The chemical composition and homogeneity of the Allende matrix

Abstract

The abundances of C, O, S, Na, K, Li, Mn, P, Cr, Si, Fe, Mg, Ni, Co, V, Ca, Ti, Al and Sc were determined in-situ in a sample of the Allende meteorite using a laser ablation/ionization mass spectrometer to quantify the bulk chemical composition of the matrix and its spatial chemical variability.The high lateral resolution of the instrument makes it possible to measure the elemental composition of Allende matrix, without any sample treatment prior to analysis. The measurements of solely Allende matrix allow investigating the variability of the element abundances in the matrix material on different scales from 50 ​μm to 0.5 ​mm.The comprehensive data set provides constraints on models for the formation of matrix material of carbonaceous chondrites in the solar nebula. A key observation of this study is a high degree of chemical homogeneity of the matrix, indicating that it formed independently from or in parallel with the chondrules and that the process that led to the formation of the parent body was a fast collapse of the dust-gas cloud following chondrule formation.