Deep-sea current evidence from abyssal sediments

摘要: Abstract Relatively strong bottom currents in the deep-sea can be inferred from sedimentary structures observed photographs and cores. The majority of high steep topographic prominences, such as seamounts, escarpments crests major ridges, show ripples, scour rock outcrops. Although photographic current evidence is uncommon deeper waters ocean basin floor, striking significant examples do occur. Current ripples are beneath Antarctic western South Atlantic, below Gulf Stream Florida Straits on Blake Plateau, outflowing Mediterranean water west Gibraltar deep Drake Passage. three types sands silts turbidite, accretionary, residual. latter two always associated with some areas turbidites reworked by currents. Traction velocities necessary for transport sediment particles probably range 4–60 cm/sec, similar to those found through dynamic computations geostrophic recent direct measurements.