caa a22 4500 606149910 CHVBK 20210128100536.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s00531-015-1203-1 doi (NATIONALLICENCE)springer-10.1007/s00531-015-1203-1 Early Eocene volcanic ashes on Greifswalder Oie and their depositional environment, with an overview of coeval ash-bearing deposits in northern Germany and Denmark [Elektronische Daten] [Karsten Obst, Jörg Ansorge, Sabine Matting, Heiko Hüneke] Unconsolidated bentonites and carbonate-cemented volcanic ashes occur in northern Germany within the clay sequence of the Lamstedt and Schlieven Formations documented by several wells. Ash-bearing carbonate concretions (so-called cementstones) are also known from glacially transported rafts and erratic boulders on the Baltic Sea island Greifswalder Oie, representing the easternmost exposures of early Eocene sediments in the North Sea Basin. The ashes can be correlated with water-lain ashes of the Danish Fur and Ølst Formations (mo-clay) generated during the opening of the North Atlantic Ocean about 55Ma ago. Two types of cementstones can be distinguished on the basis of the mineralogical composition, sedimentary features and fossil content. Greifswalder Oie type I contains a black, up to 12-cm-thick ash deposit that follows above two distinct thin grey ash layers. The major ash unit has a rather homogeneous lower part; only a very weak normal grading and faint lamination are discernible. In the upper part, however, intercalations with light mudstone, in part intensively bioturbated, together with parallel and cross-lamination suggest reworking of the ash in a shallow marine environment. Major and trace element compositions are used to correlate type I ashes with those of the Danish-positive series which represent rather uniform ferrobasalts of the Danish stage 4, probably related to the emergence of proto-Iceland. In contrast, type II ash comprises a single, normally graded, about 5-cm-thick layer of water-lain air-fall tuff, which is embedded in fine-grained sandstone to muddy siltstone. Type II ash is characterised by very high TiO2 but low MgO contents. Exceptional REE patterns with a pronounced positive Eu anomaly suggest intense leaching of the glass that hampers exact correlation with pyroclastic deposits within the North Atlantic Igneous Province. Springer-Verlag Berlin Heidelberg, 2015 Cementstones nationallicence Bentonite nationallicence Mo-clay nationallicence "Untereozän 1” Formation nationallicence Fur and Ølst Formations nationallicence Lamstedt and Schlieven Formations nationallicence Greifswalder Oie nationallicence North Sea Basin nationallicence Rift volcanism nationallicence Obst Karsten Geological Survey of Mecklenburg-Vorpommern, LUNG M-V, Goldberger Str. 12, 18273, Güstrow, Germany aut Ansorge Jörg Institute of Geography and Geology, University of Greifswald, F.-L.-Jahn-Str. 17a, 17489, Greifswald, Germany aut Matting Sabine Geological Survey of Mecklenburg-Vorpommern, LUNG M-V, Goldberger Str. 12, 18273, Güstrow, Germany aut Hüneke Heiko Institute of Geography and Geology, University of Greifswald, F.-L.-Jahn-Str. 17a, 17489, Greifswald, Germany aut International Journal of Earth Sciences Springer Berlin Heidelberg 104/8(2015-11-01), 2179-2212 1437-3254 104:8<2179 2015 104 531 https://doi.org/10.1007/s00531-015-1203-1 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00531-015-1203-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Obst Karsten Geological Survey of Mecklenburg-Vorpommern, LUNG M-V, Goldberger Str. 12, 18273, Güstrow, Germany aut NATIONALLICENCE 700 1- Ansorge Jörg Institute of Geography and Geology, University of Greifswald, F.-L.-Jahn-Str. 17a, 17489, Greifswald, Germany aut NATIONALLICENCE 700 1- Matting Sabine Geological Survey of Mecklenburg-Vorpommern, LUNG M-V, Goldberger Str. 12, 18273, Güstrow, Germany aut NATIONALLICENCE 700 1- Hüneke Heiko Institute of Geography and Geology, University of Greifswald, F.-L.-Jahn-Str. 17a, 17489, Greifswald, Germany aut NATIONALLICENCE 773 0- International Journal of Earth Sciences Springer Berlin Heidelberg 104/8(2015-11-01), 2179-2212 1437-3254 104:8<2179 2015 104 531