Current Status of Manganese Nodule Exploration in the German License Area

摘要

In May 2010 the German Federal Institute for Geosciences and NaturalrnResources (BGR) accomplished its third exploration cruise to thernGerman license area in the Pacific Nodule Belt. High resolutionrnbathymetry and acoustic backscatter mapping of the two subareas of thernlicense area centered at 12°N/118°W and 12.5°N/138°W has beenrncompleted during two previous cruises in 2008 and 2009. The aim ofrnthe third cruise was the eastern part of the German license area wherernwe carried out seafloor video observations and a comprehensivernsampling program. Measurements of pore water oxygen concentrationrndocument an average oxygen penetration depth of 1.5 to 2 m. Thernmanganese nodules are mainly of oxic diagenetic origin. Nodulernabundances predominantly range between 10 and 30 kg m-2 wet weightrnand change frequently within tens to hundreds of meters. In general, thernnodule abundance in terms of mass per area unit is controlled by thernsize of the nodules rather than by their number. Areas of medium tornhigh nodule abundance are dominated by large nodules and show highrnacoustic backscatter values whereas low backscatter values coincidernwith areas dominated by smaller nodules and slightly lower nodulernabundances.