Highly Siderophile Element and Os Isotope Systematics of Volcanic Rocks at Divergent and Convergent Plate Boundaries and in Intraplate Settings

Abdelmouhcine Gannoun, Kevin W. Burton, James Day, Jason Harvey, Pierre Schiano, Ian J Parkinson

Research output: Chapter in Book/Report/Conference proceedingChapter in a book

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Abstract

Terrestrial magmatism is dominated by basaltic compositions. This definition encompasses mid-ocean ridge basalts (MORB), which account for more than eighty percent of Earth’s volcanic products and which are formed at divergent oceanic plate margins, as well as intraplate volcanic rocks such as ocean island basalts (OIB), continental flood basalts (CFB) and continental rift-related basalts, and highly magnesian ultramafic volcanic rocks that dominantly occur in Archean terranes, termed komatiites. All of these broadly basaltic rocks are considered to form by partial melting of the upper mantle, followed by extraction from their source regions and emplacement at the Earth’s surface. For these reasons, basalts can be used to examine the nature and extent of partial melting in the mantle, the compositions of mantle sources, and the interactions between the crust and mantle. Because much of Earth’s mantle is inaccessible, basalts offer some of the best ‘proxies’ for examining mantle composition, mantle convection and crust–mantle interactions. By contrast, at arcs, volcanism is dominated by andesitic rock compositions. While some arcs do have basaltic and picritic magmatism, these magma types are rare in convergent plate margin settings and reflect the complex fractional crystallization and often associated concomitant assimilation processes occurring in arcs. Despite the limited occurrence of high MgO magmas in arc volcanic rocks, magmas from this tectonic setting are also important for elucidating the behavior of the HSE from creation of basaltic compositions at mid-ocean ridges to the subduction of this crust beneath arcs at convergent plate margins.
Original languageEnglish
Title of host publicationHighly Siderophile and Strongly Chalcophile Elements in High-Temperature Geochemistry and Cosmochemistry
PublisherMineralogical Society of Great Britain
Pages651-724
Number of pages74
ISBN (Print)9780939950973, 0939950979
DOIs
Publication statusPublished - Jan 2016

Publication series

NameReviews in Mineralogy and Geochemistry
PublisherMineralogical Society of Great Britain
Number1
Volume81
ISSN (Print)1529-6466

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