Abstract: | Abstract— Submicron platey Sn-rich grains are present in chondritic porous interplanetary dust particle (IDP) W7029*A and it is the second occurrence of a tin mineral in a stratospheric micrometeorite. Selected Area Electron Diffraction data for the Snrich grains match with Sn2O3 and Sn3O4. The oxide(s) may have formed in the solar nebula when tin metal catalytically supported reduction of CO or during flash heating on atmospheric entry of the IDP. The presence of tin is consistent with enrichments for other volatile trace elements in chondritic IDPs and may signal an emerging trend towards non-chondritic volatile element abundances in chondritic IDPs. The observation confirms small-scale mineralogical heterogeneity in fine-grained chondritic porous interplanetary dust. |