The elemental composition of Almahata Sitta

Abstract

We quantified up to 60 elements in four individual fragments (#4, #7, #15, and #47) of the Almahata Sitta meteorite, which entered Earth's atmosphere on October 7, 2008. Almahata Sitta is indisputably the product of fragments of asteroid 2008 TC3 surviving passage through Earth's atmosphere. Each of the four analyzed fragments has a ureilitic composition based on comparisons with literature data. The analyzed fragments represent each of the major lithologies of Almahata Sitta. Highly refractory siderophile elements are similarly enriched in all fragments of Almahata Sitta, while volatile elements show more compositional variability. The abundances of rare earth elements (REE) only reach CI values in the case of a single Almahata Sitta fragment (#15). More typically, REE abundances in Almahata Sitta are between 0.01 and 0.3 × CI. None of the fragments displays the classic V-shaped REE pattern that are often found in ureilites. Given that Almahata Sitta was collected shortly after its fall, these REE compositional results indicate that the V-shaped REE pattern found in many ureilites may be a result of extended terrestrial residence times. © The Meteoritical Society, 2010.