Neogene and Quaternary dinoflagellate cyst, foraminiferal, and molluscan biostratigraphy and paleoclimatology and paleoenvironment of the Lille Toende borehole, southern Jylland, Denmark

摘要

The Miocene beds of the Lille Toende borehole, southern Jylland (Denmark) was studied by means of dinoflagellate cysts, foraminifers, and mollusks. The biostratigraphy based on the three different fossil groups is compared, and correlations with northwest European and international standard chronostratigraphic units is attempted. This dates the northwest European 'Middle Miocene' as older than the standard Middle Miocene. Paleoecological interpretations (paleodepth, paleotemperature, paleosalinity) based on dinoflagellate cysts and foraminifers is described in details. The Arnum formation was found to have been deposit in an inner neritic environment, possibly with reduced salinity, and with subtropical sea temperatures, the winter surface temperatures was found to above 10 deg C. The Hodde Formation and the Middle Miocene part of the Gram Formation was deposited under middle-outer neritic paleoenvironmental conditions and with fairly similar paleotemperatures. The Late Miocene part of the Gram Formation was deposited under outer neritic paleoenvironment conditions, but possibly also under falling sea temperatures. Apparently, the sea level did in general rise until it reached a maximum near Tortonian-Messinian boundary. (au) (1 map, 84 refs.)