Delta-influenced Palaeogene depositional environments of the Frysjaodden and Hollendardalen formations in central Spitsbergen

In this study of the Central Spitsbergen Palaeogene, depositional environments and transgressive-regressive developments of the Frysjaodden and Hollendardalen formations have been reconstructed with combined evidence from sedimentary field data, geochemical parameters, and detailed analyses of benthic foraminifera. The Palaeogene succession referred to here has been deposited during the formation of a foreland basin in connection to the West Spitsbergen Orogeny. Identified lithofacies include shelf deposits of Marstranderbreen Member, followed by the progradational Hollendardalen Formation consisting of offshore transition to shoreface, foreshore, coastal marsh deposits, and transgressive sands as well as shelf deposits of the basal Gilsonryggen Member. Distal and proximal prodelta settings in Marstranderbreen shales, lagoonal deposits in upper Hollendardalen Formation and prodelta shelf deposits in basal Gilsonryggen Member could be distinguished based on biofacies analysis. The foraminiferal assemblages are entirely agglutinated and show low diversities. Their divergence from normal marine assemblages are explained partly by the regional effects of the Boreal realm, and partly by local effects of delta influence. The lowermost part of the succession consists of retrogradational parasequences, and maximum flooding occurs in the upper third of Marstranderbreen Member. The subsequent regressive development of Hollendardalen Formation is accompanied by a short parasequential episode. The coal bearing coastal marsh deposits are interpreted as the maximum regressive surfaces, while overlying transgressive sands indicate another parasequence during general relative sea level rise. Furthermore, this study locates the interval of maximum flooding in the basal Gilsonryggen Member shales. Keywords:Palaeogene, Svalbard, lithofacies, biofacies, benthic foraminifer