文章基本信息

标题：Afar triple junction triggered by plume-assisted bi-directional continental break-up
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作者：Alexander Koptev ; Taras Gerya ; Eric Calais 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2018
卷号：8
期号：1
页码：14742
DOI：10.1038/s41598-018-33117-3
语种：English
出版社：Springer Nature
摘要：Divergent ridge-ridge-ridge (R-R-R) triple junctions are one of the most remarkable, yet largely enigmatic, features of plate tectonics. The juncture of the Arabian, Nubian, and Somalian plates is a type-example of the early development stage of a triple junction where three active rifts meet at a 'triple point' in Central Afar. This structure may result from the impingement of the Afar plume into a non-uniformly stressed continental lithosphere, but this process has never been reproduced by self-consistent plume-lithosphere interaction experiments. Here we use 3D thermo-mechanical numerical models to examine the initiation of plume-induced rift systems under variable far-field stress conditions. Whereas simple linear rift structures are preferred under uni-directional extension, we find that more complex patterns form in response to bi-directional extension, combining one or several R-R-R triple junctions. These triple junctions optimize the geometry of continental break-up by minimizing the amount of dissipative mechanical work required to accommodate multi-directional extension. Our models suggest that Afar-like triple junctions are an end-member mode of plume-induced bi-directional rifting that combines asymmetrical northward pull and symmetrical EW extension at similar rates.