Relative Sea-Level Changes Recorded on an Isolated Carbonate Platform: Tithonian to Cenomanian Succession, Southern Croatia

Abstract

Superb sections of Tithonian to Cenomanian carbonates of the Adriatic (Dinaric) platform are exposed on the islands of southern Croatia. A succession approximately 1,800 m thick consists exclusively of shallow-water marine carbonates (limestone, dolomitized limestone, dolomite, and intraformational breccia), formed in a protected and tectonically stable part of the platform interior. Several phases of exposure and incipient drowning are recorded in the platform interior. Four are crucial for understanding the Late Jurassic to mid-Cretaceous evolution of the wider peri-Adriatic area: (1) latest Jurassic-earliest Cretaceous sea-level fall, (2) Aptian drowning, followed by (3) Late Aptian platform exposure, and (4) Late Albian-Early Cenomanian sea-level fall. Deciphering these complex events from the vertical and lateral facies distribution has led to an evaluation of facies dynamics and construction of a relative sea-level curve for the study area. This curve shows that long-term transgression during the Early Tithonian, Hauterivian, Early Aptian, and Early Albian, resulted in generally thicker beds deposited in subtidal environments of lagoons or shoals. Regression was characterized by shallowing-upward peritidal parasequences, with well-developed tidal-flat laminites commonly capped by emersion breccia and/or residual clay sheets (Early Berriasian, Barremian, Late Aptian, Late Albian). The southern part of the Dinarides was tectonically quiet during the Tithonian through Aptian; sea-level oscillations appear to have been the primary control on facies stacking. Some correlation exists between local sea-level fluctuations and the published global eustasy charts for the Tithonian through Aptian. A significant departure is recognized at the Albian-Cenomanian transition, suggesting that it was influenced by tectonics associated with the disintegration of the Adriatic (Dinaric) platform.

Depositional characteristics and constraints on the mid-Valanginian demise of a carbonate platform in the intra-Tethyan domain, Circum-Rhodope Belt, northern Greece

“…According to Gr eselle and Pittet (2010), Gr eselle et al (2011 the drowning phase reflecting a rapid sea-level rise was most likely preceeded by a sea-level fall and platform emergence. In this context, a regressive episode in midValanginian time is clearly recorded on the regional sea-level curves compiled for the Russian platform (Sahagian et al, 1996), the circum-Atlantic area (Ford and Golonka, 2003), the Arabian platform (Haq and Al-Qahtani, 2005), the Adriatic platform (Husinec and Jelaska, 2006), and the Vocontian Basin (Gr eselle and Pittet, 2010). Haq (2014) has postulated that the long-term global sea level trend reached its lowest value of the Cretaceous period in the mid-Valanginian.…”

“…Contrariwise, other studies indisputably reveal a sea-level fall involving progradation of sedimentary systems or subaerial exposure of shallow platforms (Funk et al, 1993;Sahagian et al, 1996;Rojay and Altiner, 1998;Altiner et al, 1999;Reh akov a, 2000;Wortmann and Weissert, 2000;Minkovska et al, 2002;Vilas et al, 2003;Husinec and Jelaska, 2006;Gawlick et al, 2008;Ivanova et al, 2008;Gr eselle and Pittet, 2010). According to Gr eselle and Pittet (2010), Gr eselle et al (2011 the drowning phase reflecting a rapid sea-level rise was most likely preceeded by a sea-level fall and platform emergence.…”

“…The stratigraphically controlled diagenetic products in the Porto Koufos Limestones provide evidence for minor karstification below an ancient exposure surface (Hillg€ artner, 1998;Husinec and Jelaska, 2006). The resulting vuggy porosity, dissolution micropipes and specific brecciation pattern, as well as the lack of other diagnostic features for near-surface meteoric diagenesis (e.g., root traces, calcretes), resulted from complex interplay of several factors including climate, duration of exposure, amplitude of the sea-level fall, existing mineralogy, and depositional texture (Saller et al, 1994a;Yilmaz and Altiner, 2006).…”

“…Therefore, the early Valanginian shallowing and subsequent mid-Valanginian demise of the Circum-Rhodope carbonate platform resulted from a major sealevel fall which was possibly linked to glacioeustacy (Gr eselle and Pittet, 2010), increased water storage on the continents as an effect of climate humidification (F€ ollmi, 2012), or various solid-earth factors such as dynamic topography and ridge-volume changes (Conrad, 2013;Haq, 2014). For comparison, it is noteworthy that occurrences of lower Valanginian regressive trend, midValanginian unconformity with locally manifested evidence for subaerial exposure, and/or upper Valanginian stratigraphic gap are particularly well documented in earliest Cretaceous intra-Tethyan platform carbonates from adjacent regions, including Italy, Croatia, Albania, Serbia, Romania, Bulgaria and Turkey (Mati cec et al, 1996;Rojay and Altiner, 1998;Bosellini et al, 1999;Altiner et al, 1999;Bucur and S as aran, 2005;Dragastan et al, 2005;Radoi ci c, 2005;Husinec and Jelaska, 2006;Gawlick et al, 2008;Ivanova et al, 2008;Mircescu et al, 2013;Bucur et al, 2014;Polavder, 2014).…”

Characteristics of a Triassic regional unconformity between the second and third shallow-marine depositional megasequences of the Karst Dinarides (Croatia)

“…The third megasequence deposition began during the Norian and consists of pure carbonate deposits that are the signature of an isolated carbonate platform depositional regime, only sporadically punctuated by "short" periods of subaerial exposure and pelagic drowning episodes (e.g. Vlahović et al 2005;Husinec and Jelaska 2006). Between two depositional megasequences, i.e.…”