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Detrital zircon geochronology of Precambrian basement sequences in the Jiangnan orogen: Dating the assembly of the Yangtze and Cathaysia Blocks

Authors :
Wang, Xiao-Lei
Zhou, Jin-Cheng
Griffin, W.L.
Wang, Ru-Cheng
Qiu, Jian-Sheng
O’Reilly, S.Y.
Xu, Xisheng
Liu, Xiao-Ming
Zhang, Gui-Lin
Source :
Precambrian Research. Oct2007, Vol. 159 Issue 1/2, p117-131. 15p.
Publication Year :
2007

Abstract

Abstract: In the Jiangnan orogen, a clear angular unconformity between the Precambrian basement sequences and the overlying Neoproterozoic sedimentary strata (e.g. the Danzhou/Banxi Group, younger than ca. 800Ma) marks the collisional orogenesis (the Jinning orogeny) between the Yangtze and Cathaysia Blocks. In contrast to the upright, open folds in the Danzhou/Banxi Group, the basement sequences were deformed into high-angle tight linear and isoclinal overturned folds. It has been previously accepted that the basement sequences are of Mesoproterozoic age. However, LA-ICP–MS U–Pb dating of detrital zircons suggests that the maximum depositional age of the basement sedimentary rocks in the western part of the Jiangnan orogen (i.e. the Sibao/Lengjiaxi Group) is ca. 860Ma. This provides a lower limit for the assembly of the Yangtze and Cathaysia Blocks. Consequently, there may be no significant (ca. 200Ma) early Neoproterozoic sedimentary hiatus in South China. These data, combined with published dates on orogeny-related igneous rocks in the Jiangnan orogen, indicate that the Jinning orogeny took place at 860–800Ma, significantly younger than the typical Grenvillian orogeny at 1.3–1.0Ga. The Sibao/Lengjiaxi Group may have been deposited in a foreland basin. The Yangtze Block and the arc terrains that resulted from the early subduction along the Jiangnan orogen might be the two main source regions for the sedimentary rocks. [Copyright &y& Elsevier]

Details

Language :
English
ISSN :
03019268
Volume :
159
Issue :
1/2
Database :
Academic Search Index
Journal :
Precambrian Research
Publication Type :
Academic Journal
Accession number :
27001179
Full Text :
https://doi.org/10.1016/j.precamres.2007.06.005