SOME OTHER SINKS AND THEIR IMPLICATIONS FOR SEDIMENT ROUTING (Invited Presentation)

Detrital zircon source-to-sink studies have typically emphasized continent-scale contributive fluvial systems, which in most cases feed submarine fans at the toes of passive margins. In addition to these contributive fluvial systems (CFS), there are other types of high-volume sediment sinks for which provenance studies can provide considerable leverage in assessment of regional sediment delivery. They include deposits of (2) distributive fluvial systems (DFS), (3) large axial-fluvial systems (AFS), and (4) redistributed sediment systems (RSS). Type 4 RSS consist of extensive eolian and associated depositional systems, known from backarc regions, basins associated with intracratonic deformation, and distal foreland settings. Although scale varies, AFS and RSS can record continent-scale drainage systems, whereas type 2 DFS tend to receive sediment from adjacent orogens. Examples of DFS include parts of the Wahweap and correlative sandstones of the Cretaceous Western Interior basin; examples of AFS are Late Cretaceous axial drainages of the Western Interior. Detrital zircon data can be critical in discriminating DFS and AFS. Examples of RSS include the Pennsylvanian-Permian and Jurassic ergs of the Colorado Plateau and the Recent ergs of the Rub' al Khali.

In the case of DFS and AFS, important sandy sinks lie along the sediment-transport route, whereas in CFS and RSS models, the big volume sandstones are commonly at the end of a transcontinental sediment delivery network with little preservation potential in the stratigraphic record. Nevertheless, the four system types can combine to create linked sinks along sediment-transport routes, for example AFS linked to terminal submarine fan systems, as in the example of the linked Gangetic foreland and Bengal submarine fan. Detrital zircon data and petrographic provenance methods offer a means of interpreting composite sink assemblages.