Prof. Tomoo Katsura [University Bayreuth, Germany]

Prof. Tomoo Katsura [Bayerishes Geoinstitut, University Bayreuth, Germany]

Title: Davemaoite does exist in the lower mantle

Language:  English presentation

Time: Beijing, 15:00 - 16:00 PM, Wednesday, September 11, 2024

Place:  Onsite：Conference room A417, HPSTAR (Beijing)

            Online:  Tencent Meeting: https://meeting.tencent.com/dm/MFc41vlmW31h  Meeting ID: 821-197-791

Host:  Prof. Yang Ding

Abstract:

Davemaoite, a CaSiO3 perovskite, is believed to be the third most abundant mineral in Earth's lower mantle and is essential for understanding its chemical evolution and dynamics. However, the presence of davemaoite in the lower mantle remains a subject of debate. A recent study using laser-heated diamond anvil cells (LH-DAC) reported that the solubility of Ca in bridgmanite increases significantly above 2300 K and 40 GPa. This led to the conclusion that davemaoite is absent in regions deeper than 1,800 km in Earth's mantle. To verify this conclusion, we conducted multi-anvil experiments at pressures ranging from 27 to 50 GPa and temperatures between 2300 and 2700 K, using various compositions. Our results demonstrate that the Ca solubility in bridgmanite cannot eliminate davemaoite under typical mantle conditions, including representative pressure, temperature, and chemical compositions. Based on our findings, we conclude that davemaoite does indeed exist in Earth's lower mantle, contrary to the previous study's suggestion.

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