Shock Metamorphism of Martian Meteorites: New Data from Quantitative Shock
نویسندگان
چکیده
Introduction: The Martian origin of the group of SNCOs comprising now 16 different meteorites is widely accepted [1]. The ejection of these meteorites from Mars requires an impact process which necessarily involves a certain level of shock metamorphism affecting the meteorites to get accelerated to Martian escape velocity. Previous studies [2 and ref. in 1] clearly showed that all 16 Martian meteorites are moderately to strongly shocked with the effect that in most meteorites plagioclase is transformed to diaplectic glass [3] except in the nakhlites. A first order estimate for all 16 samples shows that the range of observed shock pressures derived from shock effects in the constituent minerals is limited to about 15 to 45 GPa. It appears highly desirable to obtain quantitative shock barometry for all 16 meteorites which is so far only available for 4 of them. For 6 meteorites we present first results of a comprehensive shock barometry study which is based on high precision refractive index measurements of plagioclase and on experimental calibration of the refractive index by shock recovery experiments [2].
منابع مشابه
Timescales of Shock Processes and the Size of Martian Meteorites Source Craters, Constrained from Shock
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