Young Volcanism on 20 Million Year Old Seafloor: The DISCOL Area, Nazca Plate

Devey, Colin W., Boetius, Antje, Kwasnitschka, Tom, Augustin, Nico, Yeo, Isobel A. and Greinert, Jens (2016) Young Volcanism on 20 Million Year Old Seafloor: The DISCOL Area, Nazca Plate [Talk] In: AGU Fall Meeting 2016, 12.-16.12.2016, San Francisco, USA.

Full text not available from this repository.

Abstract

Volcanism in the ocean basins is traditionally assumed to occur only at the plate margins (mid-ocean ridges, subduction zones, possibly also transform boundaries) and areas of intraplate hotspot activity related to thermal plumes in the mantle. As a result, abyssal areas away from hotspots are seldom explored systematically for signs of volcanism and are generally regarded as volcanically "dead". Here we present serendipitous results from the Peru Basin, a site of Mn-nodule accumulation which was targetted in 1989 for a large-scale disturbance experiment (the DISCOL experiment) to simulate the effects of seabed nodule mining. The area is truly intraplate - it is 700 km from the south American subduction zone or the Galapagos Islands and 2000 km from the East Pacific Rise. A return trip to DISCOL in 2015 to assess the extent of environmental recovery also included a remotely-operated underwater vehicle (ROV) dive on a small (300m high) seamount adjacent to the Mn-nodule field. ROV video records show the seamount is generally heavily sedimented but has a small (100x150m) pillow mound and an area of indurated calcareous sediments apparently cut by basaltic dykes near its summit. The summit is also cut by N-S and E-W-trending faults, some with up to 20m of throw, whose scarps expose thick sedimentary sequences. The virtual absence of sediment covering the pillows or dyke outcrops suggest that they are very recent - the thick sediment pile exposed on the fault scarps suggests that they were erupted on top of an old seamount. Regionally, acoustic data (bathymetry and backscatter from the ship-mounted multibeam system) shows several other seamounts in the region which may have experienced recent volcanic activity, although no sign of a linear volcanic chain is seen. Taken together, these observations suggest that, even at age 20Ma, the Nazca Plate is volcanically active.

Document Type: Conference or Workshop Item (Talk)
Additional Information: OS41C-1983
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS Magmatic and Hydrothermal Systems
Date Deposited: 10 Apr 2017 10:03
Last Modified: 10 Apr 2017 10:03
URI: http://eprints.uni-kiel.de/id/eprint/37131

Actions (login required)

View Item View Item