Sedimentary Structures and Textures of Rio Orinoco Channel Sands, Venezuela and Colombia

摘要

Sedimentary structures and textures of Rio Orinoco channel sands in Venezuela were studied during March 1983, when the river was at low stage. The project was conducted as one of a series of studies on hydrology, water chemistry, and other aspects of the Rio Orinoco. Most sedimentary structures represented in sand bodies of the Rio Orinoco are tabular-planar cross-strata which, together with some wedge-planar cross-strata, are the products of sand-wave deposition. At a few localities, sets of nearly horizontal strata occur between tabular-planar sets and are interpreted to be the deposits of very fast currents of the upper flow regime. The river channel sands were determined to be largely moderately well sorted.