Feedback Concept in the Ore-forming Systems

Feedback, one of the most fundamental processes existing in nature, is present in almost all dynamic systems. Feedback concepts have been utilized almost exclusively by engineers. Nevertheless, this theory is applicable to formulating and solving problems in geology, particularly in the ore-forming systems. Feedback is distinctly operative in the generation of two groups of mineral deposits: (i) Mineral deposits showing rhythmic structures/textures, such as layered chromite deposits, re-opened veins with banded structure/texture, Mississippi Valley-type deposits with alternate bands/crusts of barite and galena, proximal volcanogenic massive sulfide deposits with mineralized layers of breccia clasts, and banded iron formations with alternate silica and magnetite and/or hematite bands, and (ii) mineral deposits lacking visible rhythmic structures/textures, but showing evidence of rhythmic process(es), such as in porphyry base metal deposits. There is an alternation of positive and negative feedback mechanisms in the ore-forming systems discussed here, which implies the involvement of feedback loops of negative sign.