Premium
Salts in two chondritic porous interplanetary dust particles
Author(s) -
Rietmeijer Frans J. M.
Publication year - 1990
Publication title -
meteoritics
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0026-1114
DOI - 10.1111/j.1945-5100.1990.tb00998.x
Subject(s) - interplanetary dust cloud , chondrite , magnesite , mineralogy , chemistry , carbonate , astrobiology , geology , geochemistry , magnesium , meteorite , solar system , physics , organic chemistry
— Grain‐by‐grain analytical electron microscope analyses of two micrometeorites, or interplanetary dust particles (IDPs), of the chondritic porous subtype, show the presence of rare barite (BaSO 4 ) and magnesium carbonate, probably magnesite. Salt minerals in chondritic porous (CP) IDPs give evidence for in situ aqueous alteration in their parent bodies. The uniquely high barium content of CP IDP W7029 * C1 is consistent with barite precipitation from a mildly acidic (pH > ∼5) aqueous fluid at temperatures below 417 K and low oxygen fugacity. The presence of magnesite in olivine‐rich, anhydrous CP IDP W7010 * A2 is evidence that carbonate minerals occur in both the chondritic porous and chondritic smooth subtypes of chondritic IDPs. Citing Schramm et al. (1989) for putative asteroidal‐type aqueous alteration in IDPs and probable sources of chondritic IDPs, salt minerals in CP IDPs could support low‐temperature aqueous activity in nuclei of active short‐period comets.