3-D Facies Architecture of a Fluvial-Dominated Deltaic System in the Cretaceous Ferron Notom Delta Complex

Three dimensional facies architectural studies of ancient deltaic systems are sparse in the literature even through they are highly valuable for developing 3-D quantitative models for present day systems and reservoirs. Research and correlations of a 3-D exposed outcrop in South-east Utah in the Cretaceous Notom Delta complex of the Ferron Sandstone Member was done using photomozaics and measured stratigraphic sections. The outcrop consists of three well exposed cliff faces.

The cliff faces exhibit prodelta muds, delta-front showing clinoforming geometry, and possible delta plain. Continuing research is being done to gather the extent of the complex. A total of seven measured sections were completed on all three cliff faces and have been interpreted to have 5 distinct facies. Each of the seven measured section shows a similar coarsening upward facies succession.

Internal structures of the facies include flat lamination, graded bedding, soft sediment deformation, current ripples, hummocky cross stratification (HCS), planar bedding, current ripples, wave ripples, and some cross-beds. Abundance of plant material is also found but the most notable feature is the very little to no bioturbation within these facies, other than the marine fossils in the prodelta muds.

The environment of deposition of this outcrop was in a fluvial-dominated, storm-influenced, progradational deltaic system. This interpretation is based on several measured sections and correlation of those sections. Internal structures, HCS, planar bedding, and very low bioturbation, all indicate very stressful environment possibly due to rivers in flood and storm events.