40Ar-39Ar chronology of lunar meteorites Northwest Africa 032 and 773
نویسندگان
چکیده
منابع مشابه
Refining lunar impact chronology through high spatial resolution 40Ar/39Ar dating of impact melts
Quantitative constraints on the ages of melt-forming impact events on the Moon are based primarily on isotope geochronology of returned samples. However, interpreting the results of such studies can often be difficult because the provenance region of any sample returned from the lunar surface may have experienced multiple impact events over the course of billions of years of bombardment. We ill...
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Introduction: Only 5 meteorites were classified into unbrecciated lunar mare basalt so far, although there are about 40 lunar meteorites known to date. NWA 032 and its paired meteorite NWA 479 (NWA) are such crystalline mare basalts, and show a porphy-ritic texture composed of euhedral olivine and pyrox-ene grains with dendritic mesostasis of pyroxene, pla-gioclase and accessory minerals (ilmen...
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Introduction: Crystallization of the lunar magma ocean occurred ~4.4 Ga [e.g., 1-4] and produced three principal magma source regions [5-6]. These sources are characterized chemically by low titanium (Ti), high Ti, and high potassium, rare earth element, and phosphorous (KREEP) abundances. The KREEP component was produced after nearly complete solidification of the magma ocean and is highly enr...
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The deposits of Eocene Lake Gosiute that constitute the Green River Formation of Wyoming contain numerous tuff beds that represent isochronous, correlatable stratigraphic markers. Tuff beds selected for 40Ar/39Ar analysis occur within laminated mudstone, are matrix supported, and lack evidence of reworking. These tuffs contain 2%–15% euhedral phenocrysts of quartz, plagioclase, sanidine, biotit...
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...
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ژورنال
عنوان ژورنال: Meteoritics & Planetary Science
سال: 2003
ISSN: 1086-9379,1945-5100
DOI: 10.1111/j.1945-5100.2003.tb00026.x