Lower Eocene to Lower Miocene Stratigraphy and Palaeoenvironment of ODP Site 643A, Norwegian Sea
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The focus of this study is the lower Eocene to lower Miocene succession in ODP Site 643A. The site is located in the Norwegian Sea, at the base of the Outer Vøring Plateau (OVP). We analysed dinocyst assemblages and calculated the relative input of soil organic matter using an organic proxy, the branched/isoprenoid tetraether (BIT) index. Our results suggest outer neritic or oceanic conditions during the deposition of the studied succession, and a progressive submerging of the OVP. A transition from a stratified oxygen-depleted water column into a mixed and well-oxygenated column is observed at ~41.2 Ma and might be connected with subsidence of the OVP. The variations in dinocyst abundance indicate that there was a connected surface water circulation within the Norwegian–Greenlandic Sea in the latest Lutetian. Our record also suggests that there was a good surface water exchange between the Norwegian Sea and the North Sea Basin during the earliest Oligocene and at the Oligocene–Miocene transition.
KeywordsDinocysts BIT Palaeoenvironment Palaeogene Norwegian Sea ODP Site 643A
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