to the north. It is inferred that the QinghaiXizang lithosphere probably has been blocked by the thick Tarim lithosphere and bent or broken near the boundary during the process of its northward motion. Nevertheless, the shallower asthenosphere north of the Qilian moiuntain behaves as a free boundary, so as makes the upper mantle of the Qinghai-Xizang Plateau extend to the north much easier. The collision between continental blocks not only changes the lithospheric structure of the orogenic belt in northwestern China, but also results in the upwelling of the partially melted material from asthenosphere, which intrudes the base of the lithosphere beneath the orogenic belt along the collision boundary. To some degree, they have played important roles in the elevation of the Qinghai-Xizang Plateau and western orogenic belts.

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Lithospheric structure and dynamic processes of the Tianshan orogenic belt and the Junggar basin

Cited by 133 publications

References 2 publications

Anatexis of accretionary wedge, Pacific-type magmatism, and formation of vertically stratified continental crust in the Altai Orogenic Belt

Anatexis of accretionary wedge, Pacific-type magmatism, and formation of vertically stratified continental crust in the Altai Orogenic Belt

Constraining the Intracontinental Tectonics of the SW Central Asian Orogenic Belt by the Early Permian Paleomagnetic Pole for the Turfan‐Hami Block

Deep Features of Continental Collision Belts in North‐Western China and their Dynamic Significance

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