The Aptian Gura Râului conglomerates (Southern Carpathians): the last remains of an extended subaqueous gravity flow deposit from the eastern flank of the Getic Nappe

Abstract

The Getic Nappe belongs to the Central Dacides or Dacia Mega Unit. Gravity flow deposits were generated by the Lower Cretaceous overthrust and uplift of this unit over the External Dacides. In the Piatra Craiului Syncline (part of the Getic Nappe), such detrital deposits are represented by the Aptian conglomerates and the uppermost Albian-Cenomanian conglomerates. Part of the infill of the syncline consists of a thick pile of NW–SE oriented conglomerates. Sedimentological study documents the presence of an association which consists of three distinct facies types, represented by: massive conglomerates; alternating conglomerates, sandstones and microconglomerates; and fining- and coarsening-upwards conglomerates. These deposits were accumulated through a series of debris flows, and hyperconcentrated or concentrated flows. The entire assemblage represents a complex routing system within submarine channels, an interpretation made by interpreting facies associations, palaeoflow directions and clast fabrics. A large part of this succession was removed by post-Albian erosion. Thus, the interpretation of the depositional system could be as a series of feeder channels or the submarine sector of a fan-delta system representing a foreland basin fill.