engleski

Upper Cenomanian–Lower Turonian Sequence Boundary On The Adriatic Carbonate Platform: An Example From The Korčula Island

The Adriatic Carbonate Platform (AdCP) is one of the largest Mesozoic carbonate platforms of the Perimediterranean region. Its predominately shallow water deposits comprise a major part of the entire carbonate succession of the Croatian Karst (External or Outer) Dinarides, which could be very thick, and ranges in age from the Middle Permian (or even Upper Carboniferous) to the Eocene (VLAHOVIĆ et al., 2005). During the Late Cretaceous, numerous sequences were deposited within shallow water depositional environments (HAQ, 2014). The Adriatic Carbonate Platform (AdCP) during the Late Cretaceous was characterized predominantly by shallow water sedimentation with few events marking beginning of sequences: two drownings of the platform (Cenomanian/Turonian and Santonian) and Campanian emergence (GUŠIĆ & JELASKA, 1990 ; MORO et al., 2002 ; VLAHOVIĆ et al., 2005). Besides typical shallow water environments with predominantly low-energy, protected paleoenvironments, mud-supported varieties of carbonates with elevator rudists, during Late Cenomanian more open paleoenvironment of relatively higher water energy also occur, characterized by predominantly grain-supported carbonates with recumbent ichthyosarcolitid and caprinid rudists. Their demise coincides with the Cenomanian–Turonian boundary (ROSS & SKELTON, 1993). At the Korčula Island succession of Cenomanian deposits is characterized by alternation of shallow-water peritidal laminated and non- laminated carbonates with thin layers of grainy carbonate variates and absence of typical drowned platform deposits. Although beginning of the Cenomanian/Turonian drowning coincides with OAE2 event (VLAHOVIĆ et al., 2005) characterized on global scale with the highest sea-level rise, that period was also characterized by very common relatively short- lasting third-order sequences, five of them within 3.7 Ma (HAQ, 2014). Moreover, during the Cenomanian the beginning of the AdCP demise was characterized by the occurrence of emerged areas in the NW part of the AdCP. Although above mentioned relatively dense presence of sequences around Cenomainan/Turonian boundary could be indicated by flodding of emerged areas more open, high energy paleoenvironments with recumbent rudists as well as drowned platform event with pelagic sedimentation as indication of the new sequence beginning, most probably influence of the local tectonics were the main controlling factor in their presence or absence in the southern part of the AdCP.

Upper Cretaceous, tectonics, Korčula Island, shallow-water carbonates

nije evidentirano