Documenting a coastal sediment routing tract in the sedimentary record: implications for coastal paleogeography and sand distribution patterns

Abstract

Coastal sediment transport, primarily driven by littoral drift, is a well-understoodprocess occurring in many wave-dominated modern coasts. This transport can extend overhundreds of kilometres, linking river mouths to sand barriers and coastal dunes. Recognizingthe importance of coast-parallel processes in moving significant sediment volumes, bothsource-to-sink and sediment-routing-system concepts have emphasized the need to include theseprocesses in comprehensive studies. These processes can lead to volume changes andprovenance mixing within specific source-to-sink budgets and should consider sediments nearthe coast and on the shelf as temporary repositories before their final transit into deep-watersinks. Despite the established methodologies for studying sediment routing systems, theintegration of these approaches with the geological record is limited. To address this gap, weintroduce the Coastal Sediment Routing Tract (CSRT) as a segment within any SedimentRouting System. The CSRT consists of three elements: supplier/s, storage/s, and littoral driftprocesses. This contribution will: a) present the conceptual framework for CSRTs, b) documentan ancient CSRT by linking deltaic and shoreface sandstones in the Hauterivian PilmatuéMember (Neuquén Basin, Argentina), and c) evaluate how characterizing a single CSRT canrefine coastal paleogeographic reconstructions. Understanding these aspects is crucial forimproving mass balance calculations in source-to-sink analyses of ancient systems.