Geochemical evidence for the genesis and eruptive setting of lavas from Tethyan ophiolites

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Authors:Pearce, J. A.
Volume Title:Ophiolites; Proceedings, International ophiolite symposium
Volume Authors:Panayiotou, A., editor
Source:p.261-272; Ophiolites; International ophiolite symposium, Nicosia, Cyprus, April 1-8, 1979, edited by A. Panayiotou. Publisher: Cyprus, Minist. Agric. Nat. Resour., Geol. Surv. Dep., Nicosia, Cyprus
Publication Date:1980
Note:In English. 45 refs.; illus. incl. 1 table
Summary:Most Tethyan ophiolites in the Mediterranean region fall into two categories: 1) fragmentary sequences of Late Triassic to Early Cretaceous age, and 2) fully developed complexes, probably of Late Cretaceous age. Lavas of the first category (Calabria, Apennines, Eastern Alps and Greece) are characterized by 'immobile' trace-element ratios, such as Zr/Y, Nb/Zr and Ce/Yb, which vary from slightly lower to significantly greater than chondritic values. Lavas with these characteristics are usually associated with 'anomalous' areas of oceanic crust. By contrast, lavas of the second category (Troodos, Semail) exhibit Zr/Y ratios significantly lower than chondritic. Lavas with these characteristics have virtually never been recovered from major oceans. Ophiolites of the first category can be related to mantle depleted in incompatible elements and then enriched in the same elements by migrating fluids or interstitial melts in a 'within-plate' setting, whereas those of the second category can be related to mantle first depleted in incompatible elements but then enriched by aqueous fluids and hydrophilic elements driven off subducted oceanic lithosphere in an arc-basin setting. [R.A.H.]
Subjects:Alteration; Composition; Cretaceous; Genesis; Geochemistry; Igneous rocks; Lava; Mesozoic; Ophiolite; Petrology; Physical models; Plutonic rocks; Tectonics; Tethys; Triassic; Ultramafics; Mediterranean region
Abstract Numbers:84M/2092
Record ID:1981057981
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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