457 



Underwater photographs of blankets of manganese nodules have 

 been studied, and concentrations in pounds per square foot have been 

 computed, mainly for the Pacific Ocean. An American expert has 

 estimated that the Pacific Ocean may contain more than 1,600 billion 

 tons of manganese nodules which are being formed at the rate of 

 about 10 million tons per year. Russian specialists, on the other hand, 

 estimate a total Pacific Ocean surficial tonnage at about one-twentieth 

 of this.-"' 



RED SEA GEOTHERMAL DEPOSITS 



Perhaps one of the most significant of recent oceanographic dis- 

 coveries is that of the bizarre pools of hot brine on the floor of the Red 

 Sea. Unusually saline water in the Red Sea has been known since the 

 Russian expedition of the Vitiaz in the 1880's. In the mid 1960s, how- 

 ever, more startling data were obtained by the British RRS Discovery, 

 followed by the U.S. (Woods Hole) vessel Atlantis II, and several 

 others. The Discovery sampled water with a temperature of 111 degrees 

 Fahrenheit and a salinity of 256 parts per 1,000. 26 Atlantis II measured 

 a brine temperature of 133 degrees F. and obtained bottom sediment 

 samples having a temperature of 144 degrees F. and containing a mix- 

 ture of metal compounds, principally oxides and sulfides of iron, man- 

 ganese, zinc, and copper. 



Geothermal heat from the molten interior of the Earth is trans- 

 mitted to the Red Sea water through the fissures along the rift of the 

 Red Sea floor. The heated waters dissolve salts from sedimentary rock 

 formations and leach heavy metals out of crustal volcanic rocks, creat- 

 ing metal-saturated brine. As this metalliferous brine cools it releases 

 the sulfides of lead and zinc, and the carbonates of iron contained in the 

 water. 



This has been the theory generally accepted by oceanographers. 

 The Russian scientist D. D. Kvasov, of the Leningrad Academy of 

 Science, has proposed another theory suggesting that the brine pools 

 may be ancient, lakes. 27 Whatever the explanation, the total brine- 

 free sediments at one location only, the Atlantis II Deep, is estimated 

 to be over 50 million tons. It contains appreciable amounts of zinc, 

 copper, lead, silver, and gold which, at current smelter prices, would 

 be worth about $2.5 billion. 28 



The significance of the Red Sea discoveries lies in the inter- 

 related factors of scientific knowledge, exploitation, and legal control. 

 Scientific knowledge will lead to discoveries of similar deposits in 

 submarine environments having analogous geological character- 

 istics. This development, in turn, will have its special economic con- 

 notations and present, ultimately, the legal and international prob- 

 lems of exploiting these resources. 



25 Mero, op. cit., page 174, estimated the total Pacific Ocean nodules to be 1,656 billion 

 metric tons. N. Zenkeviteh and N.S. Skornyakova, In Natura (3, 1961), pages 47-50, 

 obtained an estimate of 90 billion metric tons. 



16 Average ocean salinity is 35 o/oo, which means 35 grams of solid material contained 

 in 1,000 grams (1 kilogram) of sea water. Normal Red Sea salinity is 40 o/oo. 



21 D. I). Kvasov. "Limnological hypothesis of the origin of hot brines in the Red Sea." 

 Nature (Vol. 221. March 1, 1969), pages 850-851. 



28 J. L. Bischoff and F. T. Manheim, "Economic potential of the Red Sea heavy metal 

 deposits." In E. T. Degens and D. A. Ross, eds. "Hot Brines and Recent Heavy Metal 

 Deposits in the Red Sea, A Geochemical and Geophysical Account." (New York, Springer- 

 Verlag, 1969), page 535. 



