Geophysical search for fragments of the Sterlitamak meteorite

Relevance is determined by the fact that meteorites are of great importance for the direct study of the substance of the Universe, therefore, when new meteorites fall, maximum efforts are made to detect them and study the conditions of the fall. The purpose of the work is to further study the meteorite crater and search for large fragments of the Sterlitamak meteorite not found at the first stage of study using geophysical methods. The story of the fall and searches for the main fragment of the Sterlitamak meteorite, which fell on August 17, 1990 at 23 h 25 min, on the field of the Sterlitamak state farm is described. When it fell, a crater with a diameter of 10 m and a depth of 4 m was formed. The fall was accompanied by a bright glow and thunderous rumbles. A glow was observed over the crater in the dark. A high-speed searching for the meteorite was organized by collecting meteorite debris around the crater. At the same time, a mine detector was used. The crater was excavated with an excavator to a depth of 18–20 m. Fragments weighing 6.6; 3.06; 0.875; 0.363 kg were found. A year later, the main body weighing 315 kg was accidentally found in the dumps. Chemical analysis of the substance showed that it is an iron-nickel meteorite, 98% of the thickness are the minerals kamacite, tenite and schreibersite. Results. In 2014–2015, the authors carried out magnetic surveying around the crater and on the ice of the lake, which was formed at the excavation site, in order to search for fragments of the meteorite, which were probably missed at the initial stage. Maps of the magnetic field and terrain of the crater are given. Magnetic anomalies are identified, which are presumably associated with new fragments of the meteorite. The probable depths of the meteorite fragments are 2–4 m. In-depth sections of the magnetization for these anomalies obtained by the method of magnetic tomography, are given, as well as the results of a surface survey of the dump area using a metal detector. Weakly magnetic samples were found containing sprayed metal and metal balls with a diameter of 0.5–1.0 mm. These samples originally formed a zone of impact metamorphism, which was destroyed by excavation operations. It is shown that the territory is promising for searching for new large fragments of the meteorite and studying the processes of impact metamorphism. It is planned to further study the crater by means of electrical exploration and GPR sounding.