ГЕОХИМИЯ ПОДЗЕМНЫХ ВОД РАЙОНА БАКЧАРСКОГО ЖЕЛЕЗОРУДНОГО МЕСТОРОЖДЕНИЯ (ТОМСКАЯ ОБЛАСТЬ)

• Main Authors: Лепокурова, Олеся, Иванова, Ирина
• Format: Text
• Language: unknown
• Published: Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Национальный исследовательский Томский государственный университет" 2011
• Subjects: ГЕОХИМИЯ ПОДЗЕМНЫХ ВОД; СИСТЕМА «ВОДА ПОРОДА»; БАКЧАРСКОЕ ЖЕЛЕЗОРУДНОЕ МЕСТОРОЖДЕНИЕ; taiga
• Online Access: http://cyberleninka.ru/article/n/geohimiya-podzemnyh-vod-rayona-bakcharskogo-zhelezorudnogo-mestorozhdeniya-tomskaya-oblast; http://cyberleninka.ru/article_covers/13990294.png

Приведены результаты изучения химического состава подземных вод района Бакчарского месторождения, а также результаты расчета равновесий в системе «вода порода». Показано, что воды относятся к кремнистому кальциево-железистому геохимическому типу вод и способны образовывать ассоциацию вторичных железистых минералов, наблюдаемую в осадочных железорудных месторождениях типа Бакчарского. This article presents the results of studying the chemical composition of the Bakchar iron ore deposit area groundwater, located 200 km northwest of the city of Tomsk in poorly rendered habitable taiga swampy area. Groundwater is in five water-bearing horizons. Almost universally, it contains elevated and high concentrations of iron 30 mg/l, as well as manganese, organic matter; it is depleted of free O2. The ground water from the surface of the first three waterbearing horizons (QII tb P3 lt, P3 nm, P2-3 jur) lies in the sand and gravel deposits with clay, loam and lignite layers. They are fresh (salinity from 0.4 to 0.7 g/l, an average of 0.6 g/l), neutral and alkalescent (pH 6.8-7.8), hard (5-9.4 meq/l), hydrocarbonate calcium and calciummagnesium. These waters are Fe-enriched up to 10 mg/l, the average of 4 mg/l, Mn-enriched up to 2 mg/l. The groundwater of the Upper Cretaceous deposits includes two water-bearing horizons confined to sandy-clay formations of the Gankovskaya (K2 gn) and Ipatovskaya (K1-2 ip) suites. The water of the Gankovskaya formation is fresh, with higher salinity (0.6-1.2 g/l). There is a shift of water from hydrocarbonate calcium to sodium bicarbonate. This causes the large variation in the values of hardness (from 0.3 to 9.6 meq/l). In comparison with the higher-lying waters, they have higher alkalinity (pH 6.8-8.6). The content of iron in the groundwater, on the contrary, decreases to 2.9 mg/l on the average, but it is still high. The thermodynamic calculations of equilibriums in the water-rock system were made. It is shown that all the water is not in equilibrium with the primary water-bearing rocks minerals: feldspar, muscovite, biotite, garnet, pyroxene, hornblende, epidote, chlorite, and many others. However, the studied water is in equilibrium with montmorillonite, illite, kaolinite and other clays, and calcite and siderite. Therefore, under these conditions the minerals of the first group dissolve actively, especially pyroxene, epidote and hornblende, unstable under these conditions and, therefore, being the source of iron and other elements. Then, as a result of incongruent dissolution, secondary minerals form, connecting parts of Si, Al, Ca, Mg, Na, K and Fe. According to the accepted classification of S.L. Shvartsev, according to which waters are named by the composition of the elements that bind the crystal lattice of secondary minerals formed in this system, the groundwater of the Bakchar iron deposit is the siliceous calciumiron geochemical type of water. It can form an association of secondary iron minerals observed in the sedimentary iron-ore deposits of the Bakchar type.