Trace Element, Ni, PGE and Au Geochemistry of Sivas - Kızıldağ Ophiolites (Central Anatolia) (In Turkish with english Abstract): Yahya ÇİFTÇİ (original) (raw)

Abstract The Kızıldağ (Sivas) Ophiolites, belonging to the Refahiye Ophiolitic Melange, generaly consist of wherlite of transition zone, gabbros of mafic cumulate sequence and pyroxene gabbros, hornblende gabbros, microgabro intrutions, meta basalts and spilitic basalts. The ophiolitic complex is cut by Neogene magmatics, represented by aplite veins, granite, quartz monzonite and diorite as well as volcanic products such as andesite and basalt. Ni enrichment, up to 4630 ppm took place within the ophiolite bodies. Ore microscopy studies have revealed that the source of Ni is linneit, bravogite, gersdorfite, millerite, heazlewoodite and pentlandit e minerals. This study reveals that Ni, occurring at levels of 0.2 to 0.3 % in primary ultramafic rocks, shows enrichments up to 0.46 %. It is belived here that with more detailed studies, economical nickel deposits may be found. The ultramafic rocks in the investigation area show variable contents of Pt group elements comparition with primitive mantle values. Os and Ru show enrichment, Ir, Rh and Pt show depletion, Pd shows both effects but with few changes. Au, which is treated geochemicaly with Pt group elements, shows enrichment relatieve to primitive mantle values with few amounts. Comparision of Kizildag Ophiolites with N-Type MORE, the normalized values of REE's show generaly depletion except U and Ta. The Cl Chondrite normalized values of REE's show different pattern; Th, U, Ta, La and Ce show enrichment up to 10 times but Sr, Nd, Zr, Sm, Tb, Y, Yb, Rb and Ba show depletion with different amounts. Keywords: Sivas - Kizildag Ophiolites, Nr- PGE - Au Geochemistry