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Carbonates in Martian meteorite ALH84001: A planetary perspective on formation temperature
Author(s) -
Hutchins Kevin S.,
Jakosky Bruce M.
Publication year - 1997
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/97gl00686
Subject(s) - martian , meteorite , astrobiology , isotopes of oxygen , mars exploration program , atmosphere (unit) , atmosphere of mars , hydrothermal circulation , groundwater , geology , salinity , isotopes of carbon , oxygen , stable isotope ratio , earth science , atmospheric sciences , environmental chemistry , geochemistry , chemistry , paleontology , oceanography , total organic carbon , thermodynamics , physics , geotechnical engineering , organic chemistry , quantum mechanics
We have re‐examined the formation temperature of carbonates in ALH84001, accounting for the prior evolution of the stable isotopes used in the analysis. Oxygen and carbon in the atmosphere likely have become isotopically fractionated due to various nonthermal loss mechanisms operating throughout geologic time. Taking this previous evolution into account, we derive a formation temperature from oxygen isotope thermometry of 40–250 °C. This range of temperatures represents a lower limit; an increase in groundwater salinity could further raise the δ 18 O of the groundwater, as seen in terrestrial hydrothermal systems, allowing for an even higher temperature of formation derived from the isotopic data.