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The Middle to Upper Triassic series in the Norwegian Barents Sea represents an important target for hydrocarbon exploration. However, the dating and correlation of these rocks are problematic due to the scarcity of age-diagnostic macrofossils, lateral facies variation and the overall thickness of the succession. Palynology has proven to be a useful dating tool but further work is necessary to improve the zonal resolution, particularly for the Upper Triassic Series. The current paper presents a detailed palynostratigraphy of the Middle – Upper Triassic succession in four exploration wells (7120/12-2, 7228/2-1s, 7-1a and 9-1s) drilled in the Hammerfest and Nordkapp basins. Eleven informal palynological zones are described from the stratigraphic interval spanning the Kobbe, Snadd and Fruholmen formations, which constitute regionally significant hydrocarbon source and reservoir rock facies. The results of this study contribute to a higher resolution palynostratigraphy for the Middle to Upper Triassic strata of the southern Barents Sea (SBS), and an improved correlation with the stratigraphy of the Svalbard Archipelago. Palynofacies data for the succession, presented here for the first time, indicates depositional environments ranging from fluvio-deltaic to offshore marine. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents palynological evidence from the late Early Triassic (late Smithian) to the Late Triassic (Rhaetian) of the Barents Sea area: A continuous palynological succession from an exploration well (7228/7-1A) in the Nordkapp Basin (SW Barents Sea) and palynological data from a series of shallow cores drilled at the Svalis Dome (Central Barents Sea) representing selected Triassic intervals. These fully marine sediments are independently dated by marine faunas. Both records show significant shifts in the distribution of the main floral elements. Changing ratios of spore-pollen taxa, grouped as hygrophytes versus xerophytes and spores versus pollen, reveal major changes of the floras within the studied interval. One distinct turnover coincides with the Smithian/Spathian boundary where lycopsid and pteridophyte spores dominated assemblages change to pollen (pteridosperms and conifers) dominated assemblages. Lower Middle Triassic assemblages are again dominated by lycopsid spores while the assemblages from the upper part of the Middle Triassic and the lower part of the Late Triassic are characterised by dominance of coniferous pollen and show the decline of pteridosperms. In the latest Triassic fern spores are abundant and diverse. In contrast to the Middle Triassic the pollen assemblages are characterized by cycadophytes and Araucariacites. These distribution patterns are interpreted to reflect climatic changes. The presented results from Norwegian Boreal areas confirm the significant differences between quantitative distribution of specific taxa as well as diversity of major groups in plant assemblages from low and mid latitudes. The present survey opens new perspectives for more detailed comparisons and climatic interpretations of floras from the Triassic period, a time during which Mesozoic vegetation established. The major changes in the dominance of specific floral elements, especially the diversification and spreading of the conifers, can probably be related to climatic changes. [Copyright &y& Elsevier]

Four stratigraphic cores (7533/2-U-1, 2-U-2, 3-U-7 and 7534/4-U-1) drilled in the Sentralbanken High provide important reference sections for the Upper Triassic succession in the northern Barents Sea. The cores span the De Geerdalen, Flatsalen and Svenskøya formations (Kapp Toscana Group), which are equivalent to the Snadd to middle Fruholmen formations of the southern Barents Sea. Only cursory palynological study of the cores has been conducted previously, and no published palynofacies data is available. We present a detailed palynostratigraphy from the cores, and describe six informal palynological assemblages. Comparison with independently dated sections from elsewhere in the region enables a revised age interpretation of early Carnian to Norian for the cored interval, thereby improving correlation between Sentralbanken, Svalbard and the southern Barents Sea. A dominance of amorphous organic matter (AOM) and marine palynomorphs indicates a distal suboxic-anoxic marine depositional environment for the lower De Geerdalen Formation, with an abrupt change to a nearshore marine environment above an erosion surface in core 7534/4-U-1. Palynofacies from the remainder of the formation are characterised by a dominance of phytoclasts and are interpreted as indicative of a delta front to coastal plain environment. The reappearance of AOM, microforaminiferal test linings and marine microphytoplankton in the Flatsalen Formation in cores 7533/2-U-1 and 2-U-2 reflects a regional transgression of early Norian age. Reworked palynomorphs, shale rip-up clasts and a transition to phytoclast-dominated palynofacies above an erosion surface at the base of the overlying Svenskøya Formation is consistent with a disconformity, which was previously identified as a possible sequence boundary on the neighbouring island of Hopen. [ABSTRACT FROM AUTHOR]

Nine palynological intervals, A-I in ascending order, are recognised in the Carboniferous succession of the well 7120/2-1 on the Loppa High in the western Barents Sea.Within the Billefjorden Group intervals A-E are correlated with the early Viséan to Serpukhovian Pu to TK Miospore Zones of western Europe. The known sedimentation break between the Billefjorden and Gipsdalen groups occurred in the Serpukhovian, as interval G of the lower part of the Gipsdalen Group is equivalent to the late Serpukhovian SO Miospore Zone. Lycospora pusilla and Densosporites spp. dominate these assemblages, indicating humid conditions. The topmost interval I correlates with early Moscovian palynofloras of the Arctic. It is at the oldest equivalent with the NJ Miospore Zone. Assemblages within this interval are dominated by the monosaccate pollen Florinites and Potonieisporites, with abundant taeniate and non-taeniate bisaccate pollen, indicating deposition under a dry climatic regime. [ABSTRACT FROM AUTHOR]