کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4678762 | 1634862 | 2009 | 5 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: High-pressure phases in an ultramafic rock from Mars High-pressure phases in an ultramafic rock from Mars](/preview/png/4678762.png)
Shock-induced melt pockets in the martian meteorite Chassigny are completely transformed into a set of high-pressure mineral phases previously unknown from ultramafic rocks, the major constituents of the Earth's mantle. Ferropericlase, amorphous (Mg,Fe)SiO3-perovskite, ringwoodite, wadsleyite, high-pressure phosphate γ-Ca3(PO4)2, and CaTi2O4-structured chromite were formed by solid state transformation and fractional crystallization upon pressure release from > 23 to 10 GPa. During shock pressure release the temperatures in the melt pocket dropped to timescales of 10− 2 to 10− 3 s to allow preservation of the high-pressure phases. Formation and preservation of these phases in Chassigny depend on the duration of shock compression, which increases with the pre-impact burial depth of the meteorite below the martian surface. The estimated burial depth of 25 to 250 m is in agreement with the sampling depth of potential source craters for the Chassigny meteorite.
Journal: Earth and Planetary Science Letters - Volume 288, Issues 3–4, 15 November 2009, Pages 619–623