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Analysis of lithology and microfacies of the Lower Cretaceous “Urgonian” complex in the Manín Straits section, the Manín Unit (Western Carpathians)

Fekete K.

Geology, Geophysics and Environment

2015

Vol. 41, no. 1

76--77

A sequence of the Jurassic-Cretaceous beds of the Manín Unit was exposed in the Manín Straits in the area of Middle Váh Valley (Strážovské Vrchy Mts.), east of the Považská Teplá village. Hettangian-Bajocian sandy crinoidal strata are uncovered at the beginning of the section which continues with thick-bedded reddish nodular limestones of Bathonian-Kimmeridgian Czorsztyn Fm (Ammonitico Rosso) with breccias and fragments of planktonic crinoids (Saccocoma sp.) in the basal part. Berriasian strata are probably missing. Upper parts consist of Lower Valanginian light gray Ladce Fm (biancone, maiolica) and Upper Valanginian Mráznica Fm. Section continues with Hauterivian-Lower Barremian Kališčo Fm with cherts. Dominant part of the Manín Straits consists of a typical member of the Manín Unit – organodetrital Lower Cretaceous “Urgonian-type” limestones. In the Manín Unit this complex is divided into organogenic reef to near-reef facies – the Manín Fm and into slope facies of organodetrital limestones, termed the Podhorie Fm by Borza et al. (1987), with lateral replacement of these two to a considerable extent coeval parts of one area of sedimentation (carbonate platform and its slope). Thickness of the “Urgonian limestones” in the Manín Straits attains around 90 m. According to Köhler (1980), only Barremian strata are represented here. The upper part was eroded before Albian. Basal part is represented by mainly gray to light gray massive limestones of the Podhorie Fm (Borza et al. 1987). They represent bioclastic debris derived from central part of the carbonate platform without corals and terrigenous admixture. Limestones of Podhorie Fm are characterized by intrabiopelmicritic/ intrabiopelsparitic texture (intraclast-biogenic-peloid wackestone/ packstone) with fragments of Barremian-Aptian foraminifers (Orbitolina sp., Dorothia sp., Valserina sp., Hedbergella sp.). They gradually pass into light gray organogenic massive fine grained rudist (Praecaprotina sp.,Offneria sp.) limestones of the Manín Fm with fragments of gastropods and benthic foraminifers (Boorová 1991). Texture of lime stones is intrabiosparitic/ intrabiosparruditic with rare presence of peloids (intraclast-rudist grainstone/ rudstone). The Manin Fm is terminated by hardground surface, which is followed by Albian-Cenomanian marlstones of the Butkov Fm with association of rare benthic and current planktonic foraminifers from the beginning of Late Albian Thalmanninella ticinensis ticinensis Zone (Boorová 1991).

Development and infill of Vistulian glacial Lake Gniew (N Poland) : a sedimentological analysis

Błaszkiewicz M., Gruszka B.

Geological Quarterly

2005

Vol. 49, No. 4

449--462

A substantial glaciolacustrine unit in northern Poland, between the valleys of the Vistula and Wierzyca rivers, was deposited in glacial Lake Gniew during the climatic amelioration of the Late Vistulian. It covers an area of 35 km2 and has an average thickness of 7m, but locally reaches over 20 m. Four sedimentary facies are distinguished. The silty/clayey rhythmites of facies A are interpreted as varves from the central lake bottom. They represent the initial stage of lake development. Facies B is formed by a single sand layer that is interpreted as a turbidite originating during lake shallowing due to self-drainage. Facies C consists of massive clay with dropstones and dump structures. Two hypothesis regarding its genesis are put forward: the first assumes sedimentation in a shallow basin with a high input of homogenous fine-grained suspended sediment, whereas the second explains the facies as a result of amuddy jökulhlaup, pouring into Lake Gniew and being sourced from another glacial lake; further research is required to interpret this facies reliably. Facies D consists of thick silty/clayey rhythmites that are interpreted as prodeltaic deposits.