Vastly Different Heights of LLVPs Caused by Different Strengths of Historical Slab Push
- Creators
- Yuan, Qian
- Li, Mingming
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.
Additional Information
We are grateful for the extensive discussions with Edward Garnero, Sang-Heon Shim and Daniel Portner. Constructive comments from two anonymous reviewers are greatly appreciated. The authors particularly thank Thorsten Becker for suggestions and providing the digital form of Figure 4. The numerical models are performed on the Agave cluster at Arizona State University. This work is supported by National Science Foundation grants of EAR-1849949, EAR-1855624, and EAR-2200335.Additional details
- Eprint ID
- 117009
- Resolver ID
- CaltechAUTHORS:20220916-663995000
- EAR-1849949
- NSF
- EAR-1855624
- NSF
- EAR-2200335
- NSF
- Created
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2022-12-03Created from EPrint's datestamp field
- Updated
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2022-12-04Created from EPrint's last_modified field
- Caltech groups
- Seismological Laboratory