DOI: 10.1007/s00531-015-1203-1
Scopus记录号: 2-s2.0-84945489392
论文题名: Early Eocene volcanic ashes on Greifswalder Oie and their depositional environment, with an overview of coeval ash-bearing deposits in northern Germany and Denmark
作者: Obst K. ; Ansorge J. ; Matting S. ; Hüneke H.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2015
卷: 104, 期: 8 起始页码: 2179
结束页码: 2212
语种: 英语
英文关键词: Bentonite
; Cementstones
; Fur and Ølst Formations
; Greifswalder Oie
; Lamstedt and Schlieven Formations
; Mo-clay
; North Sea Basin
; Rift volcanism
; “Untereozän 1” Formation
Scopus关键词: bentonite
; carbonate sediment
; clay
; depositional environment
; Eocene
; reworking
; rift zone
; sequence stratigraphy
; volcanic ash
; volcanism
; Atlantic Ocean
; Denmark
; North Sea
英文摘要: 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 55 Ma 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. © 2015, Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945489392&doi=10.1007%2fs00531-015-1203-1&partnerID=40&md5=84f50089f57c85774e9fac902e334107
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70244
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Geological Survey of Mecklenburg-Vorpommern, LUNG M-V, Goldberger Str. 12, Güstrow, Germany; Institute of Geography and Geology, University of Greifswald, F.-L.-Jahn-Str. 17a, Greifswald, Germany
Recommended Citation:
Obst K.,Ansorge J.,Matting S.,et al. Early Eocene volcanic ashes on Greifswalder Oie and their depositional environment, with an overview of coeval ash-bearing deposits in northern Germany and Denmark[J]. International Journal of Earth Sciences,2015-01-01,104(8)