地质学
地幔(地质学)
过渡带
玄武岩
大洋地壳
俯冲
结壳
厚板
地幔对流
地球物理学
埃达克岩
地幔楔
岩石学
地球化学
构造学
地震学
作者
Benoit Tauzin,Lauren Waszek,Maxim D. Ballmer,Juan Carlos Afonso,Thomas Bodin
标识
DOI:10.1073/pnas.2209399119
摘要
The formation and preservation of compositional heterogeneities inside the Earth affect mantle convection patterns globally and control the long-term evolution of geochemical reservoirs. However, the distribution, nature, and size of reservoirs in the Earth's mantle are poorly constrained. Here, we invert measurements of travel times and amplitudes of seismic waves interacting with mineralogical phase transitions at 400-700-km depth to obtain global probabilistic maps of temperature and bulk composition. We find large basalt-rich pools (up to 60% basalt fraction) surrounding the Pacific Ocean, which we relate to the segregation of oceanic crust from slabs that have been subducted since the Mesozoic. Segregation of oceanic crust from initially cold and stiff slabs may be facilitated by the presence of a weak hydrated layer in the slab or by weakening upon mineralogical transition due to grain-size reduction.
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