LOWER CRETACEOUS SMALL BENTHIC FORAMINIFERA FROM BUCEGI MOUNTAINS (SOUTH CARPATHIANS) - PALEOECOLOGIC IMPLICATIONS

摘要

The paper presents the first published account of smaller agglutinated and calcareous benthic foraminifera from Lower Cretaceous (Valanginian - lowermost Hauterivian) marls, from the Bucegi Mountains, in the South Carpathians. Small benthic foraminifera, along with calcareous nannofossils, are used in paleoecological interpretations. The occurrence of Spirillina, Patellina and Lenticulina species indicates deep water. The occurrence of the benthic genus Spirillina indicates local dysaerobic conditions on the sea floor. Dysaerobic conditions are usually caused by high organic productivity in the surface-water. Zeugrhabdotus spp. are markers of high-fertility surface water in unstable environments such as oceanic sites of up welling or shelf areas where trophic conditions may have been enhanced by storms. The presence of Zoophycos trace fossils is indicative of dysaerobic conditions within sediments. Moreover, the presence of pyrite is also indicative of fluctuations in palaeoredox conditions.