40Ar-39Ar Studies on Some Tanzawa Tonalite Samples.
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چکیده
منابع مشابه
Temperatures 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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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...
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Petrographically and chemically well-characterized rocks of the Apollo 14 landing site (12 impact melt breccias, 3 clast-free impact melt rocks, 2 granulitic rocks, 1 cataclastic noritic anorthosite, 1 shocked gabbronorite, 1 mare basalt, and 1 plagioclase single crystal) have been dated by the 40Ar-39Ar technique. The samples represent two different formations at the Apollo 14 site: (1) small ...
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The Erongo subvolcanic center in Namibia is the largest composite, bimodal complex in the Mesozoic Etendeka igneous province of Namibia. This study of 40Ar/39Ar and high spatial resolution U^Pb zircon dating demonstrates that emplacement of the various igneous units at Erongo took place within a time span equivalent to or shorter than geochronologically resolvable age differences (ca. 2 Ma), an...
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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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ژورنال
عنوان ژورنال: Journal of geomagnetism and geoelectricity
سال: 1993
ISSN: 0022-1392
DOI: 10.5636/jgg.45.261