The evolution of major ocean basins of the world is associated with the development of characteristic assemblages of seafloor geomorphic and depositional features. We carried out a multivariate classification of ocean basins, based on an existing digital global map of seafloor features that are related to major phases of evolution according to the Wilson Cycle, namely young, mature, declining and terminal evolutionary stages. “Young” ocean basins are characterized by the absence of ocean trenches, young ocean crust (<8 MA), comparatively large areas of continental slope, thick marginal sediment accumulations, and a relatively large percent area of mid-ocean ridge rift valley (above 1.7%). “Mature” ocean basins are characterized by relatively thick marginal sediment deposits (mean thickness of 940 m), large percentage areas of continental rise (mean of 19.8%) and large areas of submarine fans (mean of 4.3%). The area of ocean trench is relatively small in all “mature” ocean basins compared with “declining” and “terminal” basins, ranging from 0 to 0.3%. A defining geomorphic feature of the “declining” category is that around 1% of their area is trench, which is more than twice the area of trenches contained in the other categories. “Declining” ocean basins contain the highest concentration of seamounts (3.5 to 5 seamounts per 100,000 km2 ), which is more than double the mean value (1.4 seamounts per 100,000 km2 ) that occurs for the “mature” category with the next highest concentration; this difference is attributed to seamount burial in Mature ocean basins. The “terminal” category of ocean basins is characterized by the greatest mean sediment thickness (4,311 m) and greatest percentage area of submarine fans (7.2%) of any ocean basin.  

Tags: geomorphology oceans