A Sintered and Sulfidized Equilibrated Aggregate from an Interplanetary Dust Particle

indicative of melting and formation of minerals under a variety of conditions (fO2, T, P). In this work, we study an EA from an interplanetary dust particle (L2071 cluster 12, “Humpty and Dumpty”) captured by a stratospheric flight over North America in 2008. We prepared it using a Focused Ion Beam (FIB), and examined it using the TitanX Transmission Electron Microscope (TEM) at the Molecular Foundry in Berkeley, CA. Figure 1A shows the EA with a pyrrhotite/metal core which is Fe-rich on the left (red), and Ni-rich on the right (blue), and silicates (green). The small boxed area contains fine-grained silicates also shown in Figure 1B. Figure 1B is colored using Non-negative Matrix Factorization (NMF) of the EDS map. Olivine and kosmochloric [Joswiak] clinopyroxene (CPX) crystals are embedded in an Al-, Si-rich glass. The Mg# varies from 73 to 83 depending on the phase. See compositions in Table 1. Phase identifications are based on EDS with the exception of the large olivine and pyrrhotite which are confirmed by electron diffraction as well.