The Development of the Eocene Platform Carbonates from Wells in the Middle Adriatic Off-Shore Area, Croatia

Abstract

In the Middle Adriatic deep off-shore wells the following sedimentaryfaciess exist: fenestral and Charophyte limestone facies (X); facies of foraminiferal wackestone-packstone, ostracod marls and fine grained breccia conglomerate (A): facies of foraminiferal packstonegrainstone (B) and miliolidal mudstone-wackestone (C): facies of porous limestone?, grainstone? (Y): facies of fossiliferous mudstonepackstone (D); algal bound stone/bindstone and wackestone facies (E): facies of the foraminiferal mudstone-packstone (F); Nummulites - Discocyclina floatstone-packstone and grainstone-rudstone facies (G). The sediments were deposited close to the carbonate platform margin. Beds of facies X have an uncertain stratigraphic position; younger than the Cretaceous but older than the Cuisian. A transgressive sequence that is composed of facies A, B, C and Y was formed during the Cuisian, whereas the others belong to Lutetian (and Biarritzian). At the end of the Middle Eocene they were tectonically compressed and covered by flysch deposits. Good stratigraphic correlation between the wells along the Dinaric strike strongly suggests that the facics are laterally extensive in this direction. Perpendicular to the trend they arc considerably reduced. Oil shows in the Kate- I well originated from the Lower Cretaceous so surce rocks (evaporite complex).