Characteristics of the amphibolites from Nigde metamorphics (Central Turkey), deduced from whole rock and mineral chemistry
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Date
2007
Journal Title
Journal ISSN
Volume Title
Publisher
GEOCHEMICAL SOC JAPAN
Access Rights
info:eu-repo/semantics/openAccess
Abstract
Whole rock and mineral chemistry of amphibolites are presented for the lower (Gumusler Formation) and higher parts (Kaleboynu Formation) of the Nigde Massif with the aim to constrain protolith genesis and metamorphic P-T-conditions. The amphibolites, associated with a series of supracrustal metasediments, as thin layers and discontinuous pod/small lenses, are of igneous origin with composition of subalkaline and tholefitic basalts. Based on immobile elements content and ratios, amphibolites from both formations are thought to have formed mostly by fractional crystallisation of pyroxene +/- spinel, amphibole, plagioclase as well as apatite and titanite; coupled with minor crustal contamination. Contamination is particularly clear for the Gumusler Formation formed in a back-arc basin (Paleothetys) during magmatic ascent through the thickened Central Anatolian crust. The basic rocks could have been metamorphosed later at 7.5-3 +/- 0.6 kb and 850-420 degrees C, with the temperature gradient ranging from 35 to 122 degrees C/km at different depths in the Neo-Tethyan subduction zone, and exhumed from depths of approximately 20 km via regional extension.
Description
Keywords
amphibolites, metamorphism, MORB magmas, Nigde massif, geochemistry
Journal or Series
GEOCHEMICAL JOURNAL
WoS Q Value
Q4
Scopus Q Value
Q3
Volume
41
Issue
4
