<p>The Triassic sedimentary succession in the Central North Sea has been investigated to establish a broader understanding of
the Triassic Period, from the combined interpretation of seismic reflection data and well data. The Triassic succession has
been subdivided into four seismic units, where unit boundaries are characterized by regional seismic amplitude anomalies,
reflecting changes in gross sedimentary facies or rock properties. A successful correlation between sedimentary facies, interpreted
within the well sections and distinct seismic reflection patterns, allowed a thorough mapping of the gross palaeoenvironment
throughout the Triassic. The method presented of subdividing a continental sedimentary succession into seismic units should
be applicable elsewhere in other basins. The main source area during the Triassic was Scandinavia to the north, and sediment
transportation was mainly along north–south- and NE–SW-trending lineaments, which are at present located onshore southern
Norway, and in the Åsta Graben and the Varnes Graben offshore. An uplifted Skagerrak Graben area acted as source area in the
Early and early Middle Triassic, with sediment dispersal to the south and SW. High relief existed for a longer period in western
Scandinavia than in eastern Scandinavia, which supports an asymmetric shape of the Scandinavian mountains during the Triassic.
Accommodation space in the Early Triassic was mainly controlled by the relief inherited from a Late Carboniferous–Permian
rift phase. Although thermally induced regional subsidence continued in the Middle and Late Triassic, creation of local accommodation
space was mainly limited to halokinesis, including redistribution and withdrawal of salt from the subsurface. The Upper Triassic
succession is eroded across the western and central parts of the study area, although the Upper Triassic unit is preserved
in synforms adjacent to salt structures. In the western part of the study area, dry, playa conditions prevailed during the
Early Triassic, although fluvial systems supplied long-transported sandy detritus southeastwards in the late Early Triassic.
More sandy detritus was transported into the sedimentary basin in the Middle and Late Triassic, concurrently with a gradually
wetter climate.
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