Inverted South China: A novel configuration for Rodinia and its breakup

Geology ◽  
2020 ◽  
Author(s):  
Xianqing Jing ◽  
David A.D. Evans ◽  
Zhenyu Yang ◽  
Yabo Tong ◽  
Yingchao Xu ◽  
...  

Disentangling records of Rodinia fragmentation and true polar wander remains a challenge for understanding late Tonian plate tectonics. The ca. 760 Ma lower member of the Liántuó Formation, South China, yields a primary paleomagnetic remanence that passes both the fold and reversal tests. This new result and recently reported ca. 800 Ma data from elsewhere in South China suggest a new interpretation of its apparent polar wander path, whereby pre–770 Ma poles have inverted absolute polarity relative to traditional interpretations. Based on this inversion, and an interpretation of several oscillations of true polar wander documented by global data during 810–760 Ma, we propose a novel reconstruction for Rodinia and its breakup. Our reconstruction places the South China, India, and Kalahari cratons to the southwest of Laurentia, with connections that might have been established as early as ca. 1000 Ma. Our model also suggests that initial rifting of Rodinia occurred at ca. 800 Ma via fast northward motion of the India craton and South China.

2019 ◽  
Vol 132 (3-4) ◽  
pp. 710-738 ◽  
Author(s):  
Athena Eyster ◽  
Benjamin P. Weiss ◽  
Karl Karlstrom ◽  
Francis A. Macdonald

AbstractPaleogeographic models commonly assume that the supercontinent Rodinia was long-lived, with a static geometry involving Mesoproterozoic links that developed during assembly and persisted until Neoproterozoic rifting. However, Rodinian paleogeography and dynamics of continental separation around its centerpiece, Laurentia, remain poorly constrained. On the western Laurentian margin, geological and geochronological data suggest that breakup did not occur until after 720 Ma. Thus, late Tonian (ca. 780–720 Ma) paleomagnetic data are critical for reconstructing paleogeography prior to dispersal and assessing the proposed stasis of Rodinia. Here, we report new paleomagnetic data from the late Tonian Chuar Group in the Grand Canyon, Arizona. We combined this new data set with reanalyzed existing data to obtain a new paleopole preserved in hematite, the reliability of which is supported by six of the seven (Q1–Q6) Van der Voo reliability quality criteria. In addition, we identified pervasive mid- to high-temperature overprints. This new paleomagnetic pole was incorporated with recent high-precision geochronological data and existing paleomagnetic data to present a new late Tonian Laurentian apparent polar wander path (APWP). Having examined the paleomagnetic data of other cratons, global reconstructions for 775 Ma, 751 Ma, and 716 Ma are presented. These reconstructions are consistent with Australia located near the present southern margin of Laurentia. However, a stringent analysis of the global data set does not support a good match between any major craton and the rifted conjugate margin to western Laurentia. Breakup on the western Laurentian margin may have involved rifting of a continental fragment or a craton with uncertainties in its late Tonian geochronologic and paleomagnetic constraints. Our revised Laurentian APWP will allow for more robust tests of paleogeography and evaluation of the proposed supercontinent Rodinia.


1991 ◽  
Vol 96 (B3) ◽  
pp. 4007-4027 ◽  
Author(s):  
Randolph J. Enkin ◽  
Yan Chen ◽  
Vincent Courtillot ◽  
Jean Besse ◽  
Lisheng Xing ◽  
...  

2021 ◽  
Author(s):  
Justin Tonti-Filippini ◽  
Boris Robert ◽  
Élodie Muller ◽  
Michael Wack ◽  
Xixi Zhao ◽  
...  

<p>The paleomagnetic record during the middle Neoproterozoic (~825-780 Ma) displays rapid apparent polar wander variations leading to large discrepancies in paleogeographic reconstructions. Some authors propose that these data may represent true polar wander events, which correspond to independent motion of the mantle and lithosphere with respect to Earth’s rotation axis. An alternative explanation might be a perturbation of the geomagnetic field, such as a deviation from a predominantly dipole field or a hyper-reversing field. To test these hypotheses, we sampled 1200 oriented cores over a stratigraphic height of 100 metres in sedimentary rocks of the 820-810 Ma Laoshanya Formation in South China. We will present preliminary paleomagnetic and rock magnetic analyses together with results of petrologic and geochemical experiments to better understand the origin of the paleomagnetic signal.</p>


2008 ◽  
Vol 169 (1-4) ◽  
pp. 166-177 ◽  
Author(s):  
Stuart A. Gilder ◽  
Xiaodong Tan ◽  
Hugo Bucher ◽  
Guodun Kuang ◽  
Jiarun Yin
Keyword(s):  

Icarus ◽  
2017 ◽  
Vol 286 ◽  
pp. 153-192 ◽  
Author(s):  
Michael Nayak ◽  
Doug Hemingway ◽  
Ian Garrick-Bethell

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