Triassic sediment dispersal patterns and their implications for the De Geerdalen Formation as an analogue for the southwest Barents Shelf

The Triassic on the Barents Shelf is thought to have complex sediment dispersal patterns (Fleming et al., 2015; Fleming et al., 2014; Flowerdew et al., 2015; Scott et al., 2012). Whilst northern Scandinavia and Greenland are known to have been important source areas in the Mesozoic, insights from wellbores and seismic surveys have revealed that a major deltaic system associated with the uplift of the Uralian Mountains spread northwest across the Barents shelf and controlled sand dispersal patterns in the Triassic. Recently, these systems have been shown to have reached as far as western Spitsbergen (Bue and Andresen, 2013).

On the SW Barents Shelf, these systems resulted in thick accumulations of sediment, laid down in predominantly deltaic and shallow-marine environments. Here, utilising a range of provenance techniques, including petrographic data, heavy mineral abundance counts, mineral geochemistry, Pb isotopes in K feldspar and detrital zircon, apatite and rutile U-Pb geochronology in combination with sedimentology and analysis of published seismic interpretations, we can accurately delineate between the different source areas.

The De Geerdalen Formation in Svalbard often used as an analogue for Triassic Sedimentation on the SW Barents shelf (e.g. Klausen, 2013; Lord et al., 2014), provenance analysis reveals distinct differences exist between the two areas. These results raise concerns over the current thinking of dominant SE-NW sediment transport in the Triassic. In addition, results have important implications for those using the De Geerdalen Formation in Svalbard as an analogue to the SW Barents Sea.