ASGP (2021), vol. 91: 203–251

A LOST CARBONATE PLATFORM DECIPHERED FROM CLASTS EMBEDDED IN FLYSCH: ŠTRAMBERK-TYPE LIMESTONES, POLISH OUTER CARPATHIANS

Mariusz HOFFMANN (1, 2), Bogusław KOŁODZIEJ (2, *) & Justyna KOWAL-KASPRZYK (3)

1 Soletanche Polska, Warszawa, Poland, deceased 2016
2 Institute of Geological Sciences, Jagiellonian University, ul. Gronostajowa 3a, 30-387 Kraków, Poland; e-mail: boguslaw.kolodziej@uj.edu.pl
3 Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland; e-mail: kowalj@agh.edu.pl
*) Corresponding author

Hoffmann, M., Kołodziej, B. & Kowal-Kasprzyk, J., 2021. A lost carbonate platform deciphered from clasts embedded in flysch: Štramberk-type limestones, Polish Outer Carpathians. Annales Societatis Geologorum Poloniae, 91: 203–251.

Abstract : Limestones designated the Štramberk-type are the most common carbonate exotic clasts (exotics) embedded in the uppermost Jurassic–Miocene flysch deposits of the Polish Outer Carpathians. About 80% of stratigraphically determinable carbonate exotics from the Silesian, Sub-Silesian and Skole units (nappes) are of Tithonian (mostly)–Berriasian (sporadically Valanginian) age. A study of these exotics revealed eight main facies types: coral-microbial boundstones (FT 1), microencruster-microbial-cement boundstones (FT 2), microbial and microbial-sponge boundstones (FT 3), detrital limestones (FT 4), foraminiferal-algal limestones (FT 5), peloidalbioclastic limestones (FT 6), ooid grainstones (FT 7), and mudstones-wackestones with calpionellids (FT 8). Štramberk-type limestones in Poland and the better known Štramberk Limestone in the Czech Republic are remnants of lost carbonate platforms, collectively designated the Štramberk Carbonate Platform. Narrow platforms were developed on intra-basinal, structural highs (some of them are generalized as the Silesian Ridge), with their morphology determined by Late Jurassic synsedimentary tectonics. An attempt was made to reconstruct the facies distribution on the Tithonian–earliest Cretaceous carbonate platform. In the inner platform, coral-microbial patch-reefs (FT 1) grew, while the upper slope of the platform was the depositional setting for the microencruster-microbial-cement boundstones (FT 2). Microbial and microbial-sponge boundstones (FT 3), analogous to the Oxfordian–Kimmeridgian boundstones of the northern Tethyan shelf (also present among exotics), were developed in a deeper setting. In the inner, open part of the platform, foraminiferal-algal limestones (FT 5) and peloidal-bioclastic limestones (FT 6) were deposited. Poorly sorted, detrital limestones (FT 4), including clastsupported breccias, were formed mainly in a peri-reefal environment and on the margin of the platform, in a high-energy setting. Ooid grainstones (FT 7), rarely represented in the exotics, were formed on the platform margin. Mudstones-wackestones with calpionellids (FT 8) were deposited in a deeper part of the platform slope and/or in a basinal setting. In tectonic grabens, between ridges with attached carbonate platforms, sedimentation of the pelagic (analogous to FT 8) and allodapic (“pre-flysch”) Cieszyn Limestone Formation took place. The most common facies are FT 4 and FT 1. Sedimentation on the Štramberk Carbonate Platform terminated in the earliest Cretaceous, when the platform was destroyed and drowned. It is recorded in a few exotics as thin, neptunian dykes (and large dykes in the Štramberk Limestone), filled with dark, deep-water limestones. Reefal facies of the Štramberk Carbonate Platform share similarities in several respects (e.g., the presence of the microencrustermicrobial-cement boundstones) with reefs of other intra-Tethyan carbonate platforms, but clearly differ from palaeogeographically close reefs and coral-bearing facies of the epicontinental Tethyan shelf (e.g., coeval limestones from the subsurface of the Carpathian Foredeep and the Lublin Upland in Poland; the Ernstbrunn Limestone in Austria and Czech Republic). Corals in the Štramberk Limestone and Štramberk-type limestones are the world’s most diverse coral assemblages of the Jurassic–Cretaceous transition.
The intra-basinal ridge (ridges), traditionally called the Silesian Cordillera, which evolved through time from an emerged part of the Upper Silesian Massif to an accretionary prism, formed the most important provenance area for carbonate exotic clasts in the flysch of the Silesian Series. They are especially common in the Lower Cretaceous Hradiště Formation and the Upper Cretaceous–Paleocene Istebna Formation. The Baška-Inwałd 204 M. HOFFMANN Et Al. In the Polish Outer Carpathians, shallow-water carbonate sedimentation is recorded only by carbonate clasts, redeposited bioclasts, and very rare, small, unrooted, poorly exposed klippen. Clasts of limestones are exotic to the dominant siliciclastic, uppermost Jurassic–Miocene flysch deposits. They were derived from extrabasinal and intra-basinal source areas of the Carpathian rocks, which periodically emerged and were destroyed. Such rocks were described as “exotic” since the 19th century (“exotischen Graniten”, “exotische Blöcke”; Morlot, 1847; Hohenegger, 1861). In the general geological literature, the term “exotic clasts” is usually used (Flügel, 2010, p. 172), whereas in the Polish geological literature, the term “exotics” (Polish “egzotyki” including also carbonate exotics), is also commonly applied. On the basis of fossils, facies and microfacies, these clasts (pebbles, rarely blocks) are mostly described as Devonian–Carboniferous (Malik, 1978, 1979; Burtan et al., 1983; Tomaś et al., 2004) and Upper Jurassic–lowermost Cretaceous (the present paper and references therein), more rarely Middle Jurassic (Książkiewicz, 1935, 1956a; Barczyk, 1998; Olszewska and Wieczorek, 2001), Early Cretaceous (Oszczypko et al., 1992, 2006, 2020; Krobicki et al., 2005), Late Cretaceous (Książkiewicz, 1956a; Gasiński, 1998) and Palaeogene in age (Leszczyński, 1978; Rajchel and Myszkowska, 1998; Leszczyński et al., 2012; Minor-Wróblewska, 2017). At the beginning of these studies, the focus was on small, unrooted klippen, namely the Andrychów Klippen (called also Klippes) near Wadowice (Zeuschner, 1849; Hohenegger, 1861; Uhlig, 1904; Książkiewicz, 1935, 1971b; Nowak, 1976; Gasiński, 1998; Olszewska and Wieczorek, 2001), and in Kruhel Wielki, near Przemyśl (Niedźwiedzki, 1876; Wójcik, 1907, 1913, 1914; Bukowy and Geroch, 1956; Morycowa, 1988; Olszewska et al., 2009), now poorly exposed. Subsequently, exotic pebbles, much more common and providing data on more facies, were studied more frequently. The first attempt to describe exotics, including crystalline rocks, was presented by Nowak (1927). Jurassic–Cretaceous carbonate exotics at Bachowice, containing facies unknown at other localities in the Polish Outer Carpathians, were described by Książkiewicz (1956a). The preliminary results of studies, which encompassed the entire spectrum of carbonate exotics from the western part of the Polish Outer Carpathians, were presented by Burtan et al.
(1984). Malik (1978, 1979) described both Palaeozoic and Mesozoic carbonate clasts in the Hradiště Sandstone of the Silesian Unit, but other studies were mostly concerned with the Štramberk-type limestones from selected outcrops. The studies of these limestones, if concerned with exotics at many localities, were focused on their fossil content (e.g., Kołodziej, 2003a; Bucur et al., 2005; Ivanova and Kołodziej, 2010; Kowal-Kasprzyk, 2014, 2018) or presented only the preliminary results of facies studies (e.g., Hoffmann and Kołodziej, 2008; Hoffmann et al., 2008). Carbonate platforms, the existence of which was deciphered from detrital carbonate components, are called lost carbonate platforms (e.g., Belka et al., 1996; Flügel, 2010; Kukoč et al., 2012). Clasts and other shallowwater components are, metaphorically, witnesses to lost carbonate factories (the term is taken from Coletti et al., 2015). Analyses of the age and lithology of exotic clasts have been applied in the reconstruction of the provenance areas of the clasts and their palaeogeography and the development of the sedimentary sequences of the Polish Outer Carpathians (e.g., Książkiewicz, 1956b, 1962, 1965; Unrug, 1968; Oszczypko, 1975; Oszczypko et al., 1992, 2006; Hoffmann, 2001; Krobicki, 2004; Słomka et al., 2004; Malata et al., 2006; Poprawa and Malata, 2006; Poprawa et al., 2006a, b; Strzeboński et al., 2017; Kowal-Kasprzyk et al., 2020). Štramberk-type limestones are most common among the exotics. It is a field term that refers to limestones, mostly beige in colour, that are supposed to be the age and facies equivalents of the Tithonian–lower Berriasian Štramberk Limestone in Moravia (Czech Republic; Eliáš and Eliášová, 1984; Picha et al., 2006). The Štramberk Limestone and the Štramberk-type limestones of both countries were deposited on platforms, attached to the intrabasinal ridges and margins of the basin of the Outer Carpathians. These platforms are collectively termed the Štramberk Carbonate Platform. The terms “Štramberk Limestone” and “Štramberk-type limestones” have been widely used in the area of the former Austro-Hungarian Empire for the field description of shallow-water limestones of assumed Late Jurassic age, usually occurring within flysch deposits of the Outer Carpathians. Upper Jurassic–lowermost Cretaceous shallow-water limestones in Romania (commonly forming mountains or ridges, e.g., Pleş et al., 2013, 2016), in Bulgaria and Serbia (Tchoumatchenco et al., 2006), and Ukraine (Krajewski and Schlagintweit, 2018), and in Turkey (Masse et al., 2015) sometimes are referred to as the Štramberk-type limestones as well. In the Austrian-German literature similar limestones in the Alps are known as the Plassen Limestone (e.g., Steiger and Wurm, 1980; Schlagintweit et al., 2005). Biostratigraphic studies revealed that some carbonate clasts, accounting for several percent of the exotics and commonly Ridge and the Sub-Silesian Ridge were the source areas for clasts from the Silesian and Sub-Silesian units (e.g., in the Hradiště Formation), while the Northern (Marginal) Ridge was the source for clasts from the Skole Unit (e.g., in the Maastrichtian–Paleocene Ropianka Formation).

Manuscript received 3 May 2020, accepted 7 August 2021