Article ID Journal Published Year Pages File Type
4722833 Precambrian Research 2015 13 Pages PDF
Abstract

•New paleomagnetic results obtained from the Doushantuo Formation in South China.•Previously published Doushantuo pole reflects a Paleozoic remagnetization.•South China Block moved around NW Australia during late Ediacaran time.

A new paleomagnetic pole is obtained from the top of Member 3 of the Doushantuo Formation in the Jiulongwan section of the Yangtze Gorges area in South China. A total of 191 samples from 23 sites were collected and subjected to stepwise alternating field (AF) and thermal demagnetization. After the removal of a soft component (SC) of viscous magnetic remanence acquired in present geomagnetic field, a high temperature component (HC), likely carried by magnetite, was isolated. The HC includes vectors from 147 samples using principal component analysis and arc constraints from 44 samples using remagnetization great-circle analysis. Both the vectors only and the combined vectors and arc constraints of the HC passed a reversal test. This is the first Ediacaran paleomagnetic remanence from the South China Block (SCB) that passes a reversal test, and it is interpreted as a primary remanence. The HC vectors were thus used to calculate the paleomagnetic pole, and in combination with arc constraints, were used for polarity interpretation. The vectors give a mean direction of (D = 75.2°, I = 41.0°, α95 = 2.5°, N = 147) after bedding correction, and a corresponding paleomagnetic pole at 23.9° N, 187.0° E (dm/dp = 3.0/1.8). This pole differs significantly from previously published results of the Doushantuo Formation, which may have been subjected to Paleozoic remagnetization. Our results provide a 23.5 ± 1.8° N paleolatitude for the Yangtze Gorges area of the SCB and suggest several alternative paleogeographic options for the Ediacaran–Cambrian amalgamation of East Gondwana, depending on chronostratigraphic correlations.

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Physical Sciences and Engineering Earth and Planetary Sciences Geochemistry and Petrology
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