International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

LITHOSTRATIGRAPHY AND DEPOSITIONAL ENVIRONMENT OF LOWER–MIDDLE JURASSIC CRINOIDAL LIMESTONE FORMATIONS OF THE VYSOKA NAPPE UNIT (MALE KARPATY MTS., WESTERN CARPATHIANS)

Pages: 329 - 339

Authors: EDUARD KOSA

Abstract: The Lower-Middle Jurassic sequence of the Vysoka Unit in the Male Karpaty Mts. (Western Carpathians, Slovakia) comprises a complex of crinoidal limestones. The paper suggests newly dividing this unit into four formations: Trlenska Fm., Vyvrat Fm., Pristodolok Fm. and Vils Fm., all of which are described in detail. Two of them, the Vyvrat and the Pristodolok Fms., are defined as new formal lithostratigraphic units. A connection is supposed between rhythmical facies changes in these sediments and relative sea level fluctuation. Two significant regressions are recognisable in a generally shallowing upward sequence with an uncertain number of cycles of lower order between them. The influence of eustatic and regional tectonic activity control on relative sea level changes has been not distinguished. The curve of sea level changes suggested by sequence stratigraphic analysis is comparable to the curve published by Haq et al. (1988). Lateral facies changes have been studied across the Vysoka Nappe Unit. The Lower-Middle Jurassic crinoidal complex is a part of a slope apron rimming the toe-of-slope of a carbonate plateau which probably originated due to tectonic collapse of the large Triassic carbonate platform during the early Jurassic. Its proximal development (near to apex) was recognized at the SW and the distal development at the NE edge of the Vysoka Unit. Sedimentation of the crinoidal limestones was terminated by an abrupt rise of the relative sea level and followed by deposition of nodular limestone formations.

Keywords: Lower Jurassic, Western Carpathians, carbonate sedimentology, lithostratigraphy, sequence stratigraphy, sea level change, slope apron, crinoidal limestone

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