The oldest stage of the Outer Carpathian evolution in the light of Oxfordian–Kimmeridgian exotic clast studies (southern Poland)

Abstract

In the Late Jurassic, the rifting process led to the disintegration of the southern margin of the North European Platform and to the opening of the Outer Carpathian flysch basin sedimentary system. The initial sediments accumulated in the northern part of the basin are related to both the destruction and resedimentation of older platform deposits. Since the sedimentary succession of this pre-flysch phase was consumed by the Miocene subduction, its only traces are represented, nowadays, by clasts preserved as exotics in the succeeding flysch deposits. Our analysis of foraminifers as well as calcareous and organic dinoflagellate cysts found in these exotics confirms the Oxfordian-early Kimmeridgian timing of the platform phase that preceded the opening of the flysch basin. The exotics are represented by three main facies types: sponge-microbial limestones, oncoid-intraclastic-Crescentiella limestones and fine-grained, biodetrital limestones with Saccocoma. These deposits are related to mid-ramp to outer-ramp settings. The land influence was rather weak, and these sedimentary settings were dominated by pelagic/hemipelagic accumulation. The studied facies are similar to facies types widely distributed over the northern shelf area of the Western Tethys (e.g., extra-Carpathian southern Poland, Carpathian Foredeep basement, southern Germany). In turn, coeval strata known from the part of the Magura Basin and of the Penninic-Pieninic Ocean, which were situated in more southern part of the Tethys, yielded different microfacies reflecting significant differences between the sedimentary settings of the study area and its southern extensions.

Seismic Characteristics and Development of the Upper Jurassic Carbonate Buildups from the Miechów Trough (Southern Poland)

“…The central and southern Polish part of the Late Jurassic depositional system in the south was connected with the Tethys Ocean (e.g., [11,72,74,90]). The inner ramp facies, composed mainly of oolitic and oncolitic deposits and different bioclastic grainstones, formed the northward-, north-westwardand/or westward-prograding shallow-water carbonate platform (see e.g., [17][18][19]71,91]).…”

“…The inner ramp facies, composed mainly of oolitic and oncolitic deposits and different bioclastic grainstones, formed the northward-, north-westwardand/or westward-prograding shallow-water carbonate platform (see e.g., [17][18][19]71,91]). The mid ramp facies represent mostly open shelf microbial-sponge deposits (e.g., [6,17,69,71,72,92]). These diversified deposits, sometimes categorized under the general term "sponge megafacies" [93,94], are built of microbial structures (see e.g., [26,95]) and siliceous sponges, and are present within the northern Tethyan shelf in Europe [68,96,97].…”

“…During the Late Jurassic, southern Poland formed an open shelf, or gently inclined carbonate ramp, that connected the epicontinental sea with Tethyan basins (cf., [28,71,72]). The study area is located within the central part of the Miechów Trough, approximately 50 km north-east from the city of Kraków (Figure 1).…”

Substrate type and palaeodepth do not affect the Middle Jurassic taxonomic diversity of crinoids

“…The roveacrinids represented by the genus Saccocoma are exclusive to the shallow marine Bathonian and/or Callovian carbonates of the Tatra Mountains and the Pieniny Klippen Belt (Tethyan province). Kowal-Kasprzyk, Krajewski & Gedl (2020) mentioned saccocomids from the Oxfordian-Kimmeridgian exotic clasts of the Outer Carpathians in southern Poland. Matyszkiewicz (1996) and Matyszkiewicz (1997) mentioned Saccocoma -calciturbidites resting on the slope beds of Oxfordian cyanobacterial-sponge carbonate buildups formed in the Polish epicontinental basin (for summary see Fig.…”

The Late Jurassic–Palaeogene Carbonate Platforms in the Outer Western Carpathian Tethys—A Regional Overview

“…The shallow-water carbonate platforms occurred on margins of the Protosilesian Basin from the earliest stages of its development, and they first constituted continuation of the epicontinental carbonate deposition that took place on the south margin of the North European Platform before its rifting. These pre-Carpathian Middle Jurassic to Kimmeridgian carbonate rocks are known from the Andrychów Klippen and Bachowice area [18,44,45], as well as from smaller exotic clasts found among the Carpathian turbiditic deposits (e.g., [46]). From the Jurassic to Oligocene, the carbonate sedimentation developed locally or regionally in shallow parts of the Outer Carpathian basins.…”