کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6433080 | 1635750 | 2016 | 17 صفحه PDF | دانلود رایگان |
- Plume-lid tectonics operated in the early Earth before plate tectonics.
- Plume-lid tectonics is driven by small-scale convection and lithospheric dripping.
- Plume-lid tectonics produces the typical Archean dome-and-keel structures.
Geological-geochemical evidence point towards higher mantle potential temperature and a different type of tectonics (global plume-lid tectonics) in the early Earth (>3.2Â Ga) compared to the present day (global plate tectonics). In order to investigate tectono-magmatic processes associated with plume-lid tectonics and crustal growth under hotter mantle temperature conditions, we conduct a series of 3D high-resolution magmatic-thermomechanical models with the finite-difference code I3ELVIS. No external plate tectonic forces are applied to isolate 3D effects of various plume-lithosphere and crust-mantle interactions. Results of the numerical experiments show two distinct phases in coupled crust-mantle evolution: (1) a longer (80-100Â Myr) and relatively quiet 'growth phase' which is marked by growth of crust and lithosphere, followed by (2) a short (â¼20Â Myr) and catastrophic 'removal phase', where unstable parts of the crust and mantle lithosphere are removed by eclogitic dripping and later delamination. This modelling suggests that the early Earth plume-lid tectonic regime followed a pattern of episodic growth and removal also called episodic overturn with a periodicity of â¼100Â Myr.
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Journal: Journal of Geodynamics - Volume 100, October 2016, Pages 198-214