Cambrian and earliest Ordovician fauna and geology of the Sông Đà and adjacent terranes in Việt Nam (Vietnam)

2021 ◽  
pp. 1-26
Author(s):  
Nigel C. Hughes ◽  
Shanchi Peng ◽  
David A. T. Harper ◽  
Paul M. Myrow ◽  
Ngân Kim Phạm ◽  
...  
Keyword(s):  
South China ◽  
Detrital Zircon ◽  
North China ◽  
Tectonic Deformation ◽  
Viet Nam ◽  
Carbonate Facies ◽  
The South ◽  
The North ◽  
Lower Ordovician ◽  
A New Species

Abstract Later Cambrian and earliest Ordovician trilobites and brachiopods spanning eight horizons from five localities within the Sông Mã, Hàm Rồng and Đông Sơn formations of the Thanh Hóa province of Việt Nam, constrain the age and faunal affinities of rocks within the Sông Đà terrane, one of several suture/fault-bounded units situated between South China to the north and Indochina to the south. ‘Ghost-like’ preservation in dolomite coupled with tectonic deformation leaves many of the fossils poorly preserved, and poor exposure precludes collecting within continuously exposed stratigraphic successions. Cambrian carbonate facies pass conformably into Lower Ordovician carbonate-rich strata that also include minor siliciclastic facies, and the recovered fauna spans several uppermost Cambrian and Lower Ordovician biozones. The fauna is of equatorial Gondwanan affinity, and comparable to that from South China, North China, Sibumasu and Australia. A new species of Miaolingian ‘ptychopariid’ trilobite, Kaotaia xuanensis, is described. Detrital zircon samples from Cambrian–Ordovician rocks of the North Việt Nam and Sông Đà terranes, and from Palaeozoic samples from the Trường Sơn sector of Indochina immediately to the south, contain a predominance of ages spanning the Neoproterozoic period and have a typical equatorial Gondwanan signature. We associate the Cambrian and Tremadocian of the Sông Đà terrane with areas immediately to the north of it, including the North Việt Nam terrane and the southern parts of Yunnan and Guangxi provinces of China.

scholarly journals Proterozoic−Phanerozoic tectonic evolution of the Qilian Shan and Eastern Kunlun Range, northern Tibet

2021 ◽  
Author(s):  
Chen Wu ◽  
Jie Li ◽  
Andrew V. Zuza ◽  
Peter J. Haproff ◽  
Xuanhua Chen ◽  
...  
Keyword(s):  
South China ◽  
Tectonic Evolution ◽  
North China ◽  
The South ◽  
The North ◽  
South China Craton ◽  
Late Neoproterozoic ◽  
North And South ◽  
North Qilian ◽  
Early Neoproterozoic

The Proterozoic−Phanerozoic tectonic evolution of the Qilian Shan, Qaidam Basin, and Eastern Kunlun Range was key to the construction of the Asian continent, and understanding the paleogeography of these regions is critical to reconstructing the ancient oceanic domains of central Asia. This issue is particularly important regarding the paleogeography of the North China-Tarim continent and South China craton, which have experienced significant late Neoproterozoic rifting and Phanerozoic deformation. In this study, we integrated new and existing geologic field observations and geochronology across northern Tibet to examine the tectonic evolution of the Qilian-Qaidam-Kunlun continent and its relationships with the North China-Tarim continent to the north and South China craton to the south. Our results show that subduction and subsequent collision between the Tarim-North China, Qilian-Qaidam-Kunlun, and South China continents occurred in the early Neoproterozoic. Late Neoproterozoic rifting opened the North Qilian, South Qilian, and Paleo-Kunlun oceans. Opening of the South Qilian and Paleo-Kunlun oceans followed the trace of an early Neoproterozoic suture. The opening of the Paleo-Kunlun Ocean (ca. 600 Ma) occurred later than the opening of the North and South Qilian oceans (ca. 740−730 Ma). Closure of the North Qilian and South Qilian oceans occurred in the Early Silurian (ca. 440 Ma), whereas the final consumption of the Paleo-Kunlun Ocean occurred in the Devonian (ca. 360 Ma). Northward subduction of the Neo-Kunlun oceanic lithosphere initiated at ca. 270 Ma, followed by slab rollback beginning at ca. 225 Ma evidenced in the South Qilian Shan and at ca. 194 Ma evidenced in the Eastern Kunlun Range. This tectonic evolution is supported by spatial trends in the timing of magmatism and paleo-crustal thickness across the Qilian-Qaidam-Kunlun continent. Lastly, we suggest that two Greater North China and South China continents, located along the southern margin of Laurasia, were separated in the early Neoproterozoic along the future Kunlun-Qinling-Dabie suture.

Research progress on the Zhongnan-Liyue Fault Zone in the South China Sea Basin

2020 ◽  
Author(s):  
Ziying Xu ◽  
Jun Wang ◽  
Hongfang Gao ◽  
Yongjian Yao
Keyword(s):  
Spatial Distribution ◽  
South China Sea ◽  
Fault Zone ◽  
South China ◽  
The South China Sea ◽  
Magnetic Data ◽  
Tectonic Deformation ◽  
The South ◽  
China Sea ◽  
The North

<p>We give a review of the up-to-date research situation about The Zhongnan-Liyue Fault Zone (ZLFZ), than analyze the spatial distribution and tectonic deformation feature of the ZLFZ based on the geophysical data including topographic, seismic, gravity and magnetic data. The results show that the ZLFZ has obvious north-south segmentation characteristics in in the South China Sea Basin. The north section, which is between northwest sub-basin and east sub-basin, is a narrow zone with the width of ~16 km, and is NNW trend from 18°N,115.5°E to 17.5°N,116°E. Meanwhile ,the south section, which is between southwest sub-basin and east sub-basin, is a wide zone with the width of 60-80 km, and is NNW trend from the east of ZhongshaBank to the west of LiyueBank. The main fault of the ZLFZ is NNW trend along the seamounts ridge of Zhongnan. the ZLFZ of transition region is NNE trend from the north section to the south section. According the sub-basin’s sedimentary thickness and oceanic crust thickness exist obvious difference, on both sides of the ZLFZ, we speculate that the ZLFZ play an important role on geological structure of sub-basin. According to the chang of crustal structure, We speculate that the ZLFZ is at least a crustal fracture zone.</p><p><strong>Key words: </strong>South China Sea Basin; Zhongnan-Liyue Fault Zone; Spatial distribution; Tectonic deformation<strong> </strong></p><p><strong>Foundation item:</strong> National Natural Science Foundation of China (41606080, 41576068); The China Geological Survey Program (GZH201400202, 1212011220117, DD20160138, 1212011220116).</p>

Timing of Paleozoic amalgamation between the North China and South China Blocks: Evidence from detrital zircon U–Pb ages

2013 ◽  
Vol 586 ◽  
pp. 173-191 ◽  
Author(s):  
Yunpeng Dong ◽  
Xiaoming Liu ◽  
Franz Neubauer ◽  
Guowei Zhang ◽  
Ni Tao ◽  
...  
Keyword(s):  
South China ◽  
Detrital Zircon ◽  
North China ◽  
The North

Mesozoic Hydrothermal Overprint on Carboniferous Bauxite in China

2020 ◽  
Author(s):  
Ruixue Wang ◽  
Qingfei Wang ◽  
I. Tonguç Uysal ◽  
Erick Ramanaidou ◽  
Jun Deng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Raman Spectra ◽  
South China ◽  
Intensity Ratio ◽  
North China ◽  
South China Block ◽  
The South ◽  
North China Block ◽  
The North ◽  
North And South

Abstract Bauxite is the world’s main source of aluminum and typically consists of gibbsite, boehmite, and minor amounts of diaspore. However, bauxite deposits from the North and South China blocks consist mostly of diaspore and associated minerals, including anatase and illite. Much of this illite is authigenic and occurs as three polytypes (1M, 1Md, and 2M1), with Kübler indices ranging from 0.23 to 0.47 indicating precipitation temperatures of 175° to 300°C. The Raman spectra of anatase show an intensity ratio of <1.5 for G (~1,600 cm–1) and D bands (~1,350 cm–1) diagnostic of organic matter, suggesting its presence during bauxite sedimentation followed by heating (165° to 270°C). The K-Ar ages of authigenic illite from the South China block (178–137 Ma) and the North China block (214–203 Ma) are synchronous with known regional Mesozoic tectono-thermal events generating hydrothermal overprints resulting in (1) the formation of illite, (2) the conversion of some diaspores from thermal of gibbsite and boehmite, and (3) the heating of anatase postsedimentation of the Carboniferous bauxites.

scholarly journals New insights on the early Mesozoic evolution of multiple tectonic regimes in the northeastern North China Craton from the detrital zircon provenance of sedimentary strata

2018 ◽  
Author(s):  
Yi Ni Wang ◽  
Wen Liang Xu ◽  
Feng Wang ◽  
Xiao Bo Li
Keyword(s):  
Detrital Zircon ◽  
North China Craton ◽  
North China ◽  
Early Jurassic ◽  
Orogenic Belt ◽  
Late Triassic ◽  
Early Triassic ◽  
The South ◽  
The North ◽  
Early Mesozoic

Abstract. To investigate the timing of deposition and provenance of early Mesozoic strata in the northeastern North China Craton (NCC), and to reconstruct the early Mesozoic tectono-paleogeography of the region, we combine LA–ICP–MS detrital zircon U–Pb dating, Hf isotopic data. Early Mesozoic strata include the Early Triassic Heisonggou, Late Triassic Changbai and Xiaoyingzi, and Early Jurassic Yihe formations. Detrital zircons in the Heisonggou Formation comprise ~ 58 % Neoarchean to Paleoproterozoic and ~ 42 % Phanerozoic grains that were sourced from areas to the south and north of the basins within the NCC. This indicates that Early Triassic deposition was controlled primarily by southward subduction of the Paleo-Asian oceanic plate beneath the NCC, and collision between the NCC and the Yangtze Craton (YC). Approximately 88 % of sediments within the Late Triassic Xiaoyingzi Formation were sourced from the NCC to the south, with the remaining ~ 12 % from the Xing'an–Mongol Orogenic Belt (XMOB) to the north. This implies that Late Triassic deposition was related to the final closure of the Paleo-Asian Ocean during the Middle Triassic and the rapid exhumation of the Su–Lu Orogenic Belt between the NCC and YC. In contrast, ~ 88 % of sediments within the Early Jurassic Yihe Formation were sourced from the XMOB to the north, with the remaining ~ 12 % from the NCC to the south. We therefore infer that rapid uplift of the XMOB and the onset of subduction of the Paleo-Pacific Plate beneath Eurasia occurred in the Early Jurassic.

scholarly journals Late Triassic successive amalgamation between the South China and North China blocks: Insights from structural analysis and magnetic fabrics study of the Bikou Terrane and its adjacent area, northwestern Yangtze block, central China

2021 ◽  
Author(s):  
Zhenhua Xue ◽  
Wei Lin ◽  
Yang Chu ◽  
Wei Wei ◽  
Zhentian Feng ◽  
...  
Keyword(s):  
Structural Analysis ◽  
South China ◽  
North China ◽  
Late Triassic ◽  
Yangtze Block ◽  
The South ◽  
Structural Geometry ◽  
The North ◽  
Magnetic Fabrics ◽  
Multi Phase

The Bikou Terrane, located at the conjunction of the Longmenshan fold-thrust belt and the west Qinling orogenic belt in centeral China, was involved in the Late Triassic collision between the South China and North China blocks. The Bikou Terrane has preserved crucial information on structural geometry and kinematics of Triassic tectonics, and is therefore of great importance for reconstructing the Paleo-Tethyan evolutionary history. However, multi-phase tectonic events of the Bikou Terrane are unsettled. This work presents detailed structural analysis based on both the field and laboratory works, which reveals three phases of deformation events in Bikou and its adjacent areas, including top-to-the-SW shearing related to SW-ward thrusting (DI) mainly to the north of the Bikou Terrane, top-to-the-NNW shearing related to NNW-ward thrusting (DII) in the Bikou Terrane, and strike-slip faulting (DIII) locally developed in the northern Bikou Terrane. Anisotropy of magnetic susceptibility (AMS) study and related structural analysis not only support the multiphase deformation but also reveal a gradual transition from the DII-related magnetic fabrics to the DIII-related magnetic fabrics in the Bikou Terrane. Integrating published geochronological data, it is constrained that DI occurred at ca. 237−225 Ma, DII occurred at ca. 224−219 Ma, and DIII possibly occurred during the Early Cretaceous. Based on regional tectonics, the DI event corresponds to the collision between the South Qinling block and the Bikou Terrane, and the DII event reflects the intracontinental amalgamation between the Bikou Terrane and the Yangtze block, which indicates a Late Triassic successive amalgamation from the North China block to the South China block. Intracontinental adjustment represented by the strike-slip (DIII event) occurred after the final amalgamation between the North China and South China blocks. By applying AMS on deciphering structural geometry and multi-phase deformation, our study suggests that AMS is a useful tool for structural analysis.

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