30255
Accession Number
6131
Author
Mead, Cynthia W.; Littler, Janet; Chao, E.C.T.
Author Affiliation
U.S. Geological Survey;U.S. Geological Survey;U.S. Geological Survey
Title Of Article Chaper
Metallic Spheroids from Meteor Crater, Arizona
Title Of Journal Book
American mineralogist
Volume
50
Pages
667-681
Reference Bibliography
Includes bibliographical references
Language Of Text
English
Literature Type
Serial
Literature Level
Analytic
Abstract
The mineralogy, texture and chemical compositions of metallic spheroids from Meteor Crater, Arizona, were studied in detail. The spheroidal to elongate particles studied average 0.5 mm across and characteristicaily are coated by siliceous glass containing numerous minute fragments of quartz. Some spheroids consist of a fine-grained granular kamacite core, commonly intergrown and surrounded by a goethite iron oxide and maghemite. Associated with the kamacite is an interstitial pink mineral optically similar to the pink schreibersite inclusions in the metallic spherules in philippinites and indochinites. X-ray powder patterns of this pink mineral from the Meteor Crater spheroids are also identical to that of shreibersite. Electron microprobe analysis shows: Kamacite (has) 2-24per thousand Nickle (and) 74-97per thousand Iron; Maghemite (has) 5-6per thousand Nickel (and) 59-62per thousand Iron; (and the) Goethite-like mineral (has) 2-14per thousand Nickel (and) 45-60per thousand Iron. The wide range of nickel content in kamacite, the fine-grained texture and the siliceous glass coating of the spheroids indicate that the Meteor Crater spheroids probably condensed from a vapor or melt produced during impact of the meteorite. The range in Nickel content in the Kamacite of the Philippine and Indochina tektite spherules is nearly identical to that of the kamacite in the spheroids from Meteor Crater, whose meteoric origin is certain.
pub_id
30255
Issue Date
19650000 May-June,