INTERRELATIONS BETWEEN THE TECTONOMORPHIC HISTORY OF THE ARCTIC AND ITS PAST ENVIRONMENTAL CHANGESPart I: Cenozoic tectonothermal evolution of North and Northeast Greenland

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The Wandel Hav Mobile Belt is situated at the northeastern corner of Greenland and was located in the central part of the Paleogene Eurekan orogen, formerly connecting the Canadian High Arctic in the West with the Barents Shelf in the East. We hypothesize that the Eurekan orogen has influenced the climatic evolution of the Arctic in that topography associated with Eurekan deformation may have formed the nucleus for assumed Eocene continental glaciation of Greenland. Continental glaciation of Greenland was postulated based on the occurrence of ice rafted debris in offshore sediments from ~44 Ma onwards. For this part of the study, we aim to test the basic prerequisite of our hypothesis - i.e., enhanced tectonic movements associated with enhanced erosion and thus presumably topography formation at the right time to initiate continental glaciation of Greenland at ~44 Ma - by applying thermochronological dating methods to onshore and offshore samples of North(-east) Greenland. In a companion proposal – for which this study will also provide reference material and data – we aim to investigate the provenance of offshore ice rafted debris, thus obtaining information on glaciated source areas and iceberg pathways during Eocene, Oligocene and Miocene times. After Eurekan deformation ceased, the tectonic regime of the Wandel Hav Mobile Belt changed to (trans-)tension, which eventually led to the separation of Greenland from the Eurasian continent and the opening of the Fram Strait. The Fram Strait forms the only deep water connection of the Arctic Ocean with other oceans, and thus its opening strongly impacted on the environmental and climatic evolution of the Arctic. Previous studies postulated widening of the Fram Strait during the mid Miocene and related this to regional uplift and heating, which may coincide with the change from seasonal to perennial sea ice cover in the Arctic Ocean. In the past, this mid Miocene thermotectonic event could not be dated precisely, thus inhibiting temporal correlations with environmental changes. Vitrinite reflectance data from the Wandel Hav region, however, suggest post Eurekan (mid Miocene?) heating of the coastal regions at temperatures sufficiently high to allow for direct dating by thermochronological analyses. Thus, the second major aim of this study is to decipher and date thermotectonic processes that influenced the Greenland side of the Fram Strait margin subsequent to Eurekan deformation.