WEATHERING-CONTROLLED ABRASION IN THE MODERN RIO GRANDE: DOWNSTREAM FINING AND THE SEDIMENTARY RECORD OF TECTONISM

Coarse-grained "clastic wedges" along basin margins have long been considered an indicator of uplift in classic basin analysis. More recently, analysis of the interplay between accomodation space and sediment supply has shown that where tectonic uplift is accompanied by basin downwarping, increased accomodation space in the basin along the mountain front can result in a shift in coarse-grained clastic deposition away from the basin center, at least during the early stages of uplift. In the modern Rio Grande floodplain on the west side of the Rio Grande Rift, weathering-controlled abrasion may also play a role in determining the basinward extent of coarse clastics, making interpretation of tectonism even more complex.