Reconstruction physicochemical conditions frasnian-famennian carbonate deposits on electron paramagnetic resonance data

Abstract

© SGEM2018. The paramagnetic properties of core samples from the section of the reference well were performed on 62 samples (1478,1M – 1455,3м interval) Zadon’s horizon Famennian period by electron paramagnetic resonance (EPR) for mineral associations of the of the Upper Devonian deposits of the Volga-Ural region of the Republic of Tatarstan. Thus, a complex of geochemical EPR parameters of rocks (Mn2+, Fe3+ in limestones, anionic complexes SO3, SO2, PO2, alfa = 15 * I (Mg)/I (Ca) ions Mn positions Mg/Ca in dolomite, C600), and logging for the work on the refinement of rhythms, stratigraphic cycles of Frasnian-Famenian carbonate deposits.. The main feature of the structure of the Zadon’s horizon is that, in addition to dolomites, dolomites calcareous and calcareous, dolomite and dolomite limestones are involved in the formation of carbonate rocks. Separate interlayers contain only limestones. The phosphate component is contained only in the dolomites, which are confined to the packs containing anhydrite, and is of the same nature as in the Liven’s and Evlan’s horizons: the interval 1472.9 m-1470.4 m. This cycle indicates that the initial stage of the transgressive cycle was unstable and stabilized, starting at 1460.1 m. It is shown that the formation of reservoir properties of rocks in the section under study is due to both superposed tectonic factors and primary sedimentation characteristics of rocks. The regressive cycle is distinguished by the fact that in the Frasnian stage upwards in the section the carbonates are enriched in manganese as the basin is shoaling (the regularity of Ronov AB). The boundaries of the rhythms are marked by samples in which the ion concentrations of the PO2-, SO3- anhydrite radicals are increased, as well as low values of the parameter alfa and the content of Mn2+ ions.