Metamorphic evolution and age constraints of the garnet-bearing mica schist from the Xindaduo area of the Sumdo (U)HP metamorphic belt, Tibet

2018 ◽  
Vol 156 (07) ◽  
pp. 1175-1189 ◽  
Author(s):  
CONG ZHANG ◽  
THOMAS BADER ◽  
LINGMIN ZHANG ◽  
TINGTING SHEN ◽  
PENG LI ◽  
...  
Keyword(s):  
Mica Schist ◽  
Metamorphic Belt ◽  
Metamorphic Evolution ◽  
Origin And Evolution ◽  
Lhasa Terrane ◽  
The North ◽  
Close Relationship ◽  
The Matrix ◽  
Tethys Ocean ◽  
North And South

AbstractAs one of the major components of the Himalayan–Tibetan Orogeny, the Lhasa terrane plays a key role in understanding the origin and evolution of this giant orogenic belt and the opening and closure of the Tethys oceans. The eclogite-bearing Sumdo Complex in the central Lhasa terrane was recognized as the main suture of the Palaeo-Tethys Ocean between the north and south Lhasa sub-terranes. Despite the eclogite having been studied for a long time, no attempts have been applied to studying the country rocks, causing confusion in understanding the relationship between the eclogite and the adjacent schist. Petrological investigations and phase equilibrium calculations on the garnet-bearing mica schist of the Sumdo Complex have been performed to constrain its metamorphic evolution. The P–T conditions for three metamorphic stages are constrained as P1 (480–500°C, 2.6–2.7 GPa), P2 (580–600°C, 1.3–1.4 GPa) and R (530°C, 0.9 GPa), which represent the prograde, temperature peak and retrograde stages. Two possible P–T paths were constructed, which experienced isothermal decompression (PT1) or heating with a decompression process (PT2), corresponding to the growth and extinction of garnet porphyroblasts in the matrix. The LA-MC-ICP-MS U–Pb dating method yielded a metamorphic age of 229.7±3.5 Ma, which was interpreted as the age of amphibolite-facies metamorphism at c. 600°C, 1.2–1.4 GPa during the closure of the Palaeo-Tethys Ocean, resulting in the aggregation of the north and south Lhasa sub-terranes. The close relationship between the eclogite and garnet-bearing mica schist, and their similar P–T–t paths indicate an in situ tectonic evolution rather than tectonic juxtaposition during exhumation.

Late Triassic orogenic assembly of the Tibetan Plateau: constraints from magmatism and metamorphism in the east Lhasa terrane

2021 ◽  
Author(s):  
Yanfei Chen ◽  
Zeming Zhang ◽  
Richard M Palin ◽  
Zuolin Tian ◽  
Hua Xiang ◽  
...  
Keyword(s):  
Crustal Thickening ◽  
Late Triassic ◽  
The Tibetan Plateau ◽  
Plate Convergence ◽  
Lhasa Terrane ◽  
The North ◽  
Tectonic History ◽  
Peak Metamorphism ◽  
Tethys Ocean ◽  
Lower Crustal

Abstract The early Mesozoic evolution of the Lhasa terrane, which represents a major component of the Himalayan-Tibetan orogen, remains highly controversial. In particular, geological units and events documented either side of the eastern Himalayan syntaxis (EHS) are poorly correlated. Here, we report new petrological, geochemical and geochronological data for co-genetic peraluminous S-type granites and metamorphic rocks (gneiss and schist) from the Motuo–Bomi–Chayu region of the eastern Lhasa terrane, located on the eastern flank of the EHS. Zircon U–Pb dating indicates that these units record both Late Triassic magmatic (216–206 Ma) and metamorphic (209–198 Ma) episodes. The granites were derived from a Paleoproterozoic crustal source with negative zircon εHf(t) values (–5.5 to –16.6) and TDM2 model ages of 1.51–1.99 Ga, and are interpreted to have formed by crustal anatexis of nearby metasediments during collisional orogeny and crustal thickening. The gneisses and schists experienced similar upper amphibolite-facies peak metamorphism and associated partial melting, followed by decompressional cooling and retrograde metamorphism. These rocks were buried to lower-crustal depths and then exhumated to the surface in a collisional orogenic setting during plate convergence. From comparison of these data to other metamorphic belts with similar grades and ages, and association of coeval granitic magmatism widespread in the central-east Lhasa terrane, we propose that the studied co-genetic magmatism and metamorphism in the Motuo–Bomi–Chayu region records Late Triassic accretion of the North Lhasa and South Lhasa terranes, which represents the first evidence of the Paleo-Tethys ocean (PTO) closure in this part of Asia. These data provide new constraints on the spatial and temporal evolution of the Paleo-Tethyan Wilson Cycle and provide a ‘missing link’ to correlate the geology and tectonic history of the Lhasa terrane continental crust on either side of the EHS.

scholarly journals Study on haplotype diversity of Y-STR loci of the Kinh population in Vietnam

2017 ◽  
Vol 33 (2S) ◽  
Author(s):  
Trinh Tuan Toan ◽  
Vu Le Loi ◽  
Ha Quoc Khanh ◽  
Nguyen Quang Vinh ◽  
Nguyen Quang Huy
Keyword(s):  
Haplotype Diversity ◽  
Genetic Distances ◽  
Statistical Validation ◽  
Finger Nail ◽  
Str Loci ◽  
The North ◽  
Migration History ◽  
Close Relationship ◽  
Forensic Case ◽  
North And South

The study was carried out to determine allele frequencies of Y-STRloci in order to apply in the statistical validation of forensic case and paternal lineages. 17 Y-STR loci were co-amplified (including: DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, and GATAH4) using DNA genome extracted from blood, hair root and finger nail samples of 205 unrelated men of Kinh population in the North and South of Vietnam. The studied population shows that a relatively close relationship between the Jiangxi (Han) and Jiangsu (Han) populations in China and the Han population in Taiwan. Compared to other population with geographic locations far removed from Vietnam and historically and culturally diverse, there are significant differences as with Americans (Rst = 0.3836, P <0.0001); The Germans (Rst = 0.3562, p = -1.0000); The Romans (Rst = 0.2918, p = -1.0000) or Ethiopian (Rst = 0.3139, p = -1.0000) and particularly significant differences with Nigerians (Rst = 0.5084, p = -1.0000). The genetic diversity indexes at each locus and the haplotypes were examined; Genetic distances between the King population in this study and neighboring populations and geographically remote populations are consistent with the migration history.  

scholarly journals On the origin and evolution of a new anchialine stygobitic <i>Microceratina</i> species (Crustacea, Ostracoda) from Christmas Island (Indian Ocean)

2004 ◽  
Vol 23 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Tadeusz Namiotko ◽  
Karel Wouters ◽  
Dan L. Danielopol ◽  
William F. Humphreys
Keyword(s):  
Sedimentary Facies ◽  
Marine Species ◽  
New Taxon ◽  
Fossil Species ◽  
Origin And Evolution ◽  
The North ◽  
Christmas Island ◽  
The Pacific ◽  
Tethys Ocean ◽  
The Baltic

Abstract. Marine species of the ostracod genus Microceratina Swanson (Cytheruridae, Eucytherurinae) were until now known only from their hard parts, the valves and carapaces, as no living animals have been described. Here we report the first living population, from a tropical anchialine cave. The description of the limbs and hard parts of this new taxon, M. martensi sp. nov., enhances our understanding of the origin and evolution of the cave-dwelling Microceratina – the new species and M. pseudoamfibola (Barbeito-Gonzalez) from an anchialine cave in Southern Italy – and clarifies their affinities with other Eucytherurinae species. Microceratina is known from both Recent and fossil species (Quaternary, Tertiary and Late Cretaceous) from shelf and deep-sea habitats and/or sedimentary facies, located in the Pacific Ocean (along the Australian and New Zealand coasts), the Mediterranean (Greece and Italy), the North Atlantic (British Isles) and the Baltic Sea (Rügen Island). This suggests that the Microceratina group spread through the expanding Tethys Ocean. The morphological traits of the two cave-dwelling species reflect their ecological conditions. Cave-dwelling Microceratina species appear to have originated from epigean shallow water species predisposed to colonize subterranean habitats.

Discovery of a Sphaeroschwagerina fusuline fauna from the Raggyorcaka Lake area, northern Tibet: implications for the origin of the Qiangtang Metamorphic Belt

2015 ◽  
Vol 153 (3) ◽  
pp. 537-543 ◽  
Author(s):  
YI-CHUN ZHANG ◽  
SHU-ZHONG SHEN ◽  
QING-GUO ZHAI ◽  
YU-JIE ZHANG ◽  
DONG-XUN YUAN
Keyword(s):  
Lake Area ◽  
Early Permian ◽  
Metamorphic Belt ◽  
Northern Tibet ◽  
The North ◽  
North And South

AbstractThe Qiangtang Metamorphic Belt (QMB) was considered to have either formed in situ by amalgmation of the North and South Qiangtang blocks or been underthrust from the Jinsha suture and exhumed in the interior of a single ‘Qiangtang Block’. A new Sphaeroschwagerina fusuline fauna discovered in the Raggyorcaka Lake area supports the interpretation that the North and South Qiangtang blocks were separated by a wide ocean during Asselian (Early Permian) time, indicating that the QMB was formed by the suturing of the Palaeotethys Ocean along the Longmu Co-Shuanghu suture.

Southward subduction of the Bangong-Nujiang Tethys Ocean: insights from ca. 161–129 Ma arc volcanic rocks in the north of Lhasa terrane, Tibet

2020 ◽  
Vol 109 (2) ◽  
pp. 631-647 ◽  
Author(s):  
Yue Tang ◽  
Qing-Guo Zhai ◽  
Pei-Yuan Hu ◽  
Sun-Lin Chung ◽  
Xu-Chang Xiao ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Lhasa Terrane ◽  
The North ◽  
Tethys Ocean

scholarly journals An Oligocene giant rhino provides insights into Paraceratherium evolution

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Tao Deng ◽  
Xiaokang Lu ◽  
Shiqi Wang ◽  
Lawrence J. Flynn ◽  
Danhui Sun ◽  
...  
Keyword(s):  
New Species ◽  
Tibetan Plateau ◽  
Eastern Coast ◽  
The Tibetan Plateau ◽  
Late Oligocene ◽  
Origin And Evolution ◽  
The North ◽  
North Side ◽  
Tethys Ocean ◽  
A New Species

AbstractAs one of the largest land mammals, the origin and evolution of the giant rhino Paraceratherium bugtiense in Pakistan have been unclear. We report a new species Paraceratherium linxiaense sp. nov. from northwestern China with an age of 26.5 Ma. Morphology and phylogeny reveal that P. linxiaense is the highly derived species of the genus Paraceratherium, and its clade with P. lepidum has a tight relationship to P. bugtiense. Based on the paleogeographical literature, P. bugtiense represents a range expansion of Paraceratherium from Central Asia via the Tibetan region. By the late Oligocene, P. lepidum and P. linxiaense were found in the north side of the Tibetan Plateau. The Tibetan region likely hosted some areas with low elevation, possibly under 2000 m during Oligocene, and the lineage of giant rhinos could have dispersed freely along the eastern coast of the Tethys Ocean and perhaps through some lowlands of this region.

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