Vastly Different Heights of LLVPs Caused by Different Strengths of Historical Slab Push

Qian Yuan, Mingming Li

Research output: Contribution to journalArticlepeer-review

Abstract

Two large low velocity provinces (LLVPs) are observed in Earth's lower mantle, beneath Africa and the Pacific Ocean, respectively. The maximum height of the African LLVP is ∼1,000 km larger than that of the Pacific LLVP, but what causes this height difference remains unclear. LLVPs are often interpreted as thermochemical piles whose morphology is greatly controlled by the surrounding mantle flow. Seismic observations have revealed that while some subducted slabs are laterally deflected at ∼660–1,200 km, other slabs penetrate into the lowermost mantle. Here, through geodynamic modeling experiments, we show that rapid sinking of stagnant slabs to the lowermost mantle can cause significant height increases of nearby thermochemical piles. Our results suggest that the African LLVP may have been pushed more strongly and longer by surrounding mantle flows to reach a much shallower depth than the Pacific LLVP, perhaps since the Tethys slabs sank to the lowermost mantle.

Original languageEnglish (US)
Article numbere2022GL099564
JournalGeophysical Research Letters
Volume49
Issue number17
DOIs
StatePublished - Sep 16 2022

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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