Geometrical analysis of deltaic clinoforms and their implication for sediment infill and sea-level conditions in Sørvestsnaget Basin, southwestern Barents Sea.
MetadataShow full item record
Clinoforms can develop in different environments and with different morphologies. Variation in the height, slope gradient and length is one of the methods to differentiate clinoforms. It also helps in evaluating the environment to which clinoforms belong. The most comprehensive tool to calculate different clinoform parameters is the identification of clinoforms constructive points such as, head, upper rollover, lower rollover, and toe points. The Late Eocene deltaic clinoforms in the Sørvestnaget Basin, SW Barents Sea have been studied using 200 km2 of two dimensional seismic reflection data. Seismic attribute analysis include the use of instantaneous phase to identify morphological component of the clinoforms. The estimated clinoform parameters include height, slope gradient, relief element and shape ratio. These parameters were used to understand the variation in sea-level conditions and sediment infill into the basin. To restore the clinoforms to their depositional morphology, the base units and the Upper Regional Unconformity, which corresponds to the upper part of the clinoforms were flattened. Flattening of these horizons allowed easy estimate of the clinoform parameters and trajectory analysis.The clinoforms in the study area are part of a shallow marine delta that has prograded from the earliest NE portion to the SW part of the Sørvestsnaget Basin. The clinoforms have an average height of 229 m and angle of dip of 020 to 060. The most inclined portion, which relates to delta front deposits of the delta is indicated with an average foreset slope gradient of ~040. Erosion as a result of episodic local progradation and retreating of beds have exposed the delta plain and prodelta portions of the clinoforms. Sea level conditions in the Sørvestnaget Basin have been examined by recognition of upper rollover points of clinoforms. The studied delta was formed during sea level stillstand and sea level rise, which is mainly reflected as ascending trajectory style. The shoreline trajectory shows that sea level fluctuation happened at a high rate as is common with shallow marine deltaic environments. The shoreline break position has moved from about 2,330 to 10, 010 m.The Late Eocene deltaic clinoforms in the Sørvestsnaget Basin may form good hydrocarbon reservoirs and are analogue to the Jurassic Bridport Sand in the South UK and Sognefjord Formation in the North Sea.