Geochemical comparison of ultramafic-mafic cumulate rocks from the Central Anatolian ophiolites, Turkey

Ophiolites, formed during closure of the Neo-Tethyan ocean, are widespread in Turkey and have been extensively studied. In addition to ophiolites showing recognizable stratigraphic sequences, numerous massive and layered gabbroic masses occur as isolated outcrops in the Central Anatolian Crystalline Complex. An example from the Akeakent region ranges from gabbro to diorite; another, from the Kustepe area, is characterized by dunite, wehrlite, troctolite, olivine gabbro, clinopyroxene gabbro, clinoproxene hornablende gabbro, uralite gabbro, and fine-grained gabbro. Samples from bothe regions desplay adcumulate and orthocumulate textures and show low-K and subalkaline characters; they are enriched in some LILE (e.g. Sr, Rb, K, Ba) and depleted in HFSE (e.g., Ta, Nb, Zr, Ti) relative to N-MORB. Petrological data, negative Ta, Nb, Zr, Ti anomalies, and ratios of elements such as Ba/Nb and La/Nb indicate a suprasubduction setting for the central Anatolian ultramafic-mafic rocks, suggesting that both rock types may have formed in a backare setting.