Overview

This module deals with the cascade from source to sink, divided up in to three segments: catchment-fluvial, coastal (continental shelf), and deep marine (Sømme et al., 2009). Each segment is a morphodynamic zone, but these zones are also genetically related and dynamically connected (Allen, 2017). Geomorphology, sedimentology, and stratigraphy are core to understanding the flow of sediments within and through these segments. Sediments from single or multiple sources are routed through the source to sink cascade, with each morphodynamical zone connecting regions of erosion, sediment transfer, temporary storage, and long-term deposition.

The module will explore the key foundational and conceptual frameworks (thresholds, sensitivity, drivers) in these geomorphological zones. The module will explore the mechanisms and responses to external factors, such as environmental change, tectonics, base-level change, and anthropogenic activity, alongside developing an understanding of intrinsic and extrinsic processes in these key zones. The module will examine sediments within these zones, which are important components of biogeochemical and ecological systems, and have major socio-economic significance. This module will examine the sediment routing system (origin, controls, and processes that determine the properties, transport, and deposition) in the catchment-fluvial, coastal (e.g., beaches, barriers, deltas, tidal flats) and continental shelf, the deep ocean basins segments. Students will be encouraged to critically engage with the literature and key debates, and to develop a scholarly and applied approach to the subject.

Major themes covered

Foundation and Framework: Equilibrium, thresholds, transition, complexity, and response. External/Intrinsic Drivers (Base level change, Climate, Tectonics, Humans).

Catchment-Fluvial Environments: Geomorphology Single (meandering) and multi-thread (braided, wandering) channels Alluvial channels, bars and floodplains Facies, sedimentary sequences, and subenvironments Importance of river to marine cascade Cable Bay as natural laboratory Pilcomayo case study & Ebro/Rhone/Var case study Alluvial Histories River response to environmental change Quaternary fluvial history

Coastal-Beach Environments: The coastal morphodynamic system Coastal classification: transgressive/progressive; wave/tide dominated Coastal barrier systems and the shoreface Beaches: classification, wave-driven currents, morphology, engineering applications Tidal flats

Deltaic Environments: Classification: wave/fluvial dominance Stratigraphy Continental shelf : Classification: tide/wave/storm dominated Morphological features Sediment budgets

Shelf edge and Deep Marine Environments: Processes, facies, sedimentary sequences, and subenvironments Density cascading Sediment gravity flows Submarine fans and channels and hydrocarbons Contourite drifts Pelagic and hemipelagic sedimentation

Learning Outcomes

• Demonstrate knowledge of the key concepts governing fluvial behaviour in a catchment. Understand the concepts and principles which govern marine sedimentary environments (ES 3.3.4.1)

• Explain the features of ancient and modern braided and meandering river systems and sedimentary sequences.

• Reconstruct ancient sediment environments using data gathered through field observation

• Synthesise and summarise interdisciplinary information critically (ES 3.3.4.2), and critically analyse the literature.

• Understand how an interdisciplinary approach is needed to understand the nature of sediment deposits (ES 3.2.1.1)

• Understand physical and key biological controls of sedimentation in coastal and shelf seas, and deep sea environments, and the temporal and spatial scales of variation, and anthropogenic impacts (ES 3.2.1.2)

• Understand the long-term dynamics of river systems and the controls operating within fluvial systems, and be able to comprehensively discuss how these condition river response to environmental change.