Constraints on the Ediacaran inertial interchange true polar wander hypothesis: A new paleomagnetic study in Morocco (West African Craton)

2017 ◽  
Vol 295 ◽  
pp. 90-116 ◽  
Author(s):  
B. Robert ◽  
J. Besse ◽  
O. Blein ◽  
M. Greff-Lefftz ◽  
T. Baudin ◽  
...  
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>


2009 ◽  
Vol 4 ◽  
pp. 313-327 ◽  
Author(s):  
W. Harbert ◽  
N. V. Tsukanov ◽  
D. V. Alexeiev ◽  
C. Gaedicke ◽  
R. Freitag ◽  
...  

Abstract. The Kamchatka Peninsula of northeastern Russia is located along the northwestern margin of the Bering Sea and consists of zones of complexly deformed accreted terranes. Paleomagnetic samples were collected for study from a Late Cretaceous aged locality at Cape Kronotskiy (λ=54°44.8´ N, φ=162°1.29´ E). Two components of magnetization were observed. During stepwise thermal demagnetization, the B-magnetic component was observed up to 600°C having a direction and associated uncertainty in stratigraphic coordinates of Ds=300.7°, Is=48.7°, α95=10.9°, k-value=11.8, n=17. The B component paleolatitude calculated from the Fisher mean in stratigraphic coordinates and associated statistics are λobs=30.4° N or S, λ95=8.9°, n=17 (sites), k-value=11. Our overall study paleolatitude result is similar to a previously reported paleomagnetic study completed within this unit. Terrane trajectories calculated using the finite rotation poles of Engebretson et al. (1985), which are corrected for either Pacific-hotspot drift or True Polar Wander hotspot-spin axis relative motion, show that the sampled unit represents a far traveled tectonostratigraphic terrane and support a model in which accretion (docking) events of this composite or superterrane with the North America plate occur at approximately 40 Ma.


2002 ◽  
Vol 107 (B10) ◽  
pp. ETG 16-1-ETG 16-17 ◽  
Author(s):  
R. Sabadini ◽  
A. M. Marotta ◽  
R. De Franco ◽  
L. L. A. Vermeersen

Science ◽  
2000 ◽  
Vol 288 (5475) ◽  
pp. 2283a-2283 ◽  
Author(s):  
R. D. Cottrell

2008 ◽  
Vol 297 (1) ◽  
pp. 329-343 ◽  
Author(s):  
H. Ezzouhairi ◽  
M. L. Ribeiro ◽  
N. Ait Ayad ◽  
M. E. Moreira ◽  
A. Charif ◽  
...  

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