Osady mezozoiczne na wschodnim przedgórzu Sudetów

Abstract

MESOZOIC DEPOSITS IN THE EASTERN SUDETEN FORELAND (POLAND)

Rocks of Mesozoic age are reported by the author to occur abt. 1.5 km. south of Nowa Cerekwia (Altstett) in the district of Głubczyce (Lower Silesia). A profile of Mesozoic deposits, about 2 m. thick, has been exposed there at the bottom of a basalt quarry. A thin bed of contact-metamorphic rock overlies the contact of basalt with the underlying Mesozoic deposits. Subcircular concretions of loam altered through thermic metamorphism, averaging 6 cm. in diameter, occur within this bed. One of the concretions, probably owing its origin to the contact of the Mesozoic with the Carboniferous, has been found to consist of Carboniferous greywacke with argillaceous fossiIiferous shale. The underlying rocks also display contact metamorphism. They have developed as smoky grey argillaceous shale with rod-Iike or salty cleavage and a low mica content. The rods and plates are arranged perpendicularly to the contact surface with basalt. The thickness of these shales is about 20 cm. Underlying them are non-bedded dark grey loams with poorly distinct slaty cleavage, attaining a thickness of up to 40 cm. Downwards they grade into grey marly non~bedded clays, carrying small amounts of glauconite. The full thickness of the exposed profile does not exceed 2 m. The age of the clays here described may with great probability be referred, to the Cretaceous on ground of the yielded fossil microfauna assigned to Arenobulimina sp., Ataxophragmium sp., Egerellina sp., Marsonella sp. and Textularia sp.