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

Abstract

Coastal sediment transport, primarily driven by littoral drift, is a well-understood process occurring in many wave-dominated modern coasts. This transport can extend over hundreds of kilometres, linking river mouths to sand barriers and coastal dunes. Recognizing the importance of coast-parallel processes in dispersing significant sediment volumes, both source-to-sink and sediment-routing-system concepts emphasize the need to include these processes in comprehensive studies. These processes can lead to volume changes and provenance mixing within specific source-to-sink budgets and should consider sediments near the coast and on the shelf as temporary repositories before their final transit into deep-water sinks. Despite the established methodologies for studying sediment routing systems, the integration of these approaches with the geological record is limited. To address this gap, this article introduces the Coastal Sediment Routing Tract as a segment within any Sediment Routing System. The Coastal Sediment Routing Tract consists of three elements: supplier(s), storage(s) and littoral drift processes. This study presents the conceptual framework for Coastal Sediment Routing Tracts, documents an ancient Coastal Sediment Routing Tract by linking deltaic and shoreface sandstones in the Hauterivian Pilmatué Member (Neuquén Basin, Argentina) and evaluates how characterizing a single Coastal Sediment Routing Tract can refine coastal palaeogeographical reconstructions. Understanding these aspects is crucial for improving mass balance calculations in source-to-sink analyses of ancient systems.