Facies development of the Badenian (Middle Miocene) gypsum deposits in the Racławice area (Miechów Upland, southern Poland)

Anna Becker

Abstract


Rozwój facjalny gipsów badenu (środkowy miocen) w okolicy Racławic (Wyżyna Miechowska, południowa Polska)

The Middle Miocene (Badenian) gypsum sequence was investigated by means of facies analysis on the Miechów Upland in the environs of Racławice, about 40 km northeast of Cracow. The region lies at the northwestern margin of the Carpathian Foredeep and has been omitted in detailed investigations until now. Five gypsum facies were distinguished: giant gypsum intergrowths, grass-like gypsum, palisade gypsum, sabre gypsum and microcrystalline gypsum. Except for the palisade gypsum, the other facies were described from the adjacent Nida area. The vertical arrangement of the facies is generally the same along entire northern margin of the Carpathian Foredeep. The studied sequence is reduced in thickness (up to 30 m) in comparison to the Nida area (up to 50 m). The lower part of the section, composed of the giant gypsum intergrowths and grass-like gypsum, is distinctively reduced. It is often replaced by a thin layer of palisade gypsum. The microcrystalline gypsum and the sabre gypsum are the most common facies. The giant gypsum intergrowths and the grass-like gypsum occur in the northern part of the Racławice area, while the palisade gypsum dominates in the southern part. The gypsum basin of the Miechów Upland developed in a similar way as the basin of the Nida area, but was shallower and its brines underwent more often dilution. The basin-floor morphology probably showed a variety of features.read in the deeper waters of the northwestern Proto-Caribbean basin.

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