Types of Dispersion
There two different types of dispersion:
Primary dispersion: united to phenomena of formation or arrival of minerals, like for example, hydrothermal alteration or magmatic differentiation. The study of these “primary abnormalities” is done through the recognising of the deposit by means of a rock sample. Through the choice of “indicating” elements between the main constituents the rock covering and the metallic mineralization elements, it is possible to outline the “halos” and determine the gradients and the polarity in the nearby areas of the deposit.
Secondary dispersion: is united to the phenomenon of superficial and geomorphologic alteration. In this case the dispersion by the movement of clastic fragments occurs mainly on the surface where the erosion is able to act. The main force that is responsible of the mechanic dispersion is gravity. It is important to know that the movements of fragments and rock occur in the softest inclinations known as creeping. In template and humid weather the movement is made easier by the lubricating effect of humidity. If movement increases, a flow of mixed material with water can start up and can move in a catastrophic way. In this case geochemical abnormalities from the ground can be moved along or covered. These dispersions, which are sometimes mechanical, or sometimes chemical, starting from the mineralized area, destabilizes oxidation, causing “halos” and “secondary effluvium” that cover most of the surface of that produced by the intersection with the surface of the hidden mineral concentration by different re-coverings. in all the cases of geochemical prospection, whether it is strategic or tactic, it is these secondary halos that needs to be highlighted on through the chemical analysis of the floor samples, of sediments of water courses, as well as somewhat disaggregated rocks. It is necessary to consider that the elements associated to a deposit can have totally different mobility and can give origin to abnormalities that cannot be overcome. For example, Pb and Zn are often times associated in the deposits and in the superficial alteration conditions zinc is a lot more easily lixiviated than lead and can be transported to great distances as far as Pb that in change produces abnormities directly over the mineralization.