NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Post-eruptive alteration of silicic ignimbrites and lavas, Gran Canaria, Canary Islands - Strontium, neodymium, lead, and oxygen isotopic evidenceThe isotopic composition of lavas from oceanic islands provides important information about the composition and evolution of the earth's mantle. Isotopic analyses of Miocene comenditic, pantelleritic, and trachyphonolitic ignimbrites and lavas from the Canary islands were performed. Results provide evidence for posteruptive mobility of Rb and Sr during low temperature postemplacement interaction with circulating ground water. Calculated Sr isotope ratios define a magmatic trend in the stratigraph section. 87Sr/86Sr ratios in hydrated vitrophyte and devitrified matrix separates indicate significant posteruptive interaction with meteoric water starting soon after deposition. This process extends patchily through the entire pyroclastic flow and may be ongoing. 87Sr/86Sr ratios determined by whole rock analysis of silicic rocks from oceanic islands are suspect and should not be incorporated into mantle tracer studies. Anorthoclase phenocrysts are resistant to these processes and may produce useful data.
Document ID
19930041851
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Cousens, Brian L.
(Montreal Univ. Canada)
Spera, Frank J.
(California Univ. Santa Barbara, United States)
Dobson, Patrick F.
(Unocal Corp. Brea, CA, United States)
Date Acquired
August 16, 2013
Publication Date
February 1, 1993
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 57
Issue: 3
ISSN: 0016-7037
Subject Category
Geophysics
Accession Number
93A25848
Funding Number(s)
CONTRACT_GRANT: NAGW-1452
CONTRACT_GRANT: NSF EAR-88-17200
CONTRACT_GRANT: NSF OCE-88-12078
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available