Evolution of boninites and island-arc tholeiites in the Pindos Ophiolite, Greece

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doi: 10.1017/S0016756804009215
Authors:Pe-Piper, Georgia; Tsikouras, Basilios; Hatzipanagiotou, Konstantin
Author Affiliations:Primary:
Saint Mary's University, Department of Geology, Halifax, NS, Canada
Other:
University of Patras, Greece
Volume Title:Geological Magazine
Source:Geological Magazine, 141(4), p.455-469. Publisher: Cambridge University Press, London, United Kingdom. ISSN: 0016-7568
Publication Date:2004
Note:In English. Includes appendices. 43 refs.; illus., incl. 4 tables, geol. sketch map
Summary:Whole-rock geochemical and Sm/Nd isotope data are given for a suite of crustal rocks from the Pindos ophiolite in order to resolve the origin of the geochemical signature of the boninites. Comparison is made with Triassic MORB from the Avdella melange and other ophiolitic rocks of northwestern Greece. Hydrothermal alteration results in a large scatter of Sr and K and some variability in Ba, Th and U. The Pindos boninites contain high Zr and Hf with respect to REE, characteristic of many boninites. Pb, La/Sm and Nb decrease with decreasing TiO 2 from MORB to IAT, but then increase in the boninites. Nd isotopic values expressed as εNd decrease systematically with decreasing TiO2, from 7-8 in IAT to 0.6-3.0 in boninites. As mantle wedge harzburgite became increasingly depleted, another magma source contributed significant amounts of Pb, REE and probably Nb. The Pb and other large-ion lithophile elements may have been transported in aqueous solutions from the subducting slab, but the REE and Nb imply an ocean island basalt (OIB) source within the mantle wedge, a consequence of mantle plume activity during late Triassic rifting. [G.L.B.]
Sections:Geochemistry; Petrology
Subsections:Igneous rocks; Oceanic petrology
Subjects:Absolute age; Andesites; Ar/Ar; Basalts; Boninite; Chemical composition; Chemical ratios; Crust; Dates; Geochemistry; Igneous rocks; Island arcs; Isotope ratios; Isotopes; Jurassic; Major elements; Melange; Mesozoic; Metals; Mid-ocean ridge basalts; Neodymium; Oceanic crust; Ophiolite; Petrography; Plate tectonics; Plutonic rocks; Radioactive isotopes; Rare earths; Samarium; Sedimentary rocks; Sm-147/Nd-144; Spectra; Stable isotopes; Tholeiite; Trace elements; Volcanic rocks; X-ray fluorescence spectra; Europe; Greece; Pindus Mountains; Southern Europe; Avdella Melange; Pindos Ophiolite
Coordinates:N394500 N401500 E0212500 E0210000
Abstract Numbers:04M/3561
Record ID:2004084717
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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