Diamond anvil cell experiments applied to the geochemistry of Earth's core formation (Invited)
Abstract
The abundances of siderophile elements in the Earth's mantle bear the imprint of the core formation in the early Earth. Thermodynamic expressions used to constrain the metal-silicate partitioning behavior of siderophile elements are mainly established from large volume press experiments that do not adequately cover the full range of potential P-T conditions for core-mantle equilibrium. The diamond anvil cell is the only static-pressure generating device capable of achieving required P-T conditions but, until now, its capabilities to perform quantitative metal-silicate partitioning experiments at extreme conditions has been almost untapped. Here we use protocols that effectively link high P-T diamond anvil cell runs with analytical techniques such as focused ion beam device (FIB), NanoSIMS, electron microprobe, transmission electron microscope, and in-situ synchrotron X-ray diffraction measurements. These techniques allow us to obtain quantitative data on element partitioning at superliquidus conditions above 30 GPa and 3000 K. Preliminary experimental results and technical advances in both experimental and analytical methods will be discussed. We have investigated the partitioning of 6 siderophile elements (Ni, Co, Cr, V, Mn, and Nb) that have been extensively studied at lower P-T conditions. We have also constrained the solubility of light elements (Si and O) at these extreme conditions. The new data are used to update previous expressions that describe the partitioning behavior of these elements and enable us to address the validity of proposed core formation models (i.e. single-stage core formation model and continuous core formation model).
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.V44B..04S
- Keywords:
-
- 1015 GEOCHEMISTRY / Composition of the core;
- 3630 MINERALOGY AND PETROLOGY / Experimental mineralogy and petrology