CYCLOSTRATIGRAPHY OF UPPER ALBIAN TROPICAL PLATFORM-INTERIOR CARBONATE FACIES, KORCULA ISLAND, SOUTHERN CROATIA

The Upper Albian succession of Korcula Island, southern Croatia, which is approximately 160 meters thick is represented by several carbonate facies indicative of tropical, shallow peritidal marine environments, and are arranged in shallowing upward parasequences. Facies from deep to shallow include (1) basal skeletal mudstones and wackestones (“deeper” subtidal) with microbial lumps and oncoids,; (2) peloid-skeletal wacke-packstones (shallow lagoon; rare); (3) Intraclast-peloid –skeletal packstones and grainstones (shallow-water sand flat); (4) barren lime mudstones (restricted lagoon); (5) laminites with crinkly, fenestral or flat laminae (tidal flat); and (6) intraclast rudstone – breccias (subaerial exposure). The lower 50 meters of the succession is dominated by parasequences of subtidal skeletal mudstone-wackestone and barren lime mudstone. Repeated thin subaerial breccia beds commonly cap parasequences in the middle part of the succession, likely indicating a sequence boundary zone. Laminite-capped parasequences increase in abundance up-section and in the upper part regressive laminites cap most of the parasequences. This likely indicates continued long term relative sea level fall and deposition from progressively more hypersaline platform waters up section, but waters stayed below gypsum precipitation (lack of gypsum or anhydrite pseudomorphs). A Fischer plot of accommodation change is constructed and correlated with previously constructed plots for Upper Albian successions of southern Croatia, and tested for regional trends in relative sea-level change.