KECENT PROGRESSES ON THE STUDIES AND SEARCHES FOR SUPERLARGE MINERAL DEPOSITS
Tu Guangzhi(Institute OF Geochemistry,Academia Sinica,Guiyang,550002)
Some recent progresses pertaining to the studies of superlarge mineral depositsare reviewed.The definition,classification,typical examples,tpyes of mineralization andglobal background of superlarge deposits are discussed. There are disputes on the definition of superlarge deposits and similar terms(worldclass,giant,etc.).The term“superlarge”should have priority over other similar terms,since it was first adopted at an international symposium of IUGG(1987).Based onChina,s reality,it is proposed by the All China Ore Reserve Committee(1987)that thelower limit of the ore(or metal, mineral)reserve of a superlarge deposit should be 5 timesthat of a large-sized deposit. Three groups of superlarge deposits can be recognized.Thefirst group includes those with followers of large-,medium-to small-sized deposits of thesame kind. The second group of superlarge deposits has hardly any followers while thethird group comprises superlarge deposits with transitional characters. It should be point-ed out that for many nonferrous metals there are several types of mineralization with in-dustrial significance,but superlarge deposits are generally confined to one or two types ofmineralization. This is an important empirical rule in searching for superlarge deposits.Examples are cited to show the importance of global background studies for superlarge de-posits.