İsmail Cihan Abstracts

Ulutaş (Erzurum-Turkey) Cu-Mo Deposit


İsmail Cihan

Demir Export, Ankara, Turkey



The Ulutaş Cu–Mo prospect lies within the Ispir batholith Based on drill-hole data, the total reserves were estimated at 73.6 Mtat a grade of 0.31% Cu and 0.022% Mo (Giles, 1973; Soylu, 1999; Yiğit,2009).Porphyry type Cu–Mo mineralization at the Ulutaş prospect is hosted by granite porphyry and quartz porphyry of the Ispir batholith,which is a calc-alkaline multi-phase plutonic complex varying from granite through quartz diorite to syeno-diorite. The oldest units exposed in the northwestern part of the Ulutaş areaare Paleozoic–Lower Mesozoic metamorphic rocks. The metamorphic basement is covered by strongly folded, weakly metamorphosed Cretaceous lava flows of dacitic to rhyolitic composition and pyroclastic rocks with intercalations of laminated mudstone, and shale (Giles, 1973;Taylor and Fryer, 1980). The basement units and volcano-sedimentary sequence are intruded by Ulutaş intrusions that form an erosion window in the Eocene units, comprising andesitic to basaltic lava, tuff andagglomerate with marl, conglomerate, sandstone and limestone intercalations(Giles, 1973; Taylor and Fryer, 1980). A granite porphyry hosting Cu–Mo mineralization exposed in the northern part of the area represents the largest intrusive unit in theregion. It is characterized by a pronounced porphyritic texture at the outcrop scale. Central parts of the granite porphyry are characterized by intrusions of NE-trending, steeply dipping quartz porphyry dykes or stocks, with a porphyritic texture with phenocrysts of embayed quartz and a fine-grained groundmass of quartz and highly sericitized plagioclase. Both granite porphyry and quartz porphyry are crosscut by dioritic, andesitic dykes hosting pyrite–chalcopyrite veinlets (1 to2 mm), The granite porphyry contains micro-granular, roughly oval medium to dark gray dioritic enclaves, which have sharp contacts with their host. All units are overlain by Pleistocene to recent glacial debris and alluvial sediments (Giles, 1973).Porphyry-type mineralization in the Ulutaş area consists of stock work veins and NW-striking quartz veins,with disseminated chalcopyrite ealong the vein systems, and molybdenite within the 1–2 cmt hick quartz veins (Soylu, 1999).