Trace element and strontium isotope characteristics of volcanic rocks from Isla Tortuga: A young seamount in the Gulf of California

Earth and Planetary Science Letters
By: , and 

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Abstract

Isla Tortuga is a small isolated central volcano which is located near an actively spreading trough in the Gulf of California. The basalt lavas from Tortuga which have the highest Mg/Fe and Ni contents have trace element abundances and ratios and87Sr/86Sr which are similar to those of mid-ocean ridge tholeiite. The major element, rare earth element and Sr abundances of fractionated tholeiite (low Mg/Fe) and tholeiitic andesite of Tortuga are consistent with an origin by closed-system fractional crystallization. This hypothesis is not supported by K, Na, Rb and Ba abundances in the lavas nor by their variable87Sr/86Sr (0.7024–0.7035). It is proposed that the apparent decoupling of light rare earth elements, other incompatible trace elements and87Sr/86Sr is due to contamination of some Tortuga magmas while they are fractionated in a high-level crustal magma chamber. The mantle source of least-contaminated, high Mg/Fe basalt lavas of Tortuga is similar, although not identical to the source of normal mid-ocean ridge tholeiite; significant differences exist. The reasons for these differences are not yet known.

    Publication type Article
    Publication Subtype Journal Article
    Title Trace element and strontium isotope characteristics of volcanic rocks from Isla Tortuga: A young seamount in the Gulf of California
    Series title Earth and Planetary Science Letters
    DOI 10.1016/0012-821X(79)90211-5
    Volume 43
    Issue 2
    Year Published 1979
    Language English
    Publisher Elsevier
    Description 10 p.
    First page 269
    Last page 278
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