ОБ ЭЛЕКТРОПРОВОДНОСТИ МНОГОЛЕТНЕМЕРЗЛЫХ ГОРНЫХ ПОРОД

• Main Authors: Захаренко, Владимир, Краковецкий, Юрий, Парначев, Валерий, Попов, Лев
• Format: Text
• Language: unknown
• Published: Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Национальный исследовательский Томский государственный университет" 2012
• Subjects: ЭЛЕКТРОПРОВОДНОСТЬ; МНОГОЛЕТНЯЯ МЕРЗЛОТА; КРИОПЭГИ; ЭЛЕКТРОРАЗВЕДКА; ВАРИАЦИИ ЭЛЕКТРОМАГНИТНОГО ПОЛЯ; Arctic; Chelyuskin; Norilsk; Ice; khatanga; norilsk; permafrost; Yakutia
• Online Access: http://cyberleninka.ru/article/n/ob-elektroprovodnosti-mnogoletnemerzlyh-gornyh-porod; http://cyberleninka.ru/article_covers/14008118.png

При составлении прогнозной карты геоэлектрических разрезов масштаба 1:2 500 000 было установлено и экспериментально доказано, что горизонты с низким электрическим сопротивлением (30-200 Ом·м) являются не аномальными участками, а имеют широкое площадное распространение в зоне криолитогенеза. Это позволило использовать радиоэлектромагнитные методы в удаленных и слабоизученных районах, в частности на п-ве Челюскин, с целью определения мощности рыхлых отложений. Вариации напряженности радиополя в средних широтах объясняются температурной зависимостью электропроводности древесины, что требует введения при геофизических исследованиях в зимний период температурных поправок к измеренным значениям напряженности радиополя. The bulk of the work was carried out by the integral method of route radio-comparing, allowing to explore large areas for a short time. Measurements of the earth's wave tension were conducted by 16 emitters CB-IR band (160-1000 kHz). The length of individual lines is 100 km to 1130 km. The number of detected frequencies per route varied from 1 to 5, depending on the location of the route that allowed us to obtain a total of 94 curves of the modulus of the attenuation function of the distance. Tests were held by methods of sounding, Ramsey held on the Peninsula Chelyuskin (1986, 1988), in the area Gurievsk (Kemerovo region, 1989), Norilsk (1990), and profiles Norilsk-Khatanga (1988), Sverdlovsk (at present Ekaterinburg) Kamyshlov (1989). Variations in radiofield intensity were studied on rf frequencies of 162-675 kHz. Simultaneously, we measured the temperature of air and soil, as well as the electrical conductivity of the upper part of the geoelectric section by sounding methods, Ramsey and the electrical conductivity of wood in the temperature range from -27 to +27 degrees Celsius. The accumulated experimental material on radiofield intensity variations and variations in intensity of rf conductivity of wood (both hardwood and softwood) became the basis for the solution of the so-called "winter" anomaly in the propagation of medium radio waves in middle latitudes. The work identified and experimentally proved wide distribution of low-resistance (30-200 ohm m) formations in the area of permafrost. The presence of low-resistivity layer allowed to use the method of Ramsey (REMP) (according to another classification SDVR method) at high latitudes to determine the thickness of unconsolidated alluvial deposits in the search for mineral deposits. The drilling of L-210 profile on the Arctic coast of the Peninsula Chelyuskin is given as an example of such work. In 1986 a complex of geophysical methods VES with AB/2 up to 500 meters, two-dimensional electric profiling symmetrical with AB/2 11 and 100 meters, two-frequency electromagnetic profiling at frequencies 16.4 and 19.0 kHz, magnetic prospecting was held here. The specific electrical resistance (resistivity) of the first layer corresponding to the zone of seasonal defrost varies in the range 15-50. 100300 Ohm m. The thickness of this layer varies from 10 to 70 cm. The second horizon is characterized not only by high resistivity, but also by a greater variation of electrical resistance in the sequence (11 000. 89 000 ohm m, with single "bounces" up to 120,000 ohm m). Geologically, this layer corresponds to frozen marine Quaternary sediments, traced over the entire profile. Variability of the resistivity is explained by the varying ice content in these formations, and maximum values correspond to ice interlayers, which are observed in the section. The thickness of the layer varies from 2 to 5 meters. The third layer has the greatest interest: it is characterized by a low impedance of 30-200 Ohm m. Decreased resistance of these rocks is explained by the presence of high salt content. The thickness of these structures is 5-50 m. Work on L-210 profile showed that the low-lying areas of the buried relief are characterized by reduced (absolute) values of the reduced surface impedance phase (φ). The phase of impedance value is close to 45° in those places, where the bedrock is almost out to the surface, which corresponds to a uniform cross-section. At the same time, the reduced modulus of the surface impedance (pef.) in such places has a sawtooth character and a higher value (zone of quartz veins). Radioimpedance measurements in permafrost (Yakutia, Northeast Russia) fulfilled in recent years confirm the wide distribution of areas with low electrical resistance, which can be considered today as an established fact.