The Structural and Bonding Behavior of 3d Transitional Metal Carbonates at Mantle Pressures

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Abstract/Contents

Abstract: Carbonate minerals are potentially major hosts for carbon in the lower mantle of the Earth. Since the mantle holds 100 times more carbon than the crust, atmosphere, and ocean reservoirs, a thorough understanding of the deep carbon cycle is necessary to model the global carbon cycle. High pressure studies are important because they help us define the stability of crystal phases that exist at extreme conditions and how these new carbonate structures hold carbon in the deep carbon cycle. Fe2+, the 3d transition metal in siderite (FeCO3), undergoes a coupled electronic spin transition and an isostructural phase transition at approximately 46 GPa, as well as a later structural phase transition at ~100 GPa. In contrast, Mn2+ in rhodochrosite (MnCO3) undergoes a structural phase transition to an orthorhombic structure at approximately 50 GPa and an electronic spin transition at ~100 GPa. These transitions were observed using in-situ Raman spectroscopy and X-ray diffraction coupled with high-pressure diamond anvil cells. Studies of electronic spin and structural phase transitions in carbonates are crucial for developing the phase diagrams and understanding the properties under the extreme conditions in the deep Earth that govern the stability and behavior of carbonates as possible hosts for carbon in the lower mantle.

Type of resource	text
Date created	May 2013

Author	Farfan, Gabriela Aylin
Primary advisor	Mao, Wendy
Advisor	Brown, Gordon
Degree granting institution	Stanford University, Department of Geological and Environmental Sciences

Subject	School of Earth Energy & Environmental Sciences
Subject	deep carbon
Genre	Thesis

Location	https://purl.stanford.edu/nq711kx0849

Use and reproduction: Theses courtesy of Stanford University Libraries. If you have questions, please contact the Branner Earth Science Library & Map Collections at brannerlibrary@stanford.edu.

Preferred Citation: Farfan, Gabriela Aylin. (2013). The Structural and Bonding Behavior of 3d Transitional Metal Carbonates at Mantle Pressures. Stanford Digital Repository. Available at: http://purl.stanford.edu/nq711kx0849

Undergraduate Honors Theses, Doerr School of Sustainability

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