A Potential Source For the Early Cretaceous Barents Sea Sink Through Discharge Estimations Of the Fluvial Festningen Sandstone In Svalbard, Norway

Abstract

The depositional model of the Festningen Member of the Barremian Helvetiafjellet Formation is that fluvial to inner deltaic-plain conditions were established as deltas built southeastward into the Barents Sea basin from an unknown source northwest of present-day Svalbard. Evidence for a large artic drainage basin into the Cretaceous Barents Sea is suggested by using established scaling relationships and the fulcrum method in the Festningen Sandstone.

Data from several locations in Svalbard: Konusdalen, Revneset, Criocerasaksla, and Hanaskogdalen. The sections were all initially photographed by drone in order to determine channel body dimensions and architecture as well as to record data for 3D photogrammetric construction of virtual outcrop models. Paleohydraulic estimates based on the fulcrum method use bankfull channel dimensions, specifically the height and width, and the D16, D50, D84, and D90 grainsizes to develop basin-process models and infer past catchment constraints. Festningen Sandstone sections were logged and found to represent braided fluvial systems with mid-channel bars up to 3 m thick and channel-fills up to 4 m thick. The coarse grainsize and large clasts, frequently 3-4cm and up to 15cm in diameter, in the samples show that this was a large river capable of moving a coarse bedload. Scaling relationships equivalent to 4 m channels and coarse grained D-values is on the order of the modern braided Missouri River near the South Dakota/Nebraska border.

The Bjarmeland Platform in the western Barents Sea have a potential petroleum play in the Lower Cretaceous strata, which are, in part, considered to have been fed by the same Festningen fluvial system that is represented in cliff sections on Svalbard. Seismic profiles show clinoforms that may suggest deltaic facies, but remains unknown due to lack of well data.

Seismic data shows that the Cretaceous Festningen fluvial system was able to deliver enough sediments into the basin to build clinoforms. The size of the source area sufficient to produce a trunk river on this scale remains unconstrained, but an area of at least 500,000 km2 is necessary to produce the river found in the rock record. Existing Arctic tectonic reconstructions do not consistently show a land area of sufficient size to accommodate this magnitude of drainage area, but results from this study may provide further input to the discussion on timing and land-mass configuration in the present day arctic during the Early Cretaceous.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018