Permian-Triassic sedimentology of Jameson Land, East Greenland; incised submarine channels in an anoxic basin

The presence of deeply erosive, conglomeratic sandstone-filled channels around the Permian-Triassic (P-Tr) boundary in East Greenland has been widely cited as evidence for a major, late Permian eustatic lowstand. Facies analysis of such channels and their associated strata in fact suggests that they record part of an intrinsic style of basinal deposition (that persisted into Early Triassic time). Their origin can be explained without the need to invoke eustatic sea-level fall. Active faulting and hinterland elevation is envisaged to have generated powerful sediment-gravity flows that were capable of submarine erosion of fine-grained, unconsolidated strata. Stacked, turbidite-sandstone-filled lenses also occur beneath fan delta sandbodies and probably record infill of channels or chutes cut into the subaqueous slopes of such deltas. Shale successions developed between the incised channel locations record complete P-Tr transitions in which a rapid onset of anoxic deposition is seen in latest Permian time. This is the local manifestation of a global anoxic event. Unusual aspects of the Lower Triassic sequence in Greenland include the presence of well-oxygenated intervals, stromatolite bioherms and red algae.