Open AccessComposition and alteration of Cr-spinels from Milia and Pefki serpentinized mantle peridotites (Pindos Ophiolite Complex, Greece)
Author(s) -
Argyrios Kapsiotis
Publication year - 2014
Publication title -
geologica carpathica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.702
H-Index - 40
eISSN - 1336-8052
pISSN - 1335-0552
DOI - 10.2478/geoca-2013-0006
Subject(s) - ophiolite , peridotite , spinel , geology , geochemistry , chromite , mantle (geology) , olivine , metamorphic rock , mineralogy , tectonics , paleontology
The Pindos Ophiolite rocks include variably serpentinized peridotites derived from a harzburgitic and subordinately dunitic mantle. In the serpentinized matrix of these rocks pseudomorphic (mesh, bastite) and non-pseudomorphic (interpenetrating, type-2 hourglass) textures were recognized. Chromian spinel (Cr-spinel) is anhedral to subhedral and often replaced by a porous opaque phase. Chemistry data show that Cr-spinel cores retain their original composition, having Cr#[Cr/(Cr + Al)] that ranges between 0.45 and 0.73, and Mg#[Mg/(Mg + Fe2+)] that varies between 0.52 and 0.65, accompanied by low content in TiO2 ( 300 °C). The limited occurrence of ferrian chromite with high Fe3+# values suggests that elevated oxidizing conditions were prevalent only on a local scale during Cr-spinel alteration