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Sedimentary dynamics and main events in the evolution of the Adriatic-Dinaric Carbonate Platform (Dinaric Karst, Croatia)

The Adriatic-Dinaridic carbonate platform (ADCP ; also referred to as the Adriatic Carbonate Platform – AdCP), was one of the largest Mesozoic platforms in the Mediterranean region (central Tethys). Today, the ADCP strata comprise a heavily deformed, 4-6.5 km thick, Lower Jurassic to Paleocene succession of almost pure carbonate deposits. These deposits are part of a thicker (4-8.5 km), predominantly carbonate succession whose deposition took place for >270 myr (from at least the Carboniferous to the Late Eocene), and which forms most of the present-day Croatian Karst (External or Outer) Dinarides. This succession was originally deposited on the Adriatic microplate (Adria), which during the Mesozoic was a large lithospheric promontory on the NE margin of the African plate. The succession is now incorporated into a complex imbricated thrust and fold belt (with a SW vergence) extending for more than 600 km along the NE Adriatic coast. The ADCP basement is composed of Variscan (Upper Carboniferous) to Lower Triassic carbonate-siliciclastic strata and of predominantly carbonate Middle Triassic deposits that formed in an epeiric sea along the northern Gondwana margin. The tectonic activity, which culminated by regional Middle Triassic volcanism recorded throughout Adria, resulted in the formation of a large isolated megaplatform that consisted of the ADCP, Apenninic, and Apulian carbonate platforms. This large isolated intraoceanic carbonate platform was characterized by a very thick succession, including the Main Dolomite (Hauptdolomite) Formation. The ADCP became a separate entity during the Early Jurassic by formation of the Adriatic Basin that connected the Ionian and Belluno Basins. This event coincided with the widely recognized Toarcian oceanic anoxic event (OAE). Influence of global OAEs can be also recognized within the Lower Aptian (OAE-1a) and Cenomanian/Turonian (OAE-2) deposits. Jurassic and Cretaceous ADCP strata represent a thick carbonate succession accumulated predominantly in shallow-marine, tropical-water platform environments of similar morphology, subsidence rate and depositional patterns to those of the present-day Bahama Banks. Final disintegration of the ADCP was related to the latest Cretaceous to Paleogene Alpine orogenesis that was at first recognized by a collision-induced diachronous subaerial exposure of various parts of the platform, followed by the formation of foreland basins.

Sedimentary dynamics; Main events; Adriatic-Dinaric Carbonate Platform; Dinaric Karst; Croatia

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