Avulsion and its implications for fluvial-deltaic architecture: insights from the Holocene Rhine-Meuse delta

Abstract

Avulsion is a key process in the formation of fluvial-deltaic successions and a primary control on deltaic architecture. It determines the distribution of sediment and water and hence which location in the delta receives clastic sedimentation for what time. This makes the avulsion process an autogenic control on channel network configuration (‘connectedness’) and recurrence of channel belts (‘channel deposit proportion’) in deltaic successions. To be able to predict and understand the architecture and facies distribution in deltaic deposits with confidence, their formative processes need to be considered over a range of time and spatial scales. The Holocene Rhine-Meuse delta in the Netherlands offers a unique opportunity to study delta development and resulting deltaic successions at millennial and sub-millennial time resolution over the last 9000 years. The deltaic deposits have been studied extensively from apex to tidal river mouth (Fig. 1). The complete coverage resulted in detailed reconstructions of the Holocene palaeogeographic development (Berendsen & Stouthamer 2000, 2001), avulsion history (Stouthamer & Berendsen 2000; Stouthamer 2001), growth and occupancy of accommodation space (Cohen 2005; Erkens 2009) and alluvial architecture (Gouw & Erkens 2007; Gouw 2008; Hijma et al. 2009; Hijma 2009). The accumulated results allow to study the relationships between avulsion and deltaic architecture.