SM-ND Age and REE Systematics of Larkman Nunatek 06319: Closed System Fractional Crystallization of a Shergottite Magma

Summary: The Sm-Nd age of LAR 06319 is 180±13 Ma, which corresponds well to other measured radiogenic ages on this rock and with the ages of other shergottites that it appears to be genetically related to. Measured LA-ICP-MS REE element abundances of pyroxenes are in good agreement with modeled com-positions derived from fractional crystallization of a parent magma with whole-rock REE contents equiva-lent to a melt inclusion in the core of a large olivine phenocryst. These trace element results are consistent with progressive closed-system fractional crystalliza-tion of a single magma, which implies that the isotopic results are indeed reflecting the true crystallization age of LAR 06319 and that the enriched shergottite source was producing magmas late in Martian history. References: [1] Shafer J.T. et al. (2009) LPS XXXX , Abstract #1803. [2] Shih C.-Y. et al. (2009) LPS XXXX , Abstract #1360. [3] Peslier A.H. et al. (2009) submitted. [4] Sarbadhikari A.B. et al. (2009)