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

• Published in: Cretaceous research Vol. 55; pp. 84 - 115
• Main Authors: Chatalov, Athanas, Bonev, Nikolay, Ivanova, Daria
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-07-2015
• Subjects: Berriasian; Carbonate platform; Circum-Rhodope belt; Greece; Intra-Tethyan; Valanginian; Intra-Tethyan; Greece; Berriasian; Circum-Rhodope belt; Valanginian; Carbonate platform
• ISSN: 0195-6671; 1095-998X
• DOI: 10.1016/j.cretres.2015.02.001

Two platform-type carbonate successions of Berriasian to early Valanginian age are exposed in the eastern Circum-Rhodope belt which extends from the Chalkidiki Peninsula to the Thrace region in northern Greece. On the basis of new sedimentological and biostratigraphic results and analysis of published palaeomagnetic data, the Porto Koufos Limestones and Aliki Limestones are interpreted as deposits of a formerly unknown earliest Cretaceous carbonate platform in the Western Tethys realm. This Circum-Rhodope carbonate platform existed in tropical latitudes of the intra-Tethyan domain on the northern shelf area of the small Vardar oceanic basin. It was characterized by limited regional extent, remoteness from land, and short lateral transitions into deeper basin areas. Predominantly skeletal sediments with various microencrusters were produced along with variable amounts of lime mud, marine cements, peloids, intraclasts, aggregate grains, ooids and microbialites. The microfacies analysis of limestones formed around the Berriasian–Valanginian boundary indicates the configuration of a rimmed shelf with restricted lagoon, open lagoon, reef margin, fore-reef and upper slope depositional environments. During the early Valanginian a change from photozoan to heterozoan mode of carbonate production occurred mainly as a result of climate cooling. Deposition continued in protected lagoon, shoal and near-shoal settings implying a ramp-like morphology of the platform. Finally, a shift from skeletal to non-skeletal carbonate deposition took place as a consequence of high seawater carbonate saturation and possibly coeval increase of the marine trophic levels. A major sea level fall and climate cooling were the prime palaeoenvironmental controls that caused decline of the shallow-water carbonate factory and subsequent demise of the Circum-Rhodope carbonate platform in mid-Valanginian time that was followed by a long-term subaerial exposure and karstification which continued at least until the middle Eocene. The new results can be used for correlation with other shallow marine carbonates deposited in the intra-Tethyan domain during the earliest Cretaceous. Also, they appear to be of critical significance to decipher the Mesozoic geodynamic evolution of the Circum-Rhodope belt and adjacent tectonic zones.
•Circum-Rhodope carbonate platform developed in the tropical Intra-Tethyan domain.•Berriasian–earliest Valanginian photozoan carbonates were formed on a rimmed shelf.•A non-rimmed platform with heterozoan assemblages evolved in the early Valanginian.•A shift to non-skeletal sedimentation marked the decline of the carbonate factory.•Sea level fall and cooling were main controls on the mid-Valanginian platform demise.