From river to delta: down-dip changes in facies, architecture, and key stratigraphic surfaces in a low-accommodation setting

This PhD thesis is a collection of four articles that investigate the influence of a low-accommodation setting on down-dip changes in facies, architecture and key stratigraphic surfaces in fluvio-deltaic transects. The study utilizes the Cenomanian Mesa Rica Sandstone (Dakota Group), which represents contemporaneous fluvial and deltaic deposition in the Western Interior Basin. The ~400 km transect is exhumed along depositional profile, from southeast Colorado to central-east New Mexico. These excellent conditions allowed both regional-scale and high-resolution studies of key-areas. The results reveal a sand-rich end-member example of fluvial and deltaic deposition in a low-accommodation setting. The thesis emphasizes that such low-accommodation settings favour accelerated avulsion frequencies, lowered preservation potential, and formation of laterally extensive stratigraphic surfaces and sheet-like sandstone bodies. Several key stratigraphic surfaces were generated throughout a sea-level cycle, which highlights that erosion and deposition occurred contemporaneously both at regional and local scale