engleski

Early Miocene (Ottnangian) coastal upwelling conditions along the southeastern scarp of the Bohemian Massif (Parisdorf, Lower Austria, Central Paratethys)

Lower Miocene clays of the Zellerndorf Formation and intercalated diatomites of the Limberg Member from the Alpine-Carpathian Foredeep in Lower Austria show distinct features for coastal upwelling conditions along the steep southeastern scarp of the Bohemian Massif during the Ottnangian. The sediments were deposited in a deep marine sublittoral environment, in a pelagic, deep-neritic zone. The communities of diatoms, calcareous nannoplankton and planktonic foraminifera clearly point to the influence of cold and nutrient-rich deep-water currents, typical for upwelling zones. The very high content of smectitic clay minerals in both the sediments and volcaniclastics of time-equivalent strata in this area indicate prominent acidic volcanic input at this time. Thus, besides the nutrient-rich deep-water currents, the induced high silica content in the sea also boosted biogenic productivity, especially for diatoms. The new species Nonion gudrunae Rögl n. sp. is described from the Ottnangian Zellerndorf Formation in the diatomite pit Parisdorf, and a lectotype of Nonion commune (d’ Orbigny, 1846) is designated.

Limberg Member; Zellerndorf Formation; diatomite; coastal upwelling; Nonion gudrunae Rögl n. sp.

Rad je prezentiran i na skupu 15th Conference on Upper Tertiary (Brno, May 31, 2007). Sažetak je objavljen u Zborniku (ISBN 978-80-210-4453-1), str. 15-16 ; poveznica http://www.nhm- wien.ac.at/Content.Node/forschung/geologie/mitarbe iter/pdfs/Scripta36_Roetzel_etal2007.pdf