Highlights—Crevasse Subdeltas: Small but Important

The geomorphology, stratal architecture, and sedimentologic attributes of a range of deltas have been interpreted in the context of fluvial, tidal, and wave processes and sea-level change. Most studies focus on delta-front regions, whereas finer (and typically less well exposed) delta plain deposits have received less attention. Here, Gugliotta et al. focus on defining and describing tide-influenced crevasse subdelta deposits, an important component of lower delta plain stratigraphy of a river-dominated delta in the Lajas Formation of the Neuquén Basin of Argentina. The study emphasizes the importance of understanding the relative importance of tide and river processes in facies distribution and architecture, and the applications to characterization of interdistributary deposits. The data suggest that some “tidal” deposits interpreted from the rock record may instead be river-dominated, tide-influenced crevasse subdeltas, and that this distinction has important implications for understanding paleogeography and predicting reservoir geometries.

Stratigraphic record of river-dominated crevasse subdeltas with tidal influence (Lajas Formation, Argentina) by Marcello Gugliotta, Stephen S. Flint, David M. Hodgson, and Gonzalo D. Veiga