Alluvial architecture of fluvio-deltaic successions: a reviewwith special reference to Holocene settings

Abstract

Alluvial architecture has been subject of many studies because of theoccurrence of natural resources in ancient fluvial successions. This paperprovides an overview of the current state of research on alluvialarchitecture with special reference to Holocene fluvio-deltaic settings.Several examples from modern fluvio-deltaic areas, especially the HoloceneRhine-Meuse delta (the Netherlands) and the Lower Mississippi Valley(U.S.A.), are used to illustrate the architectural elements that can bedistinguished in fluvial successions and to show the influence of thevarious controls on alluvial architecture (base level, climate, tectonism,aggradation, avulsion, and compaction). Avulsion is regarded as a principalprocess in the formation of fluvio-deltaic sequences, because it determinesthe location and number of active channels on the floodplain. The avulsionmechanism is still subject of debate, though. A brief description of theevolution of process-based alluvial-architecture models is given. Thesemodels simulate the proportion and distribution of coarse-grained channelbelts in fine-grained overbank deposits. The major drawback of thepresent-day alluvial-architecture models is the lack of (three-dimensional)quantitative field data to test and validate them. The paper concludes withthe suggestion to collect more architectural data from natural fluvialsettings, to improve simulation of channel-belt geometry inalluvial-architecture models, and to implement new data and knowledge offluvial processes into models.