Osmium isotopes in ophiolites

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doi: 10.1016/0012-821X(91)90086-W
Authors:Luck, Jean-Marc; Allègre, Claude J.
Author Affiliations:Primary:
Inst. Phys. Globe, Lab. Géochim. et Cosmochim., Paris, France
Volume Title:Earth and Planetary Science Letters
Source:Earth and Planetary Science Letters, 107(2), p.406-415. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X
Publication Date:1991
Note:In English. Inst. Phys. Globe Paris, Contrib. No. 1188. 68 refs.; illus. incl. 1 table
Summary:Re and Os concentrations and Os isotopic compositions are reported for ultramafic samples from ophiolites. The data can be divided into two groups: isotopic values > mean upper mantle (187Os/186Os = 1.05) which correspond with back-arc type ophiolites and could reflect injection of crustal material (sediments); and ophiolites referred to as being typical N-MORB which plot very close to previous estimates for mean upper mantle (1.05). Together with refined osmiridium results from well-dated ultramafic suites, the data on ophiolites lead to the following constraints: 1) present-day 187Os/186Os for the upper mantle seems for the moment constrained at approx 1.05-1.06, and 2) the mantle evolution curve for Os isotopes through time, when associated with recent Os isotopic determinations from the literature for Archaean samples, shows a 'chondritic' 187Re/186Os ratio of 3.33 and a linear, closed-system evolution. [R.E.S.]
Subjects:Back-arc basins; Basins; Geochemistry; Igneous rocks; Isotopes; Mantle; Metals; Ophiolite; Os-187/Os-186; Osmium; Platinum group; Plutonic rocks; Radioactive isotopes; Rhenium; Stable isotopes; Trace elements; Ultramafics; Upper mantle; Re-187/Os-186
Abstract Numbers:92M/2993
Record ID:1992005177
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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