Annealing of shocked quartz during atmospheric re-entry

被引:11
作者
Croskell, M [1 ]
Warner, M [1 ]
Morgan, J [1 ]
机构
[1] Univ London Imperial Coll Sci & Technol, Dept Earth Sci & Engn, Royal Sch Mines, London SW7 2BP, England
关键词
D O I
10.1029/2001GL014382
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
The Chicxulub impact launched shocked quartz grains on ballistic trajectories outside the atmosphere, thus enabling their global dissemination. The shocked grains heated up during atmospheric re-entry and the maximum temperature reached was related to their size, velocity and re-entry angle. The extreme heating of some shocked quartz grains is likely to have resulted in the destruction of their planar deformation features (PDFs). A significant negative correlation exists between the palaeodistance from Chicxulub of a given K/T boundary locality and the size of the largest shocked quartz crystal found at that locality. The re-entry annealing process can explain this correlation. The largest shocked quartz grain at a given locality followed the shallowest available trajectory and survived re-entry without being thermally annealed. Larger crystals and those on steeper trajectories exceeded the annealing point and lost their PDFs.
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页数:4
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