Some philosophical premises for the formation and occurrence of large metal accumulations in the crust
published: Jan 1, 1989
ArtNo. ESP136000302002, Price: 19.00 €
Ore deposits in the broadest context are the result of favourable coincidence of economic, technological and geologic conditions. Although at present the bulk of metals is recovered from "classical" deposits that also represent significant and accurately outlined, local sites of anomalous geochemical accumulation and concentration, there are exceptions (e.g. the world ocean as an "orebody" of Mg recovered from seawater) and more are to appear in the future. In the present paper, only the "classical" metallic deposits of anomalous magnitude (giant and supergiant in the sense of Laznicka, 1983) are considered. Most of the existing attempts to explain (and in the future predict) the large metal accumulations suffer from excessive (sometimes quasireligious) determinism. Typically, the problem is approached by assembling a hierarchy of the strongest presently popular geological agents, structures and processes (such as Benioff zones, rifts, lineaments, anomalous mantle spots) as a first step, followed by attempts to tie to some of their effects the giant metal deposits usually as a poorly discriminated global set, or as a collection of best-fitting examples. Because numerical data are rarely used and there are no limiting constraints on distances, timing, "weight" of influence, etc. between the deposits and the supposed governing agents, a "fit" can almost always be demonstrated.