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Record Details

Record 5 of 1809
Post-eruptive alteration of silicic ignimbrites and lavas, Gran Canaria, Canary Islands - Strontium, neodymium, lead, and oxygen isotopic evidence
External Online Source: doi:10.1016/0016-7037(93)90374-6
Author and Affiliation:
Cousens, Brian L.(Montreal Univ., Canada)
Spera, Frank J.(California Univ., Santa Barbara, United States)
Dobson, Patrick F.(Unocal Corp., Brea, CA, United States)
Abstract: The 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.
Publication Date: Feb 01, 1993
Document ID:
19930041851
(Acquired Dec 28, 1995)
Accession Number: 93A25848
Subject Category: GEOPHYSICS
Document Type: Journal Article
Publication Information: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 57; 3; p. 631-640.
Publisher Information: United States
Contract/Grant/Task Num: NSF EAR-88-17200; NSF OCE-88-12078; NAGW-1452
Financial Sponsor: NASA; United States
Organization Source: NASA; Washington, DC, United States
Description: 10p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: CANARY ISLANDS; GEOCHEMISTRY; IGNEOUS ROCKS; LAVA; LEAD ISOTOPES; MAGMA; NEODYMIUM ISOTOPES; OXYGEN ISOTOPES; STRONTIUM ISOTOPES
Imprint And Other Notes: Geochimica et Cosmochimica Acta vol. 57, no. 3 p. 631-640. Feb. 1993
Miscellaneous Notes: Research supported by NSERC, GSA Penrose Grant, and Sigma Xi
Availability Source: Other Sources
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