Origin of supposedly biogenic magnetite in the Martian meteorite Allan Hills 84001.

BIOGENIC OR ABIOGENIC ORIGIN OF CARBONATE-MAGNETITE-SULFIDE ASSEMBLAGES IN MARTIAN METEORITE ALLAN HILLS 84001. E. R. D. Scott, Hawai’i Institute of Geophysics and Planetol-

Carbonates in the Martian meteorite Allan Hills 84001 formed at 18 4 °C in a near-surface aqueous environment

Despite evidence for liquid water at the surface of Mars during the Noachian epoch, the temperature of early aqueous environments has been impossible to establish, raising questions of whether the surface of Mars was ever warmer than today. We address this problem by determining the precipitation temperature of secondary carbonate minerals preserved in the oldest known sample of Mars’ crust—the...

Combining meteorites and missions to explore Mars.

Laboratory studies of meteorites and robotic exploration of Mars reveal scant atmosphere, no evidence of plate tectonics, past evidence for abundant water, and a protracted igneous evolution. Despite indirect hints, direct evidence of a martian origin came with the discovery of trapped atmospheric gases in one meteorite. Since then, the study of martian meteorites and findings from missions hav...

Carbonates in the Martian meteorite

Despite evidence for liquid water at the surface of Mars during the Noachian epoch, the temperature of early aqueous environments has been impossible to establish, raising questions of whether the surface of Mars was ever warmer than today. We address this problem by determining the precipitation temperature of secondary carbonate minerals preserved in the oldest known sample of Mars’ crust—the...

Thermal Decomposition of an Impure (roxbury) Siderite: Relevance to the Presence of Chemically Pure Magnetite Crystals in Alh84001 Carbonate Disks

Background and Introduction: The question of the origin of nanophase magnetite in Martian meteorite ALH84001 has been widely debated for nearly a decade. Golden et al. [1] have reported producing nearly chemically pure magnetite from thermal decomposition of chemically impure siderite [(Fe, Mg, Mn)CO3]. This claim is significant for three reasons: first, it has been argued that chemically pure ...