Conductivity anomalies in the zones of anartozit and alkaline magmatism on the Ukrainian shield

: pp. 109 - 111
Received: August 01, 2013
Subbotin Institute of Geophysics of National Academy of Sciences of Ukraine
Subbotin Institute of geophysics of National Academy of Sciences of Ukraine

Ingul megablock and Ingul-Kryvoy-Rog suture zone at the depth range of 20 to 30 km, ρ is up to 100 Ohm∙m), Eastern-Preazovian anomaly (related to Gruzko-Elachinsk and south part of Kalmiuss fault zones at the depth of up to 10 – 50 km, ρ < 100  Ohm∙m), and Korosten, Korsun-Novomirgorod and Eastern-Preasovian massifs of anorthosite and alkaline rocks. Within the boundaries of Ukrainian shield Kherson-Smolensk trans-regional tectonic seam coincides with the western branch of the Kirovograd anomaly, while trans-regional tectonic Donetsk-Bryansk seam is intersected by two different electric conductivity anomalies, Preazovian anomaly and Donbass anomaly. Anorthosite massif are related to "transformation" zones of discharge of deep fluid and of generation of melts at the depth ranging from about 200 km (kimberlites and ultrabasic) to about 20 km (granites). The fault zones were formed in the Proterozoic period between 2.0 to 1.6 billion years ago. However, the resumption of tectonic activity is observed in the course of Phanerozoic period and to the present. At the present stage geoelectric methods reveal emergence of anomalous (by properties) zones on the crust-mantle boundary and in the crust itself. Originality. For the first time deep faults are examined in details as zones of increased permeability in which (through the lithosphere) discharge of mantle fluids takes place. The relationship between the conductivity anomalies, with parts of Korostensky, Korsun-Novomirgorod and East Priazovsky massif of anorthosite and alkaline rocks. It is assumed that the formation of these massifs is associated with the transform fault zones: the regional Proterozoic-Kherson-Smolensk, at the present stage manifested in Zvenigorod-Annovskoy and Kirovograd; Gruzsko-Elanchikskoy; Zvizdal-Zaleskaya. It is suggested that the formation of these massifs is related to transformation fracture zones; to proterozoic regional Kherson-Smolensk zone that at the present stage manifest itself in Zvenyhorodka-Annovskoy and Kirovograd-Ingul megablocks, to Gruzsko-Elanchikskoy Pryazovian megablock, to Zvizdal-Zaleski Volyn megablock of Ukrainian shield. There was examined a relationship between electrical conductivity anomalies and parts of Korosten, Korsun-Novomirgorod and Eastern-Preazovian massifs of anorthosite and alkaline rocks. Practical significance. The results of this research will allow us to determine nature of the anomalies of electric conductivity and to clarify the fundamental questions of the genesis of mineralization in the upper mantle and the crust of the Ukrainian shield.

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