Discussion
Presence of stishovite in a rock indicates :
Answer: D
Stishovite indicates the vicinity of a meteoric impact crater.
Stishovite is a very dense polymorph of SiO\(_{2}\) in which silicon is in six-fold coordination. It forms only at pressures above about 8-10 GPa, which are not reached in the Earth's crust. In nature it is found in rocks shocked by meteorite impacts, as at Meteor Crater, Arizona, where it was first found in nature in 1962.
Divergent boundaries, volcanic calderas and ordinary subduction-zone rocks at crustal levels do not reach such pressures, so stishovite at the surface is diagnostic of impact.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development