Magma-assisted fragmentation of Pangea: Continental breakup initiation and propagation

Type Article
Date 2021-08
Language English
Author(s) Guan Huixin1, 2, 3, Geoffroy Laurent4, 5, Xu Min1, 2, 3
Affiliation(s) 1 : Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou 511458, China
2 : Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China
3 : China-Pakistan Joint Research Centre on Earth Sciences, CAS-HEC, Islamabad 45320, Pakistan
4 : Université de Bretagne Occidentale, Brest 29238, France
5 : CNRS, UMR 6538, Laboratoire Domaines Océaniques, 29280 Plouzané, France
Source Gondwana Research (1342-937X) (Elsevier), 2021-08 , Vol. 96 , P. 56-75
DOI 10.1016/j.gr.2021.04.003
WOS© Times Cited 7
Keyword(s) Supercontinents, Volcanic passive margin, Non-volcanic passive margin, Large igneous province, Pangea, Breakup propagation
Abstract

Pre-magmatic continental extension often precedes the major magmatic expulsion of large igneous provinces (LIPs). However, the cause-and-effect relationship between pre-magmatic rifting and the extrusion of large amount of magma is controversial. It remains unclear whether magmatism arises as a consequence of passive rifting or whether it is related to active upwelling of the mantle. In addition, the relationship between the pre-magmatic stages and the final breakup, with the onset of conjugate passive margins, is ambiguous. In this study, we compiled available data from six LIPs (Central Atlantic, Karoo, Parana-Etendeka, Deccan, North Atlantic, and Afar igneous provinces) that successively occurred during the fragmentation of Pangea and found that pre-magmatic rift trends may show a high obliquity or even be orthogonal with respect to the future passive margins. We conclude that syn-magmatic rifts should not be directly correlated, both structurally and dynamically, to the ancient pre-magmatic rift phase. Furthermore, following the breakup of a supercontinent, seafloor spreading usually initiates within volcanic passive margins (VPMs) and then propagates away to create non-volcanic passive margins (NVPMs) as a consequence of the consumption and cooling of a sub-lithospheric positive thermal anomaly. Major transform faults often exist between VPMs and NVPMs, acting as a mechanical barrier to mantle melting and magmatism transportation. (c) 2021 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

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