scholarly journals A consistently high latitude South China from 820 to 780 Ma: Implications for exclusion from Rodinia and the feasibility of large‐scale true polar wander

2021 ◽  
Author(s):  
Yuem Park ◽  
Nicholas L. Swanson‐Hysell ◽  
Hanbiao Xian ◽  
Shihong Zhang ◽  
Daniel J. Condon ◽  
...  
Keyword(s):  
South China ◽  
High Latitude ◽  
Large Scale ◽  
Polar Wander ◽  
True Polar Wander

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 ◽  
...  
Keyword(s):  
South China ◽  
Plate Tectonics ◽  
The South ◽  
Polar Wander ◽  
True Polar Wander ◽  
Apparent Polar Wander Path ◽  
Lower Member ◽  
New Interpretation ◽  
Global Data

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.

The Neoproterozoic geomagnetic field: new insights from a high-resolution paleomagnetic study in South China

2021 ◽  
Author(s):  
Justin Tonti-Filippini ◽  
Boris Robert ◽  
Élodie Muller ◽  
Michael Wack ◽  
Xixi Zhao ◽  
...  
Keyword(s):  
South China ◽  
Geomagnetic Field ◽  
Alternative Explanation ◽  
Rotation Axis ◽  
Sedimentary Rocks ◽  
Polar Wander ◽  
True Polar Wander ◽  
Paleomagnetic Study ◽  
Stratigraphic Height ◽  
Independent Motion

<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>

A true polar wander trigger for the Great Jurassic East Asian Aridification

Geology ◽  
2019 ◽  
Vol 47 (12) ◽  
pp. 1112-1116 ◽  
Author(s):  
Zhiyu Yi ◽  
Yongqing Liu ◽  
Joseph G. Meert
Keyword(s):  
Environmental Change ◽  
East Asia ◽  
Late Jurassic ◽  
Large Scale ◽  
Arid Zone ◽  
East Asian ◽  
Volcanic Rocks ◽  
Jehol Biota ◽  
Polar Wander ◽  
True Polar Wander

Abstract A drastic environmental change occurred during the Middle to Late Jurassic as much of East Asia transitioned from a wet seasonal to an extremely arid climate. The timing, scope, and especially mechanism for this aridification are contentious. In this study, we report paleomagnetic data and ages from Jurassic volcanic rocks in North China and for the first time reveal a large-scale southward displacement of ∼25° for the Eastern Asian blocks (EABs) sometime between 174 ± 6 Ma and 157 ± 4 Ma. We suggest that the rapid motion documented by our paleomagnetic studies resulted from large-scale true polar wander (TPW). The TPW rotation displaced the EABs from the Northern Hemisphere humid-temperate belt into the subtropical/tropical arid zone. The resultant latitudinal motion coincided with a remarkable environmental change recorded over 10,000,000 km2 in East Asia between ca. 165 Ma and 155 Ma. We call the climate transition the “Great Jurassic East Asian Aridification” and argue that TPW-induced climatic shifts were also responsible for the demise of the Yanliao Biota and subsequent radiation of the Jehol Biota during the Late Jurassic and Early Cretaceous.

scholarly journals A Late Cretaceous true polar wander oscillation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ross N. Mitchell ◽  
Christopher J. Thissen ◽  
David A. D. Evans ◽  
Sarah P. Slotznick ◽  
Rodolfo Coccioni ◽  
...  
Keyword(s):  
High Resolution ◽  
Late Cretaceous ◽  
Plate Tectonics ◽  
Large Scale ◽  
Spin Axis ◽  
Polar Wander ◽  
The Past ◽  
True Polar Wander ◽  
Palaeomagnetic Data

AbstractTrue polar wander (TPW), or planetary reorientation, is well documented for other planets and moons and for Earth at present day with satellites, but testing its prevalence in Earth’s past is complicated by simultaneous motions due to plate tectonics. Debate has surrounded the existence of Late Cretaceous TPW ca. 84 million years ago (Ma). Classic palaeomagnetic data from the Scaglia Rossa limestone of Italy are the primary argument against the existence of ca. 84 Ma TPW. Here we present a new high-resolution palaeomagnetic record from two overlapping stratigraphic sections in Italy that provides evidence for a ~12° TPW oscillation from 86 to 78 Ma. This observation represents the most recent large-scale TPW documented and challenges the notion that the spin axis has been largely stable over the past 100 million years.

Sign in / Sign up

Export Citation Format

Share Document