Integrated studies of Late Jurassic neptunian dykes from central Poland

• Autorzy: Barski M. , Ostrowski S.
• Konferencja: International Congress on the Jurassic System (7 ; 06-18.09.2006 ; Kraków, Poland)
• Języki publikacji: EN

Abstrakty

EN

Steeply dipping clastic dykes cutting through the Middle Jurassic clays with ironestone nodules have been exposed in three localities at Wieluń, Częstochowa and Zawiercie in central Poland. The dykes are grey calcareous, structureless sandstones, 5 to 10 cm wide running roughly along the NE-SW direction which corresponds approximately to system of faults in the area. Palynological analysis of the internal sediment from the dykes revealed mixed assemblages of the Middle (Bajocian-Bathonian), and the Upper Jurassic (Oxfordian – Lower Kimmeridgian) Dinoflagellate cyst taxa. The latter consist of Systematophora areolata, Ctenidodinium ornatum, Gonyaulacysta jurassica jurassica, Endoscrinium luridum, Endoscrinium galeritum, Leptodinium subtile and Scriniodinium crystallinum. Rich hydrothermal calcite mineralization occurs mainly where dykes cut ironestone nodules. Hydrotermal mineralization is composed of coarse palisadic crystals ranging form 2.5 to 6 mm in lenght. Cement of sandstones is also composed of hydrotermal calcite. Fluid inclusion analysis of palisadic crystals (performed by Prof. Andrzej Koz.owski) yielded homogenisation temperatures in range of 53 up to 72°C. Gradual decreasing of homogenisation point and change in composition of fluids from hydrotermal to more marine fluids is observed from dyke walls, toward the centre of the dyke. Fluid inclusion analysis confirms mixed, hydrotermal-neptunian genesis of dykes with stages postulated on the basis of thin section observations. Presented work demonstrates necessity of integrated geological studies to improve sedimentological and tectonic reconstructions.The origin of the dykes was related with synsedimentary tectonics during Late Jurassic (Oxfordian - Early Kimmeridgian) which controlled the facies distribution within the sponge megafacies of the Polish Jura Chain area.

Słowa kluczowe

EN

neptunian dyke; dinocyst stratigraphy; fluid inclusion

• Wydawca: Państwowy Instytut Geologiczny - Państwowy Instytut Badawczy
• Czasopismo: Volumina Jurassica
• Rocznik: 2006
• Tom: Vol. 4, no. 1
• Strony: 78--79

Twórcy

autor

Barski M.

autor

Ostrowski S.

• Institute of Geology, Faculty of Geology, Warsaw University, Al. Żwirki i Wigury 93, PL-02089 Warszawa, Poland,