Time factor in ore genesis (Evolution and distribution patterns of mineral deposits)
Rundqvist, D. V.
published: Jan 1, 1984
ArtNo. ESP136000203001, Price: 19.00 €
Mineral deposits of the same type, developing in similar geological settings but at various "absolute" times (in geological history) or at "relative" times (during tectono-magmatic or tectonosedimentary cycles) time, show different extent of mineralization. Deposits of a particular metal or a particular kind of raw material exhibit their own distribution maxima in geological history, due to a combination of factors of both endogenous and exogenous evolution. Two series of successive occurrence of accumulation maxima of multitype ores are outlined below: A major series defining the main evolutionary path (from Cr, Ti, Fe to Sb, Hg) and a complementary one (from REE, rare metals, Sn, W to sulfides of Pb, Zn, Sb, Hg), the latter being characteristic of crustal blocks under destructive conditions. As evidenced by metallogenic data available for the USSR, the accumulation maxima of ores of a particular composition in different time-spans are represented by different genetic and formational types. Further analysis of the evolution of mineral units, i.e. minerals, rocks, ores and formations, requires the preparation of a scale of periodicity in addition to an adopted geochronological scale. Such a scale, based predominantly on distribution patterns of mafic, ultramafic, alkaline and granitoid rocks, is presented for discussion here.