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Age and Sr isotopic composition of volcanic rocks in the Maricunga Belt, Chile: implications for magma sources

Journal of South American Earth Sciences

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, , , , and

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Abstract

K-Ar and 40Ar/39Ar dating of volcanic rocks from the Maricunga belt of north-central Chile indicate that igneous activity took place throughout most of Miocene time at various places in the 150 by 30 km belt. No migration patterns of volcanism appear in the Miocene rocks of the belt. Volcanic activity ceased by the end of the Miocene. All the Miocene volcanic rocks studied are calcic andesites to dacites with about 62% SiO2, 18% A12O3, 4% Fe2O3 (total), and 2% K2O. Initial 87Sr/86Sr (Sri) values fall into two groups, one of lower values around 0.7050 to the west and the other of higher values around 0.7060 to the east. It is postulated that the two Sri groups reflect two adjoining coherent lower-crustal magma sources of possibly different age and subtly different composition that form part of the western edge of the South American craton. ?? 1994.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Age and Sr isotopic composition of volcanic rocks in the Maricunga Belt, Chile: implications for magma sources
Series title:
Journal of South American Earth Sciences
Volume
7
Issue:
2
Year Published:
1994
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of South American Earth Sciences
First page:
167
Last page:
177