Crustal Thickening of the South Qiangtang Terrane, Tibetan Plateau: Constraint from Late Cretaceous High-Sr/Y Granitic Rocks

2019 ◽  
Vol 127 (4) ◽  
pp. 457-473 ◽  
Author(s):  
Pei-Yuan Hu ◽  
Qing-Guo Zhai ◽  
Jun Wang ◽  
Yue Tang ◽  
Hai-Tao Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Late Cretaceous ◽  
Crustal Thickening ◽  
Granitic Rocks ◽  
The South ◽  
Qiangtang Terrane

Crustal thickening and uplift of the Qiangtang Terrane, Tibetan Plateau during the Late Cretaceous to Early Palaeocene: geochronology and geochemistry of the Saiduopugangri granite

2020 ◽  
Author(s):  
xue li ◽  
Guo-Sheng Sun ◽  
Gen-Yi Liu ◽  
Huan Zhou ◽  
Zi-Ling Shan ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Late Cretaceous ◽  
Crustal Thickening ◽  
Magma Source ◽  
Geodynamic Setting ◽  
The Tibetan Plateau ◽  
Weighted Mean ◽  
Lower Crustal ◽  
Qiangtang Terrane ◽  
Shoshonitic Series

There continues to be debate regarding the timing of the collision between the Indian and Eurasian plates and the uplift of the Tibetan Plateau. This study presents zircon U–Pb geochronology, whole-rock geochemistry, and Lu–Hf isotopic data for the Saiduopugangri granite of the Qiangtang Terrane, located within the core of the Tibetan Plateau. These data provide the basis for the geodynamic setting, petrogenesis, and characteristics of its magma source. Zircons from the Saiduopugangri granite yield a weighted-mean 206Pb/238U age of 62.72 ± 0.06 Ma, indicating that these rocks formed during the early Palaeocene. The rocks are members of the highly calc-alkaline to shoshonitic series, with weak peraluminous characteristics. Trace elements are characterised by high Sr (483–616ppm), and low Y (6–10ppm) and Yb (1ppm) content, typical of a high Sr and low Yb granite. The εHf(t) of zircon range from −2.14 to 2.35, with two-stage Hf model ages (TDM2) ranging from 1182 to 895Ma. These data suggest that the Saiduopugangri granite magma was derived from the melting of lower-crustal clastic meta-sedimentary rocks and mantle-derived basalts. The high Sr and low Yb granite characteristics and experimental results indicate that melting occurred at >1.2 GPa and >750 °C, consistent with a crustal thickness greater than 50km. Magmatism occurred from the Late Cretaceous to the early Palaeogene and is broadly synchronous with the collision timing between the Indian and Eurasian plates. The Saiduopugangri granite provides evidence of crustal thickening of the Tibetan Plateau and its age and petrogenesis constrain the timing of the initial uplift.

The Cretaceous crustal shortening and thickening of the South Qiangtang Terrane and implications for proto-Tibetan Plateau formation

2020 ◽  
Vol 78 ◽  
pp. 141-155 ◽  
Author(s):  
Z.B. Zhao ◽  
P.D. Bons ◽  
C. Li ◽  
G.H. Wang ◽  
X.X. Ma ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The South ◽  
Crustal Shortening ◽  
Qiangtang Terrane

Palaeomagnetic constraints on Himalayan-Tibetan tectonic evolution

1988 ◽  
Vol 326 (1589) ◽  
pp. 177-188 ◽  
Keyword(s):  
Tibetan Plateau ◽  
South China ◽  
Large Scale ◽  
Indian Subcontinent ◽  
Eastern China ◽  
Crustal Thickening ◽  
The Tibetan Plateau ◽  
South China Block ◽  
The South ◽  
Palaeomagnetic Data

Palaeomagnetic data from the Lhasa, Qiangtang and Kunlun Terranes of the Tibetan Plateau are used with data from stable Eurasia, eastern China and Indochina, to test different models of crustal thickening in the Tibetan Plateau, to attempt a Carboniferous palaeogeographic reconstruction, and to calculate the relative motion between the South China Block and the Indochina Block. The data suggest that since the onset of the India—Eurasia collision, the Lhasa Terrane has moved 2000 + 800 km north with respect to stable Eurasia. This indicates that strong internal defomation must have taken place in southern Eurasia since the collision, and thus challenges the model of large-scale underthrusting of the Indian subcontinent beneath the Tibetan Plateau as the mechanism for crustal thickening in Tibet. Palaeomagnetic results from the Kunlun Terrane show that it was at 22° south latitude during the Carboniferous. A Carboniferous reconstruction is presented in which the Kunlun and Qiangtang Terranes, several Indochina terranes, and the North and South China Blocks are grouped together. These units of continental crust all share the specific tropical and subtropical Cathaysian flora, and the group is therefore called the Cathaysian composite continent. To test the model of propagating extrusion tectonics, we have used newly available palaeomagnetic results from South China and Indochina to calculate probable displacements. This exercise suggests a rotation of about 8° of Indochina with respect to the South China Block that is smaller than the predicted rotation of 40°, A large eastward translation of the South China Block relative to the Indochina Block of about 1500 km is consistent with the palaeomagnetic data.

The Lions Gate Member: A New Late Cretaceous Sedimentary Subdivision in the Vancouver Area of British Columbia

1975 ◽  
Vol 12 (3) ◽  
pp. 464-471 ◽  
Author(s):  
G. E. Rouse ◽  
W. H. Mathews ◽  
R. H. Blunden
Keyword(s):  
British Columbia ◽  
Late Cretaceous ◽  
Vancouver Island ◽  
Granitic Rocks ◽  
The South ◽  
Plutonic Belt ◽  
South Shore

Sediments bordering Burrard Inlet in Greater Vancouver are described as the Lions Gate Member of the Burrard Formation. This new member, comprising the lowest part of the previously defined Burrard Formation, rests nonconformably upon deeply weathered granitic rocks of the Coast Plutonic belt, and dips southwards into the Whatcom Basin. Four sedimentary units are recognizable, comprising a basal unit of conglomerate with minor sandstone lenticles; a sandstone–siltstone unit; a shale unit; and an upper coarse arkose. The upper contact with overlying sandstone and shales of Tertiary age occurs on the south shore of Burrard Inlet. Palynomorphs from both surface and borehole samples are of Late Cretaceous (Campanian) age, suggesting correlation of the Lions Gate Member with the Extension-Protection Formation of eastern Vancouver Island.

Sign in / Sign up

Export Citation Format

Share Document