Late Cretaceous to Paleogene sand provenance, deposition and tectonomagmatic development in the southern Møre Basin, Norway

<p>Upper Cretaceous and Paleocene sandstone strata represent promising reservoirs along the NE Atlantic margins, including new discoveries in recent years that has spurred increased activity in the area. Exploration and seismic imaging is complicated by massive Paleocene magmatism related to late rifting and early breakup, forming voluminous sill and dyke complexes hosted in the sedimentary succession and extrusive complexes, such as volcanic edifices and lava flows along the margin. Such igneous activity may have played an important role in the thermal and chemical history of reservoir zones. Their diagenetic properties as well as their physical appearance is expected to have been altered by the intrusions, breaking predictive trends otherwise common for deep-marine sedimentary strata. A new understanding of the nature and implication of igneous processes and deposition of sediments, combined with new understanding of sand source-to-sink systems in the region, is thus important to better evaluate the prospectivity of the southern Møre Basin. The focus of this project will therefore be to asses sand provenance and depositional systems in basins in this area by incorporating on shore field work with integrated borehole and seismic studies. The main goal is to develop a new understanding of deposition of sand fairways during the Late Cretaceous and Paleogene to better understand this part of the break-up history of the NE Atlantic.</p>

New insights into reservoir sand provenance in the Exmouth Plateau and Browse Basin

A pilot study to determine if zircons present in reservoir facies of the North West Shelf can be used to identify provenance and sediment transport pathways has analysed samples from three wells: Guardian–1 and Hijinx–1 (Carnarvon Basin), and Burnside–1 (Browse Basin). Operating companies Chevron, Santos and Hess collected 3–5 kg of cuttings from sandstone bodies intersected in the three wells. Samples were sent to Geoscience Australia for zircon separation and analysis at the Geochronology Laboratory on a sensitive high-resolution ion microprobe (SHRIMP). To provide a statistically meaningful representation of ages in each sample, 70–80 grains were randomly selected for analysis. During the past 20 years, Geoscience Australia and the state geological surveys of WA, NT, Queensland and SA, together with the ANU, UWA and Curtin University, have analysed zircons found in igneous and sedimentary rocks that outcrop in WA and central Australia. This analysis has been done to determine the ages of emplacement, extrusion or maximum depositional ages. This dataset permits the ages of potential onshore provenance areas to be differentiated; hence, correlations can be made between zircons contained within the transported sands and their potential source regions from onshore Australia. In this extended abstract, the spectrum of ages in each sample will be shown, and potential provenance and sediment transport pathways will be discussed. The abstract concludes with the outline of a 2–3 year project to obtain a dataset that will provide a regional stratigraphic and spatial coverage of the North West Shelf for provenance studies.