65
Chapter 4
Characteristics and Formation Process
Yves Fouquet
Y. Fouquet ()
Centre Bretagne, Géosciences marines,
Ifremer, BP 70, 29280 Plouzané, France
e-mail: Yves.Fouquet@ifremer.fr
Introduction
Scientific exploration carried out over the past 30 years has identified several geological and geochemical processes leading to the concentration of metals in the
deep sea. These discoveries open up new prospects for the exploration and identification of ocean mineral resources. Furthermore, the mineral deposits discovered
(hydrothermal sulphides, nodules and manganese crusts) are related to specifically
submarine processes which have no land-based equivalent on the continental crust.
According to the context and type of substrate involved, hydrothermal mineral deposits can contain high concentrations of copper, zinc, gold, silver, cobalt, lead and
barium, but also rarer elements such as cadmium, antimony, cobalt, germanium,
indium, selenium and mercury.
Due to the salinity of seawater and the increase in boiling point with depth, the
deepest fluids have a greater capacity to transport metals. Manganese oxide nodules
and crusts are of interest for their nickel, copper and cobalt concentrations, but they
can also be rich in platinum, titanium, rare earths (in particular cerium), zirconium,
molybdenum, vanadium, tellurium, thallium and phosphorus. All these mineral deposits are found directly on the ocean floor. When exploited, this should reduce
environmental impact. Furthermore, unlike land-based mining facilities, specific
facilities on board a vessel can be easily relocated. Thus, small deposits very rich in
metals, which would never be exploited on land, could be of economic value.
Following a brief reminder of the mineral deposits exploited on the continental
shelf, deep-sea mineral deposits will be studied, by presenting the main characteristics of their geological environment, their composition and the geochemical
processes which lead to metal transport and concentration.
Y. Fouquet, D. Lacroix (eds.), Deep Marine Mineral Resources,
DOI 10.1007/978-94-017-8563-1_4, © Éditions Quæ 2014
Chapter 4
Characteristics and Formation Process
Yves Fouquet
Y. Fouquet ()
Centre Bretagne, Géosciences marines,
Ifremer, BP 70, 29280 Plouzané, France
e-mail: Yves.Fouquet@ifremer.fr
Introduction
Scientific exploration carried out over the past 30 years has identified several geological and geochemical processes leading to the concentration of metals in the
deep sea. These discoveries open up new prospects for the exploration and identification of ocean mineral resources. Furthermore, the mineral deposits discovered
(hydrothermal sulphides, nodules and manganese crusts) are related to specifically
submarine processes which have no land-based equivalent on the continental crust.
According to the context and type of substrate involved, hydrothermal mineral deposits can contain high concentrations of copper, zinc, gold, silver, cobalt, lead and
barium, but also rarer elements such as cadmium, antimony, cobalt, germanium,
indium, selenium and mercury.
Due to the salinity of seawater and the increase in boiling point with depth, the
deepest fluids have a greater capacity to transport metals. Manganese oxide nodules
and crusts are of interest for their nickel, copper and cobalt concentrations, but they
can also be rich in platinum, titanium, rare earths (in particular cerium), zirconium,
molybdenum, vanadium, tellurium, thallium and phosphorus. All these mineral deposits are found directly on the ocean floor. When exploited, this should reduce
environmental impact. Furthermore, unlike land-based mining facilities, specific
facilities on board a vessel can be easily relocated. Thus, small deposits very rich in
metals, which would never be exploited on land, could be of economic value.
Following a brief reminder of the mineral deposits exploited on the continental
shelf, deep-sea mineral deposits will be studied, by presenting the main characteristics of their geological environment, their composition and the geochemical
processes which lead to metal transport and concentration.
Y. Fouquet, D. Lacroix (eds.), Deep Marine Mineral Resources,
DOI 10.1007/978-94-017-8563-1_4, © Éditions Quæ 2014