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TitleMarine geology
AuthorPiper, D J WORCID logo; Normandeau, AORCID logo
SourceEncyclopedia of geology, volume 6; by Alderton, D (ed.); Elias, S A (ed.); Earth Systems and Environmental Sciences 2020 p. 327-341,
Alt SeriesNatural Resources Canada, Contribution Series 20200152
Mediapaper; on-line; digital
File formatpdf
Subjectsmarine geology; surficial geology/geomorphology; environmental geology; Science and Technology; Nature and Environment; Society and Culture; depositional environment; sedimentary environment; marine environments; coastal environment; oceanography; crustal studies; bedrock geology; marine sediments; bathymetry; mapping techniques; cumulative effects; Climate change
Illustrationslocation maps; geoscientific sketch maps; cross-sections; photographs; time series; bar graphs; pie charts; 3-D images
ProgramMarine Geoscience for Marine Spatial Planning
Released2020 12 02
The geology of the marine realm is fundamentally different from that of the continents. Marine geology requires specialized instrumentation, mostly deployed from ships, including acoustic devices for imaging the seabed and its subsurface geology. Seabed samples are collected using remotely operated tethered vehicles, corers and light drills, but samples deeper than 20 m require a dedicated drillship. Oceanic crust underlies 60% of Earth's surface in the ocean basins. Their major bathymetric features are controlled by cooling of lithosphere away from spreading ridges, enhanced melt production in hot spots and the effects of subduction at trenches. Some 80% of oceanic crust is blanketed by pelagic sediments of biogenic carbonate and silica, and wind-blown abyssal red clays. Thinned continental crust underlies most continental margins and marginal seas. Margins comprise three main physiographic regions, where different sediment transport processes operate. The continental shelf is the shallow-water extension of the land surface, affected by waves, tides and sediment input directly from rivers. The steep continental slope separates the shelf from the deep ocean and is characterized by submarine canyons and large landslides, which supply shelf sediment to the continental rise by turbidity currents. On the rise, these currents build deep-sea fans, abyssal plains and fill some subduction trenches with terrigenous sediment. Oceanic circulation on the slope and rise reworks terrigenous sediments into contourite drifts. Landslides and currents are hazards to electricity and telecommunication cables and petroleum installations. Global climate change will result in rising sea level and disruptions of the oceanic carbon cycle.
Summary(Plain Language Summary, not published)
This article presents a overview of the field of marine geology

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