Petromagnetic heterogeneities of stress: applied corollary of Villari effect

Abstract

Practice of geologic-geophysical works in the territory of the Yakut kimberlite province showed that search of radical diamond fields in the zones of epigenesis surrounding them interferes with difficulties of obtaining proofs of the reasons of change of the containing breeds of a carbonaceous socle, which are defined by a variety of manifestation of physical and chemical processes. It generates ambiguity of interpretation of geologic-geophysical materials and, as a result, leads to omission of promising sites with kimberlite bodies, or authentication of obviously unpromising territories by expensive drilling. Thus, in order to purposefully conduct searches for kimberlites, it is necessary to know characteristics of chemical, physical, etc. effects genetically related to structures of diatreme association. Becoming of kimberlites has, mainly, the dynamic effect on the surrounding geological formations. As a result of the Villary effect (the change in the magnetic properties of the body during its deformation), in the sedimentary rocks of the zone of dynamic influence of the kimberlite body, petromagnetic heterogeneities of stress are formed that differ from the sterile rocks of the carbonaceous socle by specific values of parameters of anisotropy of magnetic susceptibility (AMS). This effect is advisable to use as a petrophysical search criterion of presence of promising areas of kimberlite bodies. Earlier, such changes of the AMS parameters because of pressure, for the purpose of solving applied geologic-geophysical problems, were not carried out and were performed by the authors for the first time.