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High-frequency sea-level changes recorded within the deep water carbonates of the Upper Cretaceus Dol Formation (Island of Brač, Croatia)

The upper part of the Middle–Coniacian/Santonian–Middle Campanian deep-water Dol Formation of the Island of Brač is composed of countless fine-grained allodapic intercalations deposited in an intraplatform trough. Within the studied section 13 beds can be distinguished, each defined by its lower part built up of dark grey limestone with abundance of branched, horizontally to subhorizontally oriented burrows, and the upper part, in which the light grey to white limestone contains larger burrows, rarely branched, showing no preferential orientation. The lower, dark grey, intensively bioturbated levels are interpreted as intervals formed during high-frequency sea-level highstands, while the upper, light grey-to-white levels are interpreted as intervals formed during the high-frequency sea-level lowstands. Cyclic alternation of these two intervals within the fine-grained allodapic beds is interpreted as the interaction between the amount of carbonate production on the platform margin and the periodicity and intensity of shedding and deposition in the distal part of toe-of-slope environment, which is governed by Milankovitch-band high frequency sea-level changes.

Campanian; Croatia; Adriatic-Dinaric carbonate platform; Dol Formation; carbonate sedimentology; high-frequency sea-level changes; intraplatform trough

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