Genesis of Bauxite Bearing Iron Ore Deposits From Payas (Hatay) District

Abstract

In the study area, a unit composed of dolomite and dolomilic limestone of Lower Triassic-Lower Jurassic age forms the base. This unit up to 400 m. thick is conformably overlain by Lower Cretaceous units represented by limestone and dolomilized limestone. These limestones which also host mineralization arc conformably overlain by Senonian olisloslromal sequence. A sequence consisting of conglomerate, sandstone and limestone, that is of Middle Miocene age conformably overlies the olisloslromal fades. The Upper Pliocene sediments occurring over extensive flatnes areas rest conformably upon all of the units in the study area. Mineralization in the region occurs as lenses between the Lower Crelaccous limestones and Senonian limestones. Ore bodies lie on lop of limestones characterized by common dissolution cavities and brecciated in places and on top of sandstones in other places. Ore microscopic studies reveal that main ore minerals arc maghemite, hematite and goethile. Mineral paragenesis also includes berthierine, diaspore, quartz and calcile. Massive, granular, colloidal and oolitic textures are observed in ores. On the basis of sedimentary petrographic studies, three types of mineralization in which massive, granular and combined massive and granular textures arc dominant could be recognized. Each type is characterized by dissolution cavities and microkarstification features. Geologic, ore microscopic and sedimentary petrographic studies provide evidence that these deposits have originally developed on top of a gentle topography by long-lived atmospheric effects and subsequently washed away and broken up and eventually formed by infilling of regional karstic cavities by transported material.