Submarine slide blocks and associated soft-sediment deformation in deep-water basins: A review

Three-dimensional (3D) seismic and outcrop data are used to review the significance of submarine slide blocks and associated soft-sediment deformation structures in deep-water basins. Submarine slide blocks are generated during major instability events in a variety of geological settings and their size exceeds that of boulders, which are <4.1 m. Slide blocks can be similar to 500 m high by >4.5 km long on a number of continental margins, presenting internal folding, thrusting and rolling over basal breccia-conglomerate carpets. In addition, soft-sediment deformation structures such as foliated strata, intrafolial folds, tiling, bookshelf sliding and dilational jogs reflect important shearing within blocks and their basal glide planes. This work proposes that buried blocks and associated coarse-grained debrites are capable of forming prolific reservoir intervals for hydrocarbons and mineralization. Three-dimensional leakage factor models show the bulk of fluid flow to be focused in vertical and horizontal surfaces within, and immediately below displaced blocks. The generation of large slide blocks can also mark the sudden release of overburden pressure, and result in the loss of seal competence above existing hydrocarbon fields. Ultimately, this review clarifies the present-day understanding on the modes of formation of submarine slide blocks, confirming their economic importance in deep-water basins throughout the world. (C) 2015 The Author. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).