Desarrollo de la Antártica

EL DESARROLI.O DE I.A ANTÁRTICA 9, geological and geophysical evidence has suggested that 30 0 W ......... lOO ,E, 10° ,E ,-..; 30° E 300 E ......... 8oo E and 110° E ......... 170° E of the Antaretic continent coasts were connected to the eastern coast of South Africa, Madagascar, the eastern coast of India and I:he southern coast of Australia respeetively in Gondwana Land formatÍon. The mineral deposits in Africa, Madagascar, India and Australia have . been reasonably well iknown and a number of them are being ex– ploited. Tille mineral deposits in these continents are ferrous metaIs (magnetite and other iron ores), base metals (Cu, Pb, Zn, Mo, etc.) , precious metals and stones (pt, IAu, Ag, Diamond, etc.) and other metals (U, \V, Ti, Cr, Ni, Be, ete.). Beeause of the continuÍty of geological formations throughout Antarctica, Australia, India, Ma– dagascar and Afriea in ~he old Gondwana Land, the probability of the presenee of eaeh ore deposit Ín Antarctica ean be evaluated by interpolations and extrapolations of the known data of number of the deposit in !'he other eontinents on the basis of the continuity (Jf geoIogical formation. The following tabIe (Taible 11) is a result thus estimated for {he probable number of deposits of four different groups of metallie ores in the Antarctic Shield (Wrig1ht and Wimams, 1974) . TABI.E 11 NUMBER OF ORE DEPOSITS IN AUSTRALIAN, INDIAN, MADAGASCAR AND AFRICAN SHIELDS AND THE EXPECTED NUMBER OF DEPOSITS IN ANTARCTIC SHIELD Depasit Shíelds Expected far Antarctic Australia India Madagascar Africa Total Shield Ferrous metals 9 57 15 76 157 138.4 Base metals 17 5 6 49 77 68.9 Precious metals 9 5 13 48 75 66.1 Other.s 5 28 10 40 83 73.2 (after 'Vright and Williams, 1974) The expected number of ore deposits Ín the Antarctic Shield is e~· timated simpIy by the ratio of Antaretic Shield area to uhe total area of the other four shields. Hbwever, the major parts oí il\ntarctic shield is covered by the ice sheet, the total exposed rock areas being only 0.21 % of the whole shield area. If we are concerned only with the exposed area for estimating the probahility to find mineral deposits, the probable number of deposits must be much redueed as shown 122