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Thermochemical Structure and Dynamics of Earth's Lowermost Mantle


Abstract Seismic observations have revealed two large low shear velocity provinces (LLSVPs) in the lowermost mantle beneath Pacific and Africa. One hypothesis for the origin of LLSVPs is that they are caused by accumulation of subducted oceanic crust on the core-mantle boundary (CMB). Here, I perform high resolution geodynamical calculations to test this hypothesis. The result shows that it is difficult for a thin (~ 6 km) subducted oceanic crust to accumulate on the CMB, and the major part of it is viscously stirred into the surrounding mantle. Another hypothesis for the origin of LLSVPs is that they are caused by thermochemical piles of more-primitive material which is remnant of Earth's early differentiation. In such case, a significant part ... (more)
Created Date 2015
Contributor Li, Mingming (Author) / McNamara, Allen K (Advisor) / Garnero, Edward J (Committee member) / Shim, Sang-Heon (Committee member) / Tyburczy, James (Committee member) / Clarke, Amanda (Committee member) / Arizona State University (Publisher)
Subject Geology / Geophysics / LLSVP / lowermost mantle / more-primitive material / numerical modeling / subducted oceanic crust / ULVZ
Type Doctoral Dissertation
Extent 205 pages
Language English
Note Doctoral Dissertation Geological Sciences 2015
Collaborating Institutions Graduate College / ASU Library
Additional Formats MODS / OAI Dublin Core / RIS


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Description Dissertation/Thesis