solution métallifère

CONT: Les gîtes [...] se trouvent là où des fractures, failles ou autres ouvertures ont créé des conditions favorables au dépôt de minéraux et où des solutions ou vapeurs métallifères ont pu exercer leur action. Certains gîtes semblent avoir comblé une fente ou autre espace libre, d'autres semblent avoir exercé une pression pour écarter les parois d'une fissure.

CONT: Less obvious, but supported by increasing evidence, is the significant part played by living organisms, especially bacteria and algae, on the precipitation of metals from solutions. The process may take place from surface solutions at atmospheric temperature and pressure or from hot solutions of igneous origin. Bacterial precipitation may occur on the bottom of lakes or inland seas, for example the currently active precipitation of metals on the floor of parts of the Red Sea. The close association of life with metalliferous solutions on the floors of oceans was spectacularly shown in an illustrated article in the National Geographic Magazine (Vol. 156, No. 5) of November 1979.
CONT: ... metal-bearing solutions seep through permeable sedimentary rocks relatively close to surface and precipitate the metallic minerals in pore-spaces or fractures or by replacement of non-metallic minerals. This process seems to have been responsible for lead-zinc deposits of the Mississippi Valley type.
CONT: Circulating meteoric waters may include metallic solutions, which are deposited in fissures as veins or in caverns as large ore masses. Replacement deposits occur when dissolved limestone is replaced with metallic minerals, as in the lead and zinc deposits of Missouri and Wisconsin.