The sedimentary provenance of Palaeocene – Eocene sandstones from the Svalbard Central Basin and implications for the Palaeocene hydrocarbon plays on the southwest Barents shelf

The thick mud-dominated Palaeogene Torsk Formation that was deposited on the western margin of the Barents Shelf is an underexplored yet proven play on the Barents Shelf. Despite two gas discoveries, exploration results of these targets have been mixed. A contributing factor to this is due to reduced confidence in regional geological and reservoir prediction models because the sedimentary source for the clastic reservoirs is uncertain.

In the Palaeogene, candidate sedimentary source areas for clastic sediment on the western Barents Shelf include the local basement highs (Stappen / Loppa high), northern Fennoscandia and northeast Greenland. The aim of this sedimentary provenance study was to determine which of these disparate regions was most likely. This was achieved through examining Paleocene and Eocene sandstone samples from well BH10-2008, drilled in the Central Basin on Svalbard. The study included the petrography of 13 samples and 744 detrital mineral chemical, isotopic and geochronological analyses. The signals are compared with similar datasets from the Torsk Formation on the southwest Barents Shelf in order to better constrain Palaeogene sand dispersal.

A major sedimentary provenance change is recorded in the well, consistent with field evidence and other outcrop-based sedimentary provenance studies conducted on the Central Basin. The sedimentary source region changed from one within northeast Svalbard to one from within northeast Greenland in the Early Eocene, as a response to the evolving Eurekan Orogeny. The Eurekan provenance signature is not seen on the western Barents Shelf and the provenance data from these wells suggest sources from Greenland and the developing Eurekan Orogen can be discounted. Instead, the sediment is inferred to have been sourced from local basement highs (Stappen / Loppa high) due to its resemblance with the samples from the Central Basin, which are inferred to have been sourced from northeast Svalbard.

This study provides new constraints on the Paleogene paleogeography and sand dispersal patterns. It suggests that whilst prevalent in Svalbard, sediment from the developing Eurekan Orogen may not have reached the western Barents shelf. Instead, the local topographic highs were the dominant source area throughout the deposition of the Torsk Formation.