Coesite in suevites from the Chesapeake Bay impact structure

Meteoritics and Planetary Science
By: , and 

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Abstract

The occurrence of coesite in suevites from the Chesapeake Bay impact structure is confirmed within a variety of textural domains in situ by Raman spectroscopy for the first time and in mechanically separated grains by X-ray diffraction. Microtextures of coesite identified in situ investigated under transmitted light and by scanning electron microscope reveal coesite as micrometer-sized grains (1–3 μm) within amorphous silica of impact-melt clasts and as submicrometer-sized grains and polycrystalline aggregates within shocked quartz grains. Coesite-bearing quartz grains are present both idiomorphically with original grain margins intact and as highly strained grains that underwent shock-produced plastic deformation. Coesite commonly occurs in plastically deformed quartz grains within domains that appear brown (toasted) in transmitted light and rarely within quartz of spheroidal texture. The coesite likely developed by a mechanism of solid-state transformation from precursor quartz. Raman spectroscopy also showed a series of unidentified peaks associated with shocked quartz grains that likely represent unidentified silica phases, possibly including a moganite-like phase that has not previously been associated with coesite.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Coesite in suevites from the Chesapeake Bay impact structure
Series title Meteoritics and Planetary Science
DOI 10.1111/maps.12638
Volume 51
Issue 5
Year Published 2016
Language English
Publisher Wiley
Contributing office(s) Eastern Mineral and Environmental Resources Science Center
Description 20 p.
First page 946
Last page 965
Country United States
Other Geospatial Chesapeake Bay