Thermo-Tectonic Development of the Wandel Sea Basin, North Greenland

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EGU2020-17188 https://doi.org/10.5194/egusphere-egu2020-17188 EGU General Assembly 2020 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License.

Thermo-tectonic development of the Wandel Sea Basin, North Greenland

Peter Japsen1, Paul F. Green2, and James A. Chalmers1 1Geological Survey of Denmark and Greenland (GEUS), Copenhagen, Denmark ([email protected]) 2Geotrack International, Melbourne, Australia ([email protected])

The Carboniferous to Palaeogene Wandel Sea Basin of North Greenland is an important piece in the puzzle of Arctic geology, particularly for understanding how the Paleocene–Eocene movement of the Greenland Plate relates to the compressional tectonics in the High Arctic; e.g. Eurekan Orogeny (arctic Canada), West Spitzbergen Orogeny (Svalbard) and Kronprins Christian Land Orogeny (North Greenland). We will refer collectively to these manifestations related to the movement of the Greenland Plate as the Eurekan Orogeny. Here, we present apatite fission-track analysis (AFTA) and vitrinite reflectance (VR) data combined with observations from the stratigraphic record to place constraints on the timing of key tectonic events.

Our study reveals a long history of episodic burial and exhumation since the collapse of the Palaeozoic fold belts along the east and north coasts of Greenland. Our results provide evidence for pre-Cenozoic phases of uplift and erosion in Early Permian, Late Triassic, Late Jurassic and mid- Cretaceous times, all of which involved removal of sedimentary covers that were 2 km thick or more.

Paleocene cooling and exhumation affected the major fault zones of the Wandel Sea Basin. The Paleocene episode thus defines the timing of the compressional event that caused folding and thrusting of Upper Cretaceous and older sediments along these fault zones. We conclude that the Paleocene inversion of the fault zones took place in the initial phase of the Eurekan Orogeny after the onset of seafloor spreading west of Greenland

Regional cooling, reflecting exhumation of the Wandel Sea Basin and surrounding regions, began at the end of the Eocene. Prior to the onset of exhumation, a cover of about 2.5 km of Paleocene–Eocene sediments had accumulated across a wide area. Northern Peary Land, north of the Harder Fjord Fault Zone, was uplifted about 1 km more than the area south of the fault zone during this episode. Regional denudation and reverse faulting that began at the end of the Eocene took place after the end of sea-floor spreading in the Labrador Sea and thus represent a post- Eurekan tectonic phase. A major plate reorganisation in the NE Atlantic and regional exhumation of West and East Greenland and adjacent Arctic regions took place at the same time, coinciding with a minimum of spreading rates in the NE Atlantic followed by expansion of the Iceland Plume.

Cooling from mid-late Miocene palaeotemperatures at sea level correspond to burial below a rock column about 1.8 km thick.

The preserved sedimentary sequences of the Wandel Sea Basin represent remnants of thicker strata, much of which was subsequently removed during multiple episodes of uplift and erosion. The thickness of these sedimentary covers implies that they must have extended substantially beyond the present-day outline of the basin, and thus that it at times was coherent with the sedimentary basins in the Arctic, as has been suggested from stratigraphic correlations.