Anomaly hydromorphic

Selective leach techniques have become popular in mineral exploration for the treatment of geochemical soil samples. Their popularity stems from the fact that they are considered to extract selectively a particular hydromorphically-transported component of metals in the sample and, as such, show better anomaly-to-background contrasts than do conventional strong acid digestions which dissolve most of the chemical matrix of the soil. 

The rationale for using Hg as a pathfinder element in mineral exploration is attractive. Because of its volatility, Hg is presumed to form broader halos in the hypogene environment than most elements. It is envisaged that both vapour-phase and solution transport are responsible for a wide dispersion of the element. In the secondary environment it is well known that Hg exerts a measurable vapour pressure at ambient temperatures and possesses redox properties that allow the metal to exist in the elemental state under a range of natural conditions. Therefore it has been claimed that, as a host sulphide-body weathers, it can be expected that Hg will be converted partly to the vapour state, thereby overcoming the constraint of hydromorphic or solution dispersion that applies to other target and indicator elements. Vapour-phase dispersion through permeable rock or cover would allow Hg to be detected in soil or soil gas, and perhaps as an atmospheric anomaly. 

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