Magnetofossils from ancient Mars: a robust biosignature in the martian meteorite ALH84001.
نویسندگان
چکیده
Magnetofossils from Ancient Mars: a Robust Biosignature in the Martian Meteorite ALH84001 Kathie L. Thomas-Keprta,* Simon J. Clemett, Dennis A. Bazylinski, Joseph L. Kirschvink, David S. McKay, Susan J. Wentworth, Hojatollah Vali, Everett K. Gibson, Jr., and Christopher S. Romanek Lockheed Martin and National Aeronautics and Space Adminstration/Johnson Space Center, Houston, Texas 77058; Department of Microbiology, Iowa State University, Ames, Iowa 50011; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125; Department of Earth and Planetary Sciences, McGill University, Montreal, Quebec H3A 2A7, Canada; and Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina 29802
منابع مشابه
Records of an ancient Martian magnetic ¢eld in ALH84001
Although Mars does not presently appear to have a global dynamo magnetic field, strong crustal fields have recently been detected by the Mars Global Surveyor above surfaces formed V3 or more Ga. We present magnetic and textural studies of Martian meteorite ALH84001 demonstrating that 4 Ga carbonates containing magnetite and pyrrhotite carry a stable natural remanent magnetization. Because 40Ar/...
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ALH84001 is the only martian meteorite currently known with a crystallization age of 4.5 Ga. This ancient age indicates the meteorite must come from the ancient crust of Mars, located primarily in the southern hemisphere of the planet. The 4.56 Ga crystallization age, the 16 Ma ejection, and theoretical models of how material is ejected off Mars were used to identify possible source craters for...
متن کاملMagnetic tests for magnetosome chains in Martian meteorite ALH84001.
Transmission electron microscopy studies have been used to argue that magnetite crystals in carbonate from Martian meteorite ALH84001 have a composition and morphology indistinguishable from that of magnetotactic bacteria. It has even been claimed from scanning electron microscopy imaging that some ALH84001 magnetite crystals are aligned in chains. Alignment of magnetosomes in chains is perhaps...
متن کاملTemperatures on Mars from 40Ar/39Ar thermochronology of ALH84001
The thermal history of Martian meteorite ALH84001 has critical implications for its petrological and deformational history, the age of its trapped atmospheric gases, the timing of the Martian dynamo, and possibly the evolution of Martian surface temperatures during the last 4 billion years (Gyr). Feldspathic glass in ALH84001 has been dated using 40K/40Ar and 40Ar/39Ar chronometry by several la...
متن کاملMagnetite biomineralization and ancient life on Mars.
Certain chemical and mineral features of the Martian meteorite ALH84001 were reported in 1996 to be probable evidence of ancient life on Mars. In spite of new observations and interpretations, the question of ancient life on Mars remains unresolved. Putative biogenic, nanometer magnetite has now become a leading focus in the debate.
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ورودعنوان ژورنال:
- Applied and environmental microbiology
دوره 68 8 شماره
صفحات -
تاریخ انتشار 2002