DISCUSSION ON THE ORIGIN OF OTLUKİLİSE IRON DEPOSIT GÜRÜN-SİVAS

Abstract

In this study, the geological aspects of Otlukilise iron deposit near Gürün (Sivas, Turkey) is investigated and possible mechanicms responsible for the formation of that deposit are discussed. Otlukilise iron occurrences are located in volcanosedimentary levels in Yanıktepe and Akdere formations which are age of Upper Cretaceous and Paleocene, respectively. The occurrence of Otlukilise iron formations is belived to have taken place as enrichments by secondary processes from siderite ores volcanosedimentary origin in relation with volcanic intercalations. Studies carried out on iron rich massive ores indicate an old formation in a sedimentary basin that represented by cumulative supplements of iron and associated elements which are directly on indirectly leached from serpentinites by submarine volcanites spreading out into an environment of carbonate deposition and hydrothermal exhalative fluxes and associated silicate phases formed by intensive silica rich fluids of hydrothermal origin and sulphide phases resulted from reactions of seewater and the same submarine volcanites. Sequential conjugateness observed especially among quartz and siderite, clay and/or clay bearing siderite layers in iron poor conglomerate breccia ore samples and estimations realized by certain mathematical rules indicate a sedimentary relationship prior to deformation. Both massive ores and fragments are deposited by the processes during formation of an ore horizon intercalated by clay and quartz rich levels and/or just after the movements at the bottom of the basin. Thus, Otlukilise iron deposits represent an other sample of Lahn-Dill type syn-sedimentary volcanogenic or exhalative-sedimentary type ore formation as Deveci Iron Deposits (Hekimhan-Malatya, Turkey) do.