—Results of a geochemical study of brines and oil occurrences in the Udachnaya kimberlite pipe are presented. Like other intrusions in the Daldyn–Alakit diamondiferous region, this diamond deposit is a unique cryohydrogeologic microstructure differing from the host sedimentary rocks and other diamond pipes of the Yakutian diamond-bearing province. Two waterlogged zones distinguished in the section of orebodies at the explored depths of the deposit correspond to the upper and middle Cambrian aquifers. Predominantly acidic (average pH = 5.5) Cl–Ca and Cl–Ca–Na brines with TDS from 94.3 to 391.3 g/dm3 are widespread within the orebodies and host rocks. The brine mineralization and contents of major salt-forming components increase with depth, to the horizon at the -365 m elevation, where TDS reaches 391 g/dm3, while below, at the –650 m level with noted hydrogeochemical-field inversion, TDS is 253 g/dm3. The mineralization of Cl–Ca, Cl–Ca–Na, Cl–Ca–Mg, and Cl–Ca–Mg–Na brines in the upper Cambrian rocks varies from 102.9 to 192.9 g/dm3, and the pH values, from 4.9 to 6.2, averaging 5.6. Among the microcomponents, the highest average concentrations (mg/dm3) are found for Br1292.8 > S875.7 > Sr453.7 > Fe79.7 > Li53.4 > B32.7 > I13.3 > Si10.8 > Mn6.4 > Se3.6 > Rb2.3. The values of genetic coefficients vary widely: The rNa/rCl coefficient ranges from 0.18 to 0.31; rCa/rMg, from 1.03 to 3.60; Ca/Cl, from 0.2 to 0.3; and the integrated metamorphism index S (according to S.L. Shvartsev) varies from 193 to 277. The middle Cambrian rock complex, containing more saline brines, has been examined in much more detail. It hosts Cl–Ca, Cl–Ca–Na, Cl–Ca–Mg, and Cl–Na–Mg brines with TDS from 94.3 to 391.3 g/dm3 and high average concentrations (mg/dm3) of microcomponents: Br2224.9 > Sr1024.9 >S500.1 > B202.9 > Li147.1 > Fe97.0 > I33.2 > Rb11.4 > Si9.6 > Se9.5 > Mn3.6 > Ni1.7. As compared with brines in the overlying rocks, the middle Cambrian brines show a wider variation in element ratios: rNa/rCl from 0.14 to 0.34, rCa/rMg from 0.66 to 9.71, and Ca/Cl from 0.03 to 0.45. These brines are also characterized by a significantly higher metamorphism grade, which is indicated not only by the rNa/rCl and rCa/rMg ratios but also by the S index varying from 278 to 316. The composition of stable isotopes δD and δ18O) and dissolved inorganic carbon δ13C) of the brines was investigated. The studied waters are assumed to be of sedimentary–metamorphic origin. Their isotopic composition reflects the climatic conditions existing at the time of their burial, which were probably aggravated by the contribution of the oxygen isotope exchange with water-bearing rocks. The δ13C values of carbon dioxide dissolved in water allow an inference about its biogenic origin. The biogenic carbon isotope exchange is governed by the relationship between methanogenic and SMT processes. Analysis of the 87Rb/86Sr and 87Sr/86Sr isotope ratios of the studied brines has revealed affinity between the isotopic compositions of waters in the Cambrian deposits and in ancient seawaters. The mass chromatograms of saturated-hydrocarbon (HC) fractions show at least two individual types of oils and malthas (naphthides). The third variety resulted from their mixing at different stages of migration. The fourth is from the contact zone; it changed during the explosion of kimberlites. The first, most common, type of naphthides (“postexplosive”) is similar in all geochemical parameters to oils from the Nepa–Botuobiya anteclise, in particular, to those from the Mirnyi arch. Oils of the second (pre-explosive) type are found only in the Udachnaya Formation, within the depth range 1130–1430 m.

Впервые приводятся результаты изучения распределения 238 U, 232 Th, 226 Ra и 222 Rn в природных водах Новосибирской городской агломерации. Особенности гидрогеологического строения предопределили существующую гидравлическую взаимосвязь водоносных комплексов четвертичных, неогеновых и палеогеновых отложений, верхнедевонско-нижнекаменноугольных пород и верхнепалеозойских гранитов. По химическому составу установлено 25 химических типов вод при доминировании HCO3 Mg-Ca, HCO3 Na-Mg-Ca и SO4-HCO3 Na-Mg-Ca с величиной общей минерализации от 127 до 1848 мг/дм 3 и содержанием кремния от 0,14 до 11,77 мг/дм 3. Они характеризуются рН от нейтральных до щелочных (6,9-9,5). Величины Eh варьируют от восстановительных-157 мВ (O2 раств. = 0,3 мг/дм 3) до окислительных +280 мВ (O2 раств. = 19,4 мг/дм 3). Концентрации природных радионуклидов в водах составляют (мг/дм 3

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The geochemical features of 22 deposits and manifestations of radon waters in the south of Siberia (some of them for the first time) are considered. The studied waters are very diverse in terms of gas and chemical composition, total mineralization, geochemical parameters of the environment, and temperature. Three groups of radon waters have been established according to the Eh value: oxidizing conditions, transitional and reducing. Due to the wide variety of waters in terms of chemical composition, some of the studied objects belong to several groups at once, for example, the Choigan natural complex, the Skalinsky, Novobibeevskoye, and Sedova Zaimka manifestations. The concentrations of natural radionuclides are (mg/dm): U (3.68∙10 - 1.40), Th (4.04∙10 - 2.16∙10). The activity of dissolved radon (Rn) varies from 4 to 2257 Bq/dm. The Th/U ratio varies from 2.63∙10 to 26, and its maximal values were detected in ultrafresh, thermal, alkaline waters with reductive geochemical medium in which thorium possesses increased migration capacity. Quite contrary, uranium migrates in the oxidative geochemical setting.

This study is relevant for obtaining the first geochemical data (including information on radionuclides) on the drainage waters of developed and flooded quarries in the eastern areas of the Novosibirsk Region. The objective of the study was to identify the features of the chemical composition of drainage waters (a wide range of chemical elements from Li to U). The study was carried out by titrimetry, ion chromatography and mass spectrometry with inductively coupled plasma in a laboratory setting at the Hydrogeochemical Problem Research Laboratory (PNIL GGH) of the Engineering School of Natural Resources of Tomsk Polytechnic University (IShPR TPU). Measurements of 222Rn in waters were carried out at the Alfarad Plus facility of the Laboratory of Siberian Sedimentary Basins Hydrogeology of the A. A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences (INGG SB RAS). The data were divided into homogeneous geochemical populations using the coefficients Ca / Na, Ca/ Mg, Ca / Si, Mg/ Si, Na / Si. The chemical composition of the studied objects was found to be highly diverse. The dominant waters have the chemical formula SO4-HCO3 / Na-Mg-Ca with a TDS (total dissolved solids) of 400 to 700 mg/dm3. Three geochemical groups of waters were identified. The first is represented by drainage waters of the developed rubble stone quarries, the second includes facilities of the Gorlovka coal basin, and the third refers to abandoned flooded quarries. The first group is characterized by oxidizing conditions with Eh varying over a wide range from +84.6 to +261.0 mV, pH from 6.9 to 8.6, and O2dissoived from 3.43 to 14.39 mg/dm3. The radionuclide concentrations are (mg/dm3): 238U 9.30 • 10-3 - 1,40; 232Th 1,00 • 10-6 - 2,16 • 10-3; 222Rn activity varies from 1 to 572.5 Bq/dm3. The 232Th / 238U ratio ranges from 4.20 • 10-5 to 2.69 • 10-3 with an average of 8.40 • 10-4. The second group has a smaller Eh variation range of +133.2 to +199.6 mV, pH from 7.5 to 8.5, and O2dissolved from 6.81 to 10.43 mg/dm3. The radionuclide concentrations vary in the following ranges (mg/dm3): 238U 2.26 • 10-3 - 2.90 • 10-2; 232Th 7.5 • 10-6 - 5.57 • 10-4. The 232Th / 238U ratio ranges from 8.37 • 10-4 to 4.80 • 10-2 at an average of 9.54 • 10-3. The third group is also characterized by an oxidizingizing geochemical environment with Eh +131.3 - +250.0 mV, pH from 6.9 to 8.8 and O2dissolved from 4.00 to 16.59 mg/dm3. The radionuclide concentrations are (mg/dm3): 238U 3.00 • 10-4 - 2.74 • 10-2; 232Th 1.65 • 10-6 - 1.15 • 10-5; 222Rn activity varies from 2 to 31 Bq/dm3. The 232Th/ 238U ratio ranges from 2.36 • 10-4 to 1.02 • 10-3 at an average of 6.25 • 10-4. Overall, the 232Th / 238U ratio of the studied waters indicates their uranium nature of radioactivity. The data obtained indicate a slight impact of the drainage water discharge from the abandoned quarries on the environment.