Sulphur presence in paleokarst infillings and bitumen signs in upper cretaceous carbonates from the Kruja zone (Albania)

Kruja zone represents mainly shallow-water carbonate deposits (Cr2-Pg2). They consist of dolomites, limestones with rudists also rich in miliolides and textularides with frequent hiatus, emersions, discontinuity surfaces and even bauxitic horizons. This paper aid to provide some explanations about the origin of blue clays within paleokarst infillings, caverns and the presence of bitumen and their impact in the surrounding rocks in the region of Burizana in Makareshi anticline structure, Kruja zone. This area was previously known for oil exploration and several exploration wells were drilled, in the South-East, as Makareshi-1 well, while in the West, Ishem, a series of wells, all with the object of oil exploration in carbonate section from the surrounding structures. Also, in this region, the presence of Miocene transgression is present. The presence of terrigenous rocks in the highest hypsometric position, the intrusion of blue-grey clays between carbonate formation, the smell of sulphur in the blue clay formation and the bitumen signs in the cavities of the carbonate rocks are part of the present study.