Calcareous nannoplankton of the Globigerina Marls (Leluchów Marls Member), Magura Nappe, West Carpathians
Abstract
Nannoplankton wapienny margli globigerynowych (ogniwo margli z Leluchowa), płaszczowina magurska, Karpaty Zachodnie
The Magura Nappe, the largest and innermost unit of the outer Carpathians consists of very thick turbidite sequences. In the Leluchów section the upper portion of these sequences includes a regional correlative horizon of pelagic deposits, known as the Globigerina Marls (Sheshor Horizon in the Ukrainian Carpathians). Leluchów section is not typical for the Magura Nappe because it includes green shales, Globigerina Marls and the Menilite Beds. Such sequences are typical for other, more external units of the Polish Carpathians. The Globigerina Marls of Leluchów are represented by a 4 m thick complex of alternating green, olive and red marls or marly shales (Leluchów Marl Member of the Malcov Formation). The Globigerina Marls contain a fairly abundant, diversified and moderately well preserved calcareous nannoflora. The assemblage is dominated by Late Eocene species, although reworked Cretaceous, Paleocene and Early Eocene taxa were also found. The association of Isthmolithus recurvus, Discoaster barbadiensis and Discoaster saipanensis is believed to be indicative for the combined interval of zones NP 19-20. On the basis of the pelagic foraminifers the Eocene-Oligocene boundary has been earlier determined in the upper part of the Globigerina Marls. The Globigerina Marls are covered by a few meters thick complex of black shales with intercalations of hornstones and tuffites (Smereczek Shale Member of the Malcov Formation). The deposition of the Globigerina Marls corresponded to a drop in the global sea-level. This event was associated with the beginning isolation of the Carpathian Basin from the Tethyan domain.
The Magura Nappe, the largest and innermost unit of the outer Carpathians consists of very thick turbidite sequences. In the Leluchów section the upper portion of these sequences includes a regional correlative horizon of pelagic deposits, known as the Globigerina Marls (Sheshor Horizon in the Ukrainian Carpathians). Leluchów section is not typical for the Magura Nappe because it includes green shales, Globigerina Marls and the Menilite Beds. Such sequences are typical for other, more external units of the Polish Carpathians. The Globigerina Marls of Leluchów are represented by a 4 m thick complex of alternating green, olive and red marls or marly shales (Leluchów Marl Member of the Malcov Formation). The Globigerina Marls contain a fairly abundant, diversified and moderately well preserved calcareous nannoflora. The assemblage is dominated by Late Eocene species, although reworked Cretaceous, Paleocene and Early Eocene taxa were also found. The association of Isthmolithus recurvus, Discoaster barbadiensis and Discoaster saipanensis is believed to be indicative for the combined interval of zones NP 19-20. On the basis of the pelagic foraminifers the Eocene-Oligocene boundary has been earlier determined in the upper part of the Globigerina Marls. The Globigerina Marls are covered by a few meters thick complex of black shales with intercalations of hornstones and tuffites (Smereczek Shale Member of the Malcov Formation). The deposition of the Globigerina Marls corresponded to a drop in the global sea-level. This event was associated with the beginning isolation of the Carpathian Basin from the Tethyan domain.