Underground temperature background of Saksagan iron-ore region in Kryvyi Rih basin

Abstract

The data from thoroughly selected 46 deep exploration boreholes drilled along the Saksagan iron-ore stripe located in the Kryvbas and a transverse section of the stripe, which included results of studies conducted in the Kryvyi Rih super-deep borehole SD8, have served as the data bank for analyzing and calculating the temperature background parameters. The methodical procedures for ordinary measurements averaging, determining and generalizing temperature values and other thermal background parameters were given. The distribution of temperature along the strike of the Saksagan ironore stripe from the south-west to the north-east within the depth range from 0 m to 2000 m was shown. The whole territory of the Saksagan iron-ore stripe from the Rodina Mine in the south was divided into 7 sites, approximately equal in area, each of sites contained at least 4 boreholes. The area-averaged and the depth-averaged data were calculated for each of the sites. The averaging depth range was 500 m. The pattern of the anomalous isotherms has shown the anomalous field to be very diverse, and can be defined as the alternation of negative and positive thermal fields, complicated by local anomalies in the northern direction. The characteristic of the geothermal gradient after the averaged data of 46 deep boreholes drilled along Saksagan iron-ore stripe was given. The given data allow us to state about high variations of GTG values. The obtained results will be greatly appreciated in interpreting the features of the overall structure of the Kryvbas, especially its western side and the central part tectonics, by hydrogeological and mining services in view of further deepening of the mines. The temperature data will help in determining areas and zones of neotectonic and seismic activation.