Partition and Diffusion of REE and HFSE in Pyroxene
Pyroxene is a major rock-forming mineral in the Earth's upper mantle and lower crust and has played a crucial role in the generation and differentiation of mafic and ultramafic rocks in the Earth, Moon, Mars, and other planetary bodies. The distribution of rare earth elements (REE) and high-field strength elements (HFSE) between pyroxene and basaltic melt is important in deciphering mantle melting processes and has been a subject of numerous experimental and theoretical studies. We have undertaken a systematic study of REE and HFES partitioning between pyroxene and basaltic melts and between orthopyroxene and clinopyroxene in coexisting mafic and ultramafic rocks. The purposes of these studies are (1) to develop internally consistent models that can be used to predict pyroxene-melt REE and HFSE partition coefficients that are relevant to mantle melting and (2) to develop a REE-in-two-pyroxene thermometer for mafic and ultramafic rocks. Parallel to our partitioning studies, we have also examined the diffusion of REE and Ti in pyroxene. Given REE and HFSE diffusion and partition coefficients, it is possible to develop models that can be used to assess the cooling rate of mafic and ultramafic rocks.
Brown faculty collaborators:
Other project collaborators:Chenguang Sun, Lijing Yao, Daniele Cherniak
Figure 1. Comparison between temperatures derived from the REE-in-two-pyroxene thermometer (T REE) and those calculated using the major element based two-pyroxene thermometer of Brey and Köhler (1990, T BKN, assuming a pressure of 1.5 GPa) for well-equilibrated spinel lherzolite and harzburgite xenoliths reported in the literature.Back to Yan Liang's Brown Research Profile