Architecture, Morphometry and Development of Subaqueous Sediment Conduits

Abstract

Canyons, channels, and gullies are incised features on the surface of the earth that act as subaqueous conduits for transferring sediment from source areas to basins. For several decades, these subaqueous sediment conduits have played an important role as storage for petroleum resources. An understanding of the architecture, morphometry, and development of these subaqueous sediment conduits in a general depositional environment will help maximize their potential. This study utilized 3D seismic reflection data obtained from various ancient subaqueous sediment conduits from fluvial, lacustrine, deltaic, and deep marine depositional environments from the Norwegian Barents Sea, offshore Israel, onshore China, and offshore New Zealand. The study aims to: 1) investigate their seismic stratigraphic architectures; 2) investigate their morphometric elements; 3) evaluate their sedimentary processes and paleoenvironments; and 4) compare their similarities and differences as well as global comparison with previous works. The results showed that isolated bright amplitudes with incised surfaces were characteristic of these subaqueous sediment conduits, while most of the conduits had morphometric elements, such as thalwegs, walls (including terraces), overspill points or levees, and flanks. These architectural and morphometric elements showed that gravity flow is dominant in subaqueous sediment conduits in the lacustrine and marine environments, and traction currents were observed in the subaqueous sediment conduits in the fluvial environments, as well as river-dominated deltas (minor marine influences). Furthermore, the subaqueous sediment conduits were similar with respect to the existence of incised surfaces and morphometric elements; however, their sedimentary processes, tectonics, climates (including latitudinal controls), and paleoenvironments were different. This research demonstrated that a comprehensive study of all depositional environments and the utilization of cutting-edge techniques for advanced seismic interpretations (quantitative seismic geomorphology, in particular) are necessary to appropriately interpret the sedimentary processes and paleoenvironments that lead to improved petroleum resources utilization.