The Gulf of Cadiz is situated geologically at the Gibraltar Arc, the westernmost arc of the Alpine- Himalayan orogenic belt. Based on extensive previous studies that include swath bathymetry, multi-channel and very hi...The Gulf of Cadiz is situated geologically at the Gibraltar Arc, the westernmost arc of the Alpine- Himalayan orogenic belt. Based on extensive previous studies that include swath bathymetry, multi-channel and very high-resolution seismic reflection, gravime- try, magnetism, heat flow probes, and underwater photography surveys, more than 500 polymetallic nodules were collected at water depths ranging from 850 to 1000 m, associated with hydrocarbon-derived carbonate chimneys, slabs, and crusts. Nodules show a wide range of sizes, densities, weights and mor- phologies. Nodules are composed of multiple milli- metre-thick layers of Fe and Mn oxyhydroxides sur- rounding a nucleus composed of Early-Middle Mio- cene plastic marls, which were expulsed from underly- ing units by fluid venting. Nodules show a high mean abundance of Fe （39.03%）, moderate Mn （5.84%）,展开更多
文摘The Gulf of Cadiz is situated geologically at the Gibraltar Arc, the westernmost arc of the Alpine- Himalayan orogenic belt. Based on extensive previous studies that include swath bathymetry, multi-channel and very high-resolution seismic reflection, gravime- try, magnetism, heat flow probes, and underwater photography surveys, more than 500 polymetallic nodules were collected at water depths ranging from 850 to 1000 m, associated with hydrocarbon-derived carbonate chimneys, slabs, and crusts. Nodules show a wide range of sizes, densities, weights and mor- phologies. Nodules are composed of multiple milli- metre-thick layers of Fe and Mn oxyhydroxides sur- rounding a nucleus composed of Early-Middle Mio- cene plastic marls, which were expulsed from underly- ing units by fluid venting. Nodules show a high mean abundance of Fe （39.03%）, moderate Mn （5.84%）,
