We have demonstrated that Heliometric data can be efficiently used in mineral resources exploration
MINERAL EXPLORATION
Helium gas is an inert, extremely mobile light gas, which serves as an indicator of zones of increased permeability of the section, zones of active tectonic disturbances.
A huge number of deposits of solid minerals, both ore and non-metallic, are associated with fault zones, weakened cover zones, along which the melt was intruded and in which, at present, mineral deposits are spatially located.
The relationship of elevated helium concentrations in groundwater over various deposits of solid minerals associated with deep fault zones was revealed back in the 70s of the last century by soviet researchers - I.N. Yanitsky, A.N. Eremeev, L.N. Ovchinnikov ,
A.I., Fridman and others.
At the same time, the nature of the concealment of the deposit (not coming to the surface, covered by a cover of neoformations) does not play a role - because faults that retain at least a slight tectonic activity cut through the entire section and will be expressed in the surface field of helium.
Thus, it is obvious that helium surveying is a useful indirect method for predicting solid mineral deposits, which performs the function of mapping modern active zones of increased permeability - potential reservoirs of mineral matter.
Kimberlite and Сarbonatite
The morphology (tubularity, zoning) of carbonatite and kimberlite bodies is similar, the general principles of their formation are also similar, and indicates the commonality of fault tectonics inside and on the periphery of the bodies. That is, both carbonatite and kimberlite bodies, characterized by fault tectonics, will be reflected in the surface helium field in the form of positive anomalies, ring structures, etc.
Helium has been successfully used in mapping kimberlite pipes in Yakutia, overlain by a thick layer of traps (several hundred meters), Yu.R. Yurkevich, 1980-81.
Gold deposits (Hydrothermal type)
Gold and hydrotherms
Most of the world's gold deposits were formed as a result of hydrothermal processes, that is, as a result of the deposition of gold and its accompanying minerals from hot aqueous solutions (hydrotherms). The main companions of native gold in these deposits are quartz and sulfur compounds of heavy metals (iron, lead, zinc and copper sulfides).
Hydrotherms and permeability
The formation of ancient, as well as modern hydrothermal systems, namely, their geometry, is closely related to zones of increased permeability of the earth's crust, zones of active faults, etc.
A hydrothermal ore deposit is fossil evidence of a hydrothermal-rock interaction. For its formation, hydrotherms must filter through the rock, that is, there must be channels, paths along which the fluid moves. If the rock is impermeable, then only a small amount of fluid will be able to pass through and there will be little heat transfer.
Thus, knowledge of the geometry of permeability zones can be used to predict the localization of ore formation sites.
Permeability and helium
As is known and repeatedly proven, helium gas is an indicator of zones of increased permeability of the section and, in surface conditions, forms anomalies above the zones of tectonic disturbances - active faults. This property of helium is successfully used by us in many areas of geology - in structural, engineering, and petroleum geology.
Obviously, the localization of zones of increased permeability is also important and useful for ore exploration geology - as a tool for localization of probable zones of hydrothermal mineralization, receptacles of various ores.
Many noted cases of anomalous helium content over known endogenous mineralizations observed in various parts of the world (see Fig. A.N. Eremeev et al., 1972), of course, cannot be a mere coincidence, but indicate the presence of single permeable feed channels, along which solutions moved in the past, ore matter was deposited, and at present, they remained permeable to helium.
Helium survey in the search for hydrothermal gold deposits
From the foregoing, it is clear that land-based helium survey has prospects for use in the search for certain types of gold deposits, namely the hydrothermal type associated with faults and permeable zones.
The results of the helium survey must be combined with all available geological and geophysical data on the site for a competent sorting of anomalies.