Co-existent cristobalite and iridium at 65 Ma, Anjar Intertrappeans, Kachchh, western India

Cristobalite (a high-temperature low-pressure silica polymorph) is reported for the first time from the 65 Ma Anjar intertrappean deposits. It is characterized by a sharp, intense peak (X-ray diffraction) at d-spacing value 4.055Angstrom, followed by a moderate peak at 2.489Angstrom. Its presence is...

Full description

Bibliographic Details
Published in:Cretaceous Research
Main Authors: SANT, DA, MATHEW, G, KHADKIKAR, AS, GOGTE, V, GUNDURAO, TK
Format: Article in Journal/Newspaper
Language:English
Published: ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD 2003
Subjects:
Cretaceous-Tertiary Boundary
Deccan Volcanism
Extinction
Sediments
Province
Iceland
Events
Ocean
Traps
Area
K/T
Deccan
Anjar
Cristobalite
Mineralogy
Meteorite
Iridium
Online Access:http://dspace.library.iitb.ac.in/xmlui/handle/10054/3568
https://doi.org/10.1016/S0195-6671(03)00028-4
http://hdl.handle.net/10054/3568
Description
Summary:Cristobalite (a high-temperature low-pressure silica polymorph) is reported for the first time from the 65 Ma Anjar intertrappean deposits. It is characterized by a sharp, intense peak (X-ray diffraction) at d-spacing value 4.055Angstrom, followed by a moderate peak at 2.489Angstrom. Its presence is confirmed through Fourier Transform Infrared spectroscopy with absorption bands at 620 and 380 cm(-1). The distribution of volcanic cristobalite coincides with the distribution of iridium in the deposits. When taken in tandem with the absence of shocked quartz, spinels, stishovite and other signatures of an impact origin, this co-existence suggests that the iridium at Anjar is probably of volcanic origin. (C) 2003 Elsevier Ltd.

Similar Items