Majid Ghasemi Siani; Behzad Mehrabi; Behrouz Karimi Shahraki
Abstract
The Ti-Fe Dar Gaz anomaly, is located in part of Kahnuj ophiolitic complex, S Iran, and consists of five major units; coarse-grained ferrogabbro to pyroxene-hornblende gabbro unit, ...
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The Ti-Fe Dar Gaz anomaly, is located in part of Kahnuj ophiolitic complex, S Iran, and consists of five major units; coarse-grained ferrogabbro to pyroxene-hornblende gabbro unit, fine-grained pyroxene-hornblende gabbro unit, fine-grained hornblende gabbro unit, feldspathic wehrlite unit and granitoieds. Sheeted diabasic, aplitic and plagiogranite dykes cross cut all the ultramafic-mafic major units. Mafic rocks are composed of pyroxene, plagioclase, hornblende, magnetite and ilmenite. Olivine and clinopyroxene occur as the main cumulus minerals in the ultramafic unit. Fe-Ti oxides occur as disseminated ores, intercumulus minerals and inclusions in silicate minerals. These rocks plot along the MgO-FeO* side in AFM diagram and associate with tholeiitic differentiation trend. The major element contents of the mafic rocks show narrow variations and located in the mafic cumulate, and show low-K series. REE-chondrite normalized patterns show that ultramafic rocks enriched in HREE rather than LREE, and with increase of hornblende modal in rocks, MREE and LREE increase, also. REE-chondrite and primitive mantle normalized patterns show that ultramafic and mafic rocks have a same parental magma with characteristics of mid-ocean ridge basalts.
