Minerals Report - International Seabed Authority
Minerals Report - International Seabed Authority Minerals Report - International Seabed Authority
metre or metres of these black smokers, the temperature is again very close to the ambient temperature. Temperature measurements showed that the heat output here was about the same heat output from one of a complex of black smokers. These are therefore also geothermal resources in addition to mineral resources, Professor Rona pointed out. Hot springs have been found along the axis of the East Pacific rise where the hot material is welling up at a relatively fast spreading rate. Professor Rona stated that the East Pacific rise is part of the Pacific Ocean basin that is referred to as the "Ring of Fire" because it is the most volcanically active region of the earth. He informed participants that it was initially thought that hot springs would only occur in the Pacific because of the high levels of volcanic activity as compared with other parts of the world oceans where there is less volcanic activity such as the Atlantic and the Indian Oceans. Professor recalled an expedition that he led to the submerged volcanic mountain range between North America and North West Africa in search of hot springs, based on clues derived from activity in the submerged volcanic range near the island of Iceland. The expedition confirmed the presence of hot springs in the Atlantic, and gave birth to the term “Geyser” or a hot spring in which water intermittently boils, sending a tall column of water into the air, based on the clues for these springs in the Atlantic that were obtained from Geysir, in Iceland. At the base of the toppled chimneys, a study of the material in the oxidation ring of this rubble was made. It was found that most of the material is sulphide minerals that have been oxidized, but an extremely tiny bright spot, no more than a pin head, was also discovered. That bright spot was a grain of pure gold, and indeed the first grain of pure gold that was found at one of these deposits in the deep ocean basin. The significance of this finding was that prior to this discovery though gold was known to be associated with massive sulphides, it was thought to be concentrated after the deposits were uplifted onto land by water processes. This discovery showed for the first time that gold was concentrated in these deposits on the deep sea floor. Professor Rona stated that divergent plate boundaries with the potential for the occurrence of massive sulphides deposits lie primarily in the international seabed area with exceptions mostly in the volcanic island chains INTERNATIONAL SEABED AUTHORITY 20
of the western Pacific. The volcanic island chains form at convergent plate boundaries where the lithosphere bends down and descends into the Earth's interior where it is destroyed to counterbalance the creation of lithosphere at divergent plate boundaries. The components of seafloor hydrothermal systems consisting of hot rocks at depth beneath the seafloor as a heat source, seawater as the circulating fluid, and permeable pathways through volcanic rocks that contain metals are present at discrete sites on two sides of these volcanic island chains. The settings favourable for the formation of massive sulphide deposits and associated manganese deposits on the two sides of the volcanic island chains are the calderas (collapsed centres) of seafloor volcanoes and seafloor spreading centres in the back arc basins. These seafloor-spreading centres are similar to, but generally smaller scale than, the submerged volcanic mountain range at divergent plate boundaries. Examples of these settings at the front and back sides of volcanic island chains are, the Sunrise deposit in the calderas of an active seafloor volcano in the fore-arc side of the Isu-Ogasawara Arc south of Japan and the PACMANUS hydrothermal field in the Manus back-arc basin on the north side of Papua New Guinea, respectively. A characteristic of these mineralised seafloor sites in the western Pacific is that they lie not only within the 200 nautical mile zone of adjacent coastal states but, in certain cases, lie in overlapping 200 nautical mile zones. Professor Rona pointed out that there was also another type of hydrothermal deposit in the deep ocean which is less known. These deposits are found where lower temperature solutions discharge within kilometres of higher temperature fields. These lower temperature solutions deposit a very pure manganese deposit i.e., a manganese crust. The deposits contain over fifty percent manganese. Going from the deep ocean basins to the types of deposits that have a double source, that is the continents on the one hand and the deep ocean basin on the other hand, Professor Rona explained that before plate tectonics all the manganese in marine mineral deposits was thought to be supplied by manganese dissolved from continental rocks and carried into the ocean by rivers. While this may have been provided an adequate explanation for the composition of polymetallic nodules, the hot springs are a second source of the metals in polymetallic nodules. It has been found that the composition of INTERNATIONAL SEABED AUTHORITY 21
- Page 2 and 3: Workshop on Minerals Other than Pol
- Page 4 and 5: Published in Jamaica 2004 by the In
- Page 6 and 7: Chapter 6* Impact of the Developmen
- Page 8 and 9: PART 4 REGULATORY AND PROMOTIONAL F
- Page 10 and 11: The Authority designates one of two
- Page 12 and 13: deposits and gas hydrates of the co
- Page 14 and 15: Prof. Chris German, Challenger Divi
- Page 16 and 17: Mr. Sven Petersen, Research Associa
- Page 18 and 19: SECRETARIAT Ambassador Satya N. Nan
- Page 20 and 21: is to submit “an application that
- Page 22 and 23: that was established to help protec
- Page 24 and 25: on the continental margin. He state
- Page 26 and 27: with the German firm Preussag. As p
- Page 30 and 31: nodules in terms of these metals -
- Page 32 and 33: Professor Herzig stressed however t
- Page 34 and 35: While noting that the continuity of
- Page 36 and 37: asal diameter at 1,600 m water dept
- Page 38 and 39: discovery of the new hydrothermal s
- Page 40 and 41: esearch cruises dedicated to ferrom
- Page 42 and 43: global mid-ocean ridge system. He p
- Page 44 and 45: athymetric map of the seafloor. A s
- Page 46 and 47: were encouraging. In the course of
- Page 48 and 49: that this matter was sensitive, he
- Page 50 and 51: complete a preliminary evaluation o
- Page 52 and 53: metals - nickel, cobalt, manganese,
- Page 54 and 55: 12. Issues to be taken into account
- Page 56 and 57: entities. Many of them included min
- Page 58 and 59: In this regard, the Secretary-Gener
- Page 60 and 61: According to Dr. Vysotsky, as estim
- Page 62 and 63: With regard to current knowledge ab
- Page 64 and 65: Dr. Corbett gave a brief account of
- Page 66 and 67: River resulting in the introduction
- Page 68 and 69: Ms. Zaamwani pointed out that as th
- Page 70 and 71: geochemical and geotechnical survey
- Page 72 and 73: of its continental shelf through bi
- Page 74 and 75: also stated, is similar to that of
- Page 76 and 77: Chapter 7 Technical requirements fo
metre or metres of these black smokers, the temperature is again very close to<br />
the ambient temperature. Temperature measurements showed that the heat<br />
output here was about the same heat output from one of a complex of black<br />
smokers. These are therefore also geothermal resources in addition to mineral<br />
resources, Professor Rona pointed out.<br />
Hot springs have been found along the axis of the East Pacific rise<br />
where the hot material is welling up at a relatively fast spreading rate.<br />
Professor Rona stated that the East Pacific rise is part of the Pacific Ocean<br />
basin that is referred to as the "Ring of Fire" because it is the most volcanically<br />
active region of the earth. He informed participants that it was initially<br />
thought that hot springs would only occur in the Pacific because of the high<br />
levels of volcanic activity as compared with other parts of the world oceans<br />
where there is less volcanic activity such as the Atlantic and the Indian<br />
Oceans. Professor recalled an expedition that he led to the submerged<br />
volcanic mountain range between North America and North West Africa in<br />
search of hot springs, based on clues derived from activity in the submerged<br />
volcanic range near the island of Iceland. The expedition confirmed the<br />
presence of hot springs in the Atlantic, and gave birth to the term “Geyser” or<br />
a hot spring in which water intermittently boils, sending a tall column of<br />
water into the air, based on the clues for these springs in the Atlantic that<br />
were obtained from Geysir, in Iceland.<br />
At the base of the toppled chimneys, a study of the material in the<br />
oxidation ring of this rubble was made. It was found that most of the material<br />
is sulphide minerals that have been oxidized, but an extremely tiny bright<br />
spot, no more than a pin head, was also discovered. That bright spot was a<br />
grain of pure gold, and indeed the first grain of pure gold that was found at<br />
one of these deposits in the deep ocean basin. The significance of this finding<br />
was that prior to this discovery though gold was known to be associated with<br />
massive sulphides, it was thought to be concentrated after the deposits were<br />
uplifted onto land by water processes. This discovery showed for the first<br />
time that gold was concentrated in these deposits on the deep sea floor.<br />
Professor Rona stated that divergent plate boundaries with the<br />
potential for the occurrence of massive sulphides deposits lie primarily in the<br />
international seabed area with exceptions mostly in the volcanic island chains<br />
INTERNATIONAL SEABED AUTHORITY 20
Change language