Manganese Nodules
Tuesday, 8. September 2009, 07:58:37
Manganese nodules were first discovered on the ocean floor in 1803. Manganese nodules, are rock concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core or nucleus. Nodules lie on the seabed sediment, often partly or completely buried. They vary greatly in abundance, in some cases touching one another and covering more than 70 per cent of the bottom. They may contain up to 70% manganese, around 15% iron, and further some copper, cobalt, zinc and nickel in small proportions.
Nodule growth is extremely slow – on the order of a centimeter over several million years. Several processes are involved in the formation of nodules, including the precipitation of metals from seawater (hydrogenous), the remobilization of manganese in the water column (diagenetic), the derivation of metals from hot springs associated with volcanic activity (hydrothermal), the decomposition of basaltic debris by seawater (halmyrolitic) and the precipitation of metal hydroxides through the activity of microorganisms (biogenic). Several of these processes may operate concurrently or they may follow one another during the formation of a nodule.
Since the 1960's manganese nodules have been recognized as a potential ore source. Germany seems finally willing to do something serious about it.
Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) in Hannover, Germany, has from the International Seabed Authority received an exploration licence for 15 years in 75.000 km2 sea-bed of the Pacific Ocean between Mexico and Hawaii - in the Pacific Nodule Belt between the Clarion and Clipperton fracture zones.
German geologists recently carried out an extended research project in the Pacific. They wanted to find out how many manganese nodules there are, and where they are scattered. 24 million tons of precious metals are believed to be lying under the world’s oceans. The German geologists are trying to learn whether the nodules could be recovered from the seabed without damaging the environment, and which technology would be best suited to do that.
The Pacific nodules contain on average 15-30% manganese, 7-15% iron, 1,2% nickel, 1% copper and 0,3% cobalt. They can have a diameter of up to 50 cm and are mainly found at a depth of 4-5 km. Together they may contain thousands of billions of tons manganese.
The area between the Clarion and Clipperton fracture zones and the areas belonging to different contractors are shown on this map. (If you have difficulties with reading the small letters, I can tell you that the legend for the German area is the lowest one in the legend box.)
In Danish:
In German:
Nodule growth is extremely slow – on the order of a centimeter over several million years. Several processes are involved in the formation of nodules, including the precipitation of metals from seawater (hydrogenous), the remobilization of manganese in the water column (diagenetic), the derivation of metals from hot springs associated with volcanic activity (hydrothermal), the decomposition of basaltic debris by seawater (halmyrolitic) and the precipitation of metal hydroxides through the activity of microorganisms (biogenic). Several of these processes may operate concurrently or they may follow one another during the formation of a nodule.Since the 1960's manganese nodules have been recognized as a potential ore source. Germany seems finally willing to do something serious about it.
Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) in Hannover, Germany, has from the International Seabed Authority received an exploration licence for 15 years in 75.000 km2 sea-bed of the Pacific Ocean between Mexico and Hawaii - in the Pacific Nodule Belt between the Clarion and Clipperton fracture zones.
German geologists recently carried out an extended research project in the Pacific. They wanted to find out how many manganese nodules there are, and where they are scattered. 24 million tons of precious metals are believed to be lying under the world’s oceans. The German geologists are trying to learn whether the nodules could be recovered from the seabed without damaging the environment, and which technology would be best suited to do that.
The Pacific nodules contain on average 15-30% manganese, 7-15% iron, 1,2% nickel, 1% copper and 0,3% cobalt. They can have a diameter of up to 50 cm and are mainly found at a depth of 4-5 km. Together they may contain thousands of billions of tons manganese.
The area between the Clarion and Clipperton fracture zones and the areas belonging to different contractors are shown on this map. (If you have difficulties with reading the small letters, I can tell you that the legend for the German area is the lowest one in the legend box.)
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http://www.deutsche-welle.de/dw/article/0,,4408892,00.html
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http://www.cartage.org.lb/en/themes/sciences/Earthscience/Oceanography/OceanSediments/Manganesenodules/Manganesenodules.htm
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http://www.springerlink.com/content/44p012947k652226/
In Danish:
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http://ing.dk/artikel/101514-tyskland-vil-hente-metal-i-dybhavet?utm_medium=rss&utm_campaign=nyheder
In German:
WIDGETIZE