A database solution for the quantitative characterisation and comparison of deep-marine siliciclastic depositional systems

In sedimentological investigations, the ability to conduct comparative analyses between deep-marine depositional systems is hindered by the wide variety in methods of data collection, scales of observation, resolution, classification approaches and terminology. A relational database, the Deep-Marine Architecture Knowledge Store (DMAKS), has been developed to facilitate such analyses, through the integration of deep-marine sedimentological data collated to a common standard. DMAKS hosts data on siliciclastic deep-marine system boundary conditions, and on architectural and facies properties, including spatial, temporal and hierarchical relationships between units at multiple scales. DMAKS has been devised to include original and literature-derived data from studies of the modern sea-floor, and from ancient successions studied in the sub-surface and in outcrop. The database can be used as a research tool in both pure and applied science, allowing the quantitative characterisation of deep-marine systems. The ability to synthesise data from several case studies and to filter outputs on multiple parameters that describe the depositional systems and their controlling factors enables evaluation of the degree to which certain controls affect sedimentary architectures, thereby testing the validity of existing models. In applied contexts, DMAKS aids the selection and application of geological analogues to hydrocarbon reservoirs, and permits the development of predictive models of reservoir characteristics that account for geological uncertainty. To demonstrate the breadth of research applications, example outputs are presented on: (i) the characterisation of channel geometries, (ii) the hierarchical organisation of channelised and terminal deposits, (iii) temporal trends in the deposition of terminal lobes, (iv) scaling relationships between adjacent channel and levee architectural elements, (v) quantification of the likely occurrence of elements of different types as a function of the lateral distance away from an element of known type, (vi) proportions and transition statistics of facies in elements and beds, (vii) variability in net-to-gross ratios among element types

Database-informed analysis of sedimentary systems at the marine shelf-to-slope transition

Submarine canyons and shelf-edge deltas are important elements of continental margins, which influence sediment transport dynamics across shelves and slopes to deep-water basins, and the storage of sediment. However, the factors that control their evolution and their relative importance remain poorly understood. Via three separate metastudies this thesis presents a quantitative, global study of submarine canyons and shelf-edge deltas in the context of (i) their physiographic setting, (ii) their associated source-to-sink (S2S) system, and (iii) their environmental setting, resulting in a novel quantitative characterisation of submarine canyons and shelf-edge deltas. The principal findings of this project are as follows: (i) Overall, scaling relationships of submarine canyons and shelf-edge deltas with descriptors of their physiographic setting and environment are weak, which reflects the complex influence of multiple factors, both allogenic and autogenic, on their geomorphologies, and how these factors might amplify, weaken or overprint a scaling relationship. (ii) Despite the complex and variable geomorphologies demonstrated for studied examples of submarine canyons and shelf-edge deltas, some morphometric attributes of both sedimentary system types do differ between environmental settings, indicating a greater genetic influence of certain individual environmental variables over others. (iii) Moderate and strong scaling of morphometric attributes in submarine canyons and shelf-edge deltas with each other, and with variables of the physiographic setting and associated S2S system, suggest that the geomorphologies of submarine canyons and shelf-edge deltas can be predicted to some degree, based on knowledge of their environmental setting, and vice versa. The findings from this project help to clarify the complex influence of multiple factors on the geomorphologies of submarine canyons and shelf-edge deltas, providing a framework for the prediction of their geomorphologic characteristics across environmental settings and for the integration of submarine canyons and shelf-edge deltas into S2S system analyses