成果归属作者：

张世红 ; 吴怀春 ; 李海燕

作者：

Zhang, Shihong ; Li, Zheng-Xiang ; Evans, David A. D. ; Wu, Huaichun ; Li, Haiyan ; Dong, Jin

单位：

China Univ Geosci, State Key Lab Biogeol & Environm Geol, Beijing 100083, Peoples R China;Curtin Univ Technol, Dept Appl Geol, ARC Ctr Excellence Core Crust Fluid Syst CCFS, Perth, WA, Australia;Curtin Univ Technol, Dept Appl Geol, Inst Geosci Res TIGeR, Perth, WA, Australia;Yale Univ, Dept Geol & Geophys, New Haven, CT 06520 USA

关键词：

paleomagnetism; Xiong'er Group; North China Block; Nuna; supercontinent; reconstruction

摘要：

The existence of a pre-Rodinia Precambrian supercontinent, variously called Nuna or Columbia, has been widely speculated in the past decade, but the precise timing of its existence and its configuration have been uncertain due to the lack of unequivocal paleomagnetic and geological constraints. Here we report high-quality paleomagnetic results from the well dated similar to 1780 Ma Xiong'er Group in southern North China Block (NCB). A total of 110 paleomagnetic samples from 14 sites were collected and subjected to stepwise thermal demagnetization. After removing a low temperature component (CL) of viscous magnetic remanence acquired in recent geomagnetic field, a high temperature component (CH), carried by hematite and magnetite in redbeds and volcanic samples, has been isolated. It gives a mean direction of (D=18.4 degrees, I=-3.7 degrees, alpha(95)=7.6 degrees, N=14) after bedding correction, and a corresponding paleomagnetic pole at 50.2 degrees N, 263.0 degrees E (A(95)=4.5 degrees). The CH passed a reversal test and was interpreted as a primary remanence. This new pole plus three other high-quality poles from the NCB that have been more precisely dated at 1769 +/- 3 Ma, 1560-1440 Ma and 1437 +/- 21 Ma define a 1780-1440 Ma apparent polar wander path (APWP) for the NCB. This, together with an update of global high quality paleomagnetic dataset, allows us to demonstrate that the pre-Rodinia supercontinent Nuna likely existed at least between similar to 1780 Ma and similar to 1400 Ma. Our paleomagnetism-based global reconstruction, for the first time, quantitatively assembles all major cratons together; it encompasses previously proposed regional links including the SAMBA connection between Baltica, Amazonia and Western Africa (Johansson, 2009), connections between Laurentia, Baltica and Siberia at the core of Nuna (Evans and Mitchell, 2011), the proto-SWEAT connection between Laurentia, East Antarctica and Australian blocks (Payne et al., 2009), and the NCB-India connection (Zhao et al., 2011). (C) 2012 Elsevier B.V. All rights reserved.

基金：

973 Program [2011CB808800]; NSFC [40921062, 40974035, 40032010B, 40830316]; SinoProbe Program; ARC [DP0770228]

语种：

英文

DOI：

10.1016/j.epsl.2012.07.034

来源：

EARTH AND PLANETARY SCIENCE LETTERS,2012():145-155.

出版日期：

2012-11-01

提交日期：

2017-12-14

引用参考：

Zhang, Shihong; Li, Zheng-Xiang; Evans, David A. D.; Wu, Huaichun; Li, Haiyan; Dong, Jin. Pre-Rodinia supercontinent Nuna shaping up: A global synthesis with new paleomagnetic results from North China[J]. EARTH AND PLANETARY SCIENCE LETTERS,2012():145-155.