In between WW1 and 2 telegraph lines on the floor of the Atlantic were being snapped, by what are called turbidity currents. Scientists became aware that powerful submarine flows existed. It was likely that such turbidity became crucial at critical times in the history of the earth. Researchers, more recently, have used this information to sustain the idea of a sedimentary cycle, of epic uniformitarian proportions. The idea of course is that sand on the seashore and the continental shelf, and further out on the sea bed, has an origin in erosion from mountains, carried into the sea by rivers. This is an inexorable process unlike the alternative idea that sand can sweep out of vents on the sea floor, especially in the deep ocean, with an origin in silica within the earth. Silica is a major component of the earth – and seismic activity at vents may just allow it to accummulate in beds on the oceanic floor.
Sand may have an origin in erosion, as well as vents, a sort of compromise of the two theories. However, the link to this story waffles through some obligatory data on global warming and the possibility it may speed up the sedimentary cycle. It then alights on a catastraophic event around 50 million years ago, during the Eocene. It calls it an extreme climate change event which laid down turbidite deposits. Well, a tsunami wave from the Thera volcano laid down turbidity deposits in the Mediterranean a few thousand years ago. It seems a catastrophic event will do the same thing – very quickly. It is a prerequisite of a catastrophic event that affected the oceans. Never the less the study describes the turbidity as evidence of ‘ancient rapid submarine water currents’ which is halfway there. They then neuter it by saying it is caused by downslope transport of sediment that has accummulated at the top of the continental slope, mainly via a slow process. The rapidity is involved in the movement of the sediment down the slope from the continental margins – into deeper oceanic waters. They add that extreme weather events and a hotter climate contribute to increased erosion of the landscape which could arguably distribute sand into the deep ocean. Full article at https://doi.org/10.1038/s41598-022-27138-2 .. but PhysOrg and others also have a write up.