Biofacjalna struktura karpackiego neogenu Polski (opolian-miopliocen)

Abstract

BIOFACIES STRUCTURE OF THE CARPATHIAN NEOGENE (OPOLIAN-MIOPLIOCENE) IN POLAND Summary Three problem groups: fauna, biology, and geology, form the basis for reconstruction of internal bio-geo- ecofacies structure of the Neogene (Opolian-Miopliocene) in the Carpathians and Carpathian Foredeep and its correlation with strata from external zone of the foredeep (Silesia, Holy Cross Mts, and Lublin and Roztocze areas). Characteristic biolithofacies of the Opolian, Bochenian, Grabovian, Sarmatian, and Miopliocene are differentiated (Table. 1) and their paleogeographic ranges outlined (J. Urbaniak 1982). Sedimentary zones of the above facies appear determined by paleogeography of southern coastal area, presence of the Carpathian - Miocene threshold (NW - SE oriented), and evolution and resonance of tectonic modification of the Carpathian area. In the Opolian, there are differentiated northern Vaginella zone (open pelagic neritic at contact with sublittoral and littoral), Lithothamnium-Heterostegina (littoral-lagoon-continental), and southern zone, situated within Carpathian neritic one and differing in bathymetry and ecology (littoral-neritic-continental-brackish). Bochenian zones include southern, supra-Carpathian zone of Spiratella-Chodenice evaporitic sedimentation (Łopuszka Wielka sedimentary "kettle") and that of facies-varying sedimentation of evaporitic member sensu stricto in the basin (Lower Bochenian or Upper Vielician), and the Grabovian - a zone of littoral sedimentation in E-W-oriented bet, southern, "closed" neritic sublittoral zone, and northern neritic, open sea sublittoral zone. The Carpathian Sarmatian (Skole unit) represents the Anomalinoides dividens - Elphidium reginum zone of an open sea with eastern features. Marine Miocene sediments developed in continental facies in marginal zone of the Carpathian overthrust were differentiated as Miocene pseudofacies (Upper Opolian-Miopliocene-Quaternary). Continental (Sarmatian-Miopliocene) sediments of southern part of the Carpathians were differentiated as the Domański Wierch fresh-water molasse facies. In analysing facies structure of marine sediments of the Carpathian Neogene a special attention should be paid to interstratigraphic sedimentary-facies series (Opolian-Grabovian Lithothamnium monolith), "chimney" evaporitic facies (Lower-Upper Badenian), and chain facies of Grabovian littoral sedimentary zone. Crossing of vertical (chronostratigraphic) and horizontal (paleogeographic) sedimentary-facies series of one of features typical of facies model for marine Carpathian Neogene. This is reflected by complex internal nature of facies, i.e. Łopuszka Wielka Spiratella-gypsum chemobiofacies or Broniakówka-Siedliska evaporitic-algal (evaporitic- Lithothamnium) chemobiofacies. Stratigraphic-paleogeographic series cross with zone another at norm al angle. This may ex plain some controversial questions of facies development of the evaporitic horizon, i.e. those connected with lateral passage of chlorine-sulfate facies into the carbonate-Lithothamnium. The synthesis of stratigraphic-facies structure of the Carpathian Neogene is given in the tabular-graphic form (Table).