Dropstones in the Mar del Plata Canyon Area (SW Atlantic): Evidence for Provenance, Transport, Distribution, and Oceanographic Implications

A variety of gravel- to cobble-sized rocks, recovered from the Mar del Plata (MdP) Canyon area (Western South Atlantic at 38°S) and interpreted as ice-rafted debris, represent first evidence that large icebergs have floated in Falkland (Malvinas) Current southern polar high latitudes far northward. Detailed petrographic analyses identified Antarctic Peninsula, sub-Antarctic islands Scotia Sea, Tierra Fuego plausible source areas. The drift process could started early beginning last deglaciation, according an age obtained a cold-water coral fragment associated with one dropstones. At end Last Glacial Maximum, been supplied Circumpolar Current, captured by those ocean current branches circumvent Islands entered Argentine Margin. When iceberg fleets approached Brazil-Falkland Confluence Zone its steep latitudinal temperature gradient, got oceanographically trapped melted off rapidly. sediment load sinking down seafloor formed dropstone blanket particularly where MdP had incised into continental slope. Here, mass-flow processes, induced local slope instability, along-slope resorting, due erosional effects strong persistent contouritic bottom currents, favored enrichment dropstones form loose, coarse drape inside morphological depressions. velocity would be locally enough rework this sediment, leaving rafted debris lag deposit.