Biostratigraphy and Paleoenvironment in the Neogene of the High Northern Latitudes - Insights from the palynomorph record of ODP Hole 907A in the Iceland Sea
The Neogene is of crucial importance for our understanding of Earth s climate evolution as it was finally pushed into the cold Quaternary climate with its major glaciations in the high northern latitudes. Notwithstanding, the response of the high northern latitudes to this Cenozoic transition from t...
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| Other Authors: | , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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Universität Bremen
2012
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| Online Access: | https://media.suub.uni-bremen.de/handle/elib/351 https://nbn-resolving.org/urn:nbn:de:gbv:46-00102719-11 |
| Summary: | The Neogene is of crucial importance for our understanding of Earth s climate evolution as it was finally pushed into the cold Quaternary climate with its major glaciations in the high northern latitudes. Notwithstanding, the response of the high northern latitudes to this Cenozoic transition from the Greenhouse into the Icehouse world yet remains poorly constrained due to the virtual absence of calcareous microfossils in high latitude Neogene sediments. This thesis examines the influence of the long-term climate deterioration on Miocene to Pliocene marine palynomorph assemblages (dinoflagellate cysts, prasinophyte algae, acritarchs) of ODP Hole 907A in the Iceland Sea, a sensitive area physically close to the growing Greenland ice-sheet, which experienced the effects of migrating ocean currents and sea-ice cover. Based on the pristine paleomagnetic record of Site 907, the principal aim of this thesis is to enhance the biostratigraphic application of organic-walled microfossils for (supra)regional correlations in these largely biogenic carbonate free sediments, and to utilize them for paleoenvironmental reconstruction in order to provide new insights into the Neogene history of the Iceland Sea. This thesis provides absolute age control on a suite of twenty-four dinoflagellate cyst and two acritarch bioevents for the first time in the Neogene of the high northern latitudes. These magnetostratigraphically-calibrated events have been compared across the North Atlantic and adjacent seas to critically evaluate their potential for biostratigraphic correlations within the high latitudes, but also with the mid- and low latitudes. Results show that seven species are useful for supraregional biostratigraphic correlations within the Nordic Seas, and four allow integrating the latter with the mid-latitude North Atlantic. Furthermore, this study highlights four species potentially useful for correlating mid-latitude sequences to the Central Arctic Ocean. Although an additional number of species appears to be valuable on a ... |
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