Distribution and occurrence of some naturally‐occurring polytypes of molybdenite in Australia and Papua New Guinea

156 samples of naturally‐occurring molybdenite from 87 localities in Australia have been examined to determine the distribution of the hexagonal (2H₁) and rhombohedral (3R) polytypes. 90% of the specimens examined are 2H₁ polytypes, the remainder being 3R and mixtures of 2H₁ and 3R polytypes. The 3R and mixed polytypes are more abundant in porphyry copper deposits or as disseminations, in veins, and in garnet‐quartz pipes in granite. 2H₁ polytypes are the sole modification observed in pegmatites, quart‐pegmatite pipes, simple quartz veins, and skarns.

The highest average concentrations of rhenium are in molybdenite from porphyry copper deposits, quartz porphyry pipes, skarn deposits, garnet‐quartz pipes, and pegmatites. Low concentrations occur in molybdenite which is disseminated or in quartz veins in granite and in quartz or pegmatitic pipes. Molybdenites in which the 2H₁ polytype is dominant have a lower average rhenium content than those with dominant 3R polytype.     

Tectonic Environments of Cenozoic Volcanic Rocks in China and Characteristics of the Source Regions in the Mantle

Extensive volcanism is one of the important features of Cenozoic geology in China.Based on temporal-spatial distribution,the volcanism was associated with three major different geological settings:1)the continental rift basalts in Northeast and North China;2)the tension-fault basalts on the continental margins of Southeast China; and 3) the collision-zone high-K volcanics in the Qinghai-Xizang Plateau and its vicinities.The characteristics of “depletion in the south and enrichment in the north“of the China continental mantle are strongly supported by isotopic evidence.The Cenozoic continental cal characters,into the following geochemical provinces:1)the depleted mantle in South China;2)the primary mantle in Northeast and NorthChina; 3)the hybrid and transi-tional mantle in the region of Shandong ,Anhui,Jiangsu and northern Zhejiang;4)the depleted mantle around the Bohai Bay and the Lower Liaohe River;5)the K-metasomatic enriched mantle in the northern part of Northeast China;and 6)the re-cycled enriched mantle in the ancient subduction zone in the Qinghai-Xizang Plateau and its surround-ings.These geochemical characteristics on a regional scale must be a reflection of the nature of lithosphere evolution.     

Development of Oil and Gas Resources of Russia’s Arctic zone

The article dwells on the problems associated with the development of oil and gas Arctic region of Russia. It also suggests possibilities of their solution based on sociological studies conducted by the authors of representative samples in 2005, 2010 and 2015. Stressing the role and significance of sociological research in the general problem of the circumpolar regions by scientific study, the authors show the need for a sociological diagnosis in the context of different social groups. By doing so, characteristics of social problems inherent to the arctic region and requirements for scientific support of possible technologies is identified.     

Origin and recharge estimates of groundwater in the ordos plateau,People’s Republic of China

Groundwater is a valuable resource in the semiarid Ordos Plateau region where abundant mineral resources, such as coal, natural gas, and halite, are present. With resources development, groundwater demand will increase dramatically. The origin identification and recharge estimates of groundwater are significant components of sustainable groundwater development in the Ordos Plateau. Groundwater and precipitation samples were taken and the isotopic compositions δ²H, δ¹⁸O, and chloride were analyzed to identify groundwater origins and to estimate recharge rates. The δ²H and δ¹⁸O of the groundwater show that the groundwater recharge is of meteoric origin. The chloride mass balance (CMB) method was used to quantify recharge rates of groundwater in the Ordos Plateau, which varies from 2.93 to 22.11% of the effective annual rainfall. Recharge rates estimated by CMB were compared with values obtained from other methods and were found to be in good agreement. This study can be used to develop effective programs for groundwater management and development.     

Metallogeny of deep structures of the Earth’s crust in Southern Sikhote-Alin: Evidence from gravity data

The spatial relations between ore deposits in Sikhote-Alin and deep density inhomogeneities of the Earth??s crust down to a depth of 30 km have been examined. The ore areas and regions show a discrete correlation with the anomalies of the normalized density of the equivalent spherical sources of gravity anomalies at depths of 1 to 2, 4 to 5, 10?C12, and 24 km presumably provoked by magmatic bodies of different compositions. The depth of the magmatic bodies with the intermediate-to-basic composition of the initial magmas and the southeastward-decreasing vertical range of their correlation with the ore regions depend on their structural position. In the case of magmatic bodies of felsic and mixed compositions, the metallogenic specialization of the corresponding ore-magmatic systems is correlated with their inferred vertical range. Tin ore systems are characterized by a smaller vertical range (5?C10 km) of the correlation with density inhomogeneities, whereas tin-tungsten-gold ore systems are marked by a wider range (20?C25 km). Tin-lead-zinc systems occupy an intermediate position (12?C20 km). The ore-controlling role of the boundaries between the lithostructural complexes of the Earth??s crust and the central-type structures in the distribution of deep sources of ore mineralization is shown.     

Club convergence and spatial distribution dynamics of carbon intensity in China’s construction industry

Climate change caused by carbon emissions continuously threatens sustainable development. Due to China’s immense territory, there are remarkable regional differences in carbon emissions. The construction industry, which has strong internal industrial differences, further leads to carbon emission disparity in China. Policymakers should consider spatial effects and attempt to eliminate carbon emission inequality to promote the sustainable development of the construction industry and realize emission reduction targets. Based on the classic Markov chain and spatial Markov chain, this paper investigates the club convergence and spatial distribution dynamics of China’s carbon intensity in the construction industry from 2005 to 2014. The results show that the provincial carbon intensity in the construction industry is characterized by “convergence clubs” during the research period, and very low-level and very high-level convergence clubs have strong stability. Moreover, the carbon intensity class transitions of provinces tend to be consistent with that of their neighbors. Furthermore, the transition of carbon intensity types is highly influenced by their regional backgrounds. The provinces with high carbon emissions have a negative influence on their neighbors, whereas the provinces with low carbon emissions have a positive influence. These analyses provide a spatial interpretation to the “club convergence” of carbon intensity.     

Sources and behavior of arsenic and trace elements in groundwater and surface water in the Poopó Lake Basin,Bolivian Altiplano

Water management in semiarid and arid catchments such as the Poopó Lake Basin requires improved understanding of the complex behavior of the various contaminants, which affect the drinking water quality and considered as crucial for sustainable development of the region. Mechanisms of arsenic (As) release in the surface and groundwater were studied. Hydrochemical data for surface water (4 samples) and groundwater (28 samples) were collected in a small watershed in the Poopó catchment at the highland of the Bolivian Andes (Altiplano). All of them show high electrical conductivity values and moderately oxidizing conditions. The surface water contains high concentration of sulfate and the trace elements As, Zn and Pb in the zone affected by acid mine drainage. There is a large variability of the concentration of As and of the trace elements in the groundwater in the five different regions within the Poopó catchment. The metal concentrations sensitive to changes of redox state and results of speciation modeling suggest that As (V) is a predominant aqueous species, which conforms to the prevailing oxidizing conditions in the shallow groundwater environment. Two generalized trends for As distribution were identified in groundwater: (a) high concentrations are found in the arid zone (100–250 μg/L) in the southern (region III) and in the northwestern (region V) regions, and (b) low concentrations (<50 μg/L) are found in the remaining part of the basin (region I, II and IV). However, the spatial distribution within these regions needs to be investigated further. A conclusion from the present study is that there are multiple sources of As as well as other trace elements (such as Cd, Mn and Zn) in the Poopó Lake Basin. Among the sources and the processes which led to the mobility of As and other trace metals in the region are: (a) weathering of sulfide minerals, (b) oxidation of pyrite and/or arsenopyrite in mineralized areas and (c) desorption from hydrous ferric oxide (HFO) surfaces. In non-mining areas, volcanic ash is suggested to be a significant source of As.     

Magmatic Source Composition and Magmatism of the Volcanic Rocks in the Area of Kuruktag, Southern Xinjiang

1. Geological setting The terrane of Kuruktag lies in the north-eastern margin of the Tarim Basin and is a faulted marginal uplift of the basin. In the terrane, there occur extensively Dagelagebulake Group and Xinditage Group of Archaean-Paleoprotozoic metamorphic sequences overlain by Sinian-Cambrian sequences (Geological and mineral bureau of Xingjiang ulger atonomous region, 1993). The sedimentology of the Sinian-Cambrian strata have been studied (South Xinjiang petrollum exploratio…     

Scenario Prediction of China’s Oil Resource Demand in 2020-2030

Oil plays an important role in ensuring national energy security. It is of great significance for China’s energy policy-making to predict the future oil demand scientifically. Combined with the grey correlation analysis and combination model of ARIMA-BP neural network, data on six driving variables of China’s GDP, international oil price, energy consumption per unit GDP, industrial structure, urbanization rate and oil production in 1999-2018 were selected to predict China’s oil demand under different scenarios in 2020-2030. The results show that the selected driving variables are highly correlated with China’s oil demand, and the combined model is more accurate than the single model. From 2020 to 2030, China’s oil demand and import will continue to increase, but the growth rate will gradually slow down. Under the three scenarios, the predicted average oil demand in 2020, 2025 and 2030 will be 675.7703 million tons, 732.2725 million tons and 760.8155 million tons, respectively; the predicted average external dependence in 2020-2030 will be 76.19%, far exceeding the international warning line of 50%. The contradiction between China’s oil supply and demand will be more acute, and accordingly, some policy suggestions were put forward.     

Protons of Radiation Belts as a Source of Hydrogen in the Earth’s Atmosphere

Doklady Earth Sciences - A scenario is proposed for replenishing the Earth’s exosphere with atomic hydrogen of cosmic origin. An assessment was made, and the coincidence of the total atomic...     

Accumulation Characteristics of Tight Sandstone Oil below Source Rocks and Its Major Controlling Factors：Fuyu Oil Layer in Da’an Area in Songliao Basin, NE China

<正>1 Introduction Tight sandstone oil generally refers to the oil accumulated in tight sandstone reservoir rocks,with insitu permeability less than 0.1×10~(-3)μm~2(or surface permeability lower than 1×10~(-3)μm~2).Under normal conditions,there is no oil natural capacity in the well,or natural capacity is lower than the threshold of industrial     

Abundance and Distribution of Reef-Associated Fishes Around Small Oil and Gas Platforms in the Northern Gulf of Mexico’s Hypoxic Zone

Oil and gas platforms (platforms) provide high-relief habitat in the northern Gulf of Mexico’s hypoxic zone that are important to associated fishes. Hypoxia develops near the bottom and reef-associated fishes utilize vertical structure in the well-oxygenated waters overlaying hypoxia. A video array was used to profile the water column and to estimate abundances and depth distributions of fishes before, during, and after summer hypoxia at platforms experiencing intense (seaward) and mild hypoxia (shoal). Gray snapper abundance increased at shoal platforms (10× greater after vs. before the hypoxia season), while abundance remained stable at seaward platforms. However, there was no significant relationship between gray snapper abundance and oxygen concentrations. Sheepshead, Atlantic spadefish, blue runner, and Atlantic bumper abundances varied throughout the summer, but there was no significant effect of hypoxia. Occupation of bottom waters by fishes was consistent throughout the study period at shoal platforms, but fishes were rarely observed in the bottom 3 m and congregated in the water immediately above the hypoxic layer when hypoxia was present at seaward platforms. Nevertheless, patterns of fish abundances were not driven by the presence or absence of hypoxia. The vertical dimension of platforms is a unique and key aspect of their ecological value, especially in the hypoxic zone, and should be considered for artificial reef management.     

The Source of Ore Fluids and Sm–Nd Age of Siderite from the Largest Bakal Deposit,Southern Urals

Geology of Ore Deposits - Based on Sm–Nd data, a crustal source of iron-ore fluid was substantiated and the probability of age estimation for hydrothermal–metasomatic siderite of the...     

Vertical distribution, stability and evolution of groundwater composition in granite suitable for storage of spent nuclear fuel

Granite with extremely low permeability has been selected to host a repository of spent nuclear fuel in the Czech Republic. Three boreholes were drilled in a test site of the Podlesi granite stock in the Krusne hory Mts. The holes were located 10 m apart. After hydraulic tests, four sections in one of the boreholes were separated by packers at depth of 69-111, 111-161, 161-220 and 220-300 m. Samples of groundwater from each section were periodically collected for chemical and isotopic analysis. Groundwater from fractures in the granite stock does not belong to a single and uniform groundwater body in spite of that the granite is chemically and mineralogically homogeneous. There are three water bodies, which are only partly hydraulically connected. They are： （1） The groundwater in the oxidation zone to a depth of about 111 m. （2） The groundwater of the zone of hydrolysis of alumosilicates from 111 to 220 m. （3） The groundwater of the zone of hydrolysis of alumosilicates below the depth of 220 m from a different fracture system than the water from the above sections. The total dissolved solids of water increase with depth. The Ca-SO4 component predominates in the near surface water body while Na-HCO3 component predominates in the two deeper water bodies. Water from the oxidation zone contains higher concentrations of iron and other trace metals. The chemical composition of water in the three water bodies changed during the 14 months of sampling. No steady state was reached during this time. The changes displayed systematic trends. The ratio Ca/Na increased and the ratio HCO3/SO4 decreased with time in the shallow water body. In contrast, the ratio CafNa decreased and HCO3/SO4 fluctuated without an obvious trend in the deeper water bodies. An unusually high concentration of dissolved organic carbon （DOC） was found in the lowest section of the test borehole. The concentration of DOC was 150 mg/L at the beginning of sampling. The isotopic composition was δ^13C=-27.6 ‰. The concentration of DOC dropped both towards the surface and with time.     

Source,transport, and fate of rhenium,selenium, molybdenum,arsenic, and copper in groundwater associated with porphyry–Cu deposits,Atacama Desert,Chile

We collected groundwaters in and around a large (313 Mt at 1.08% Cu and 0.3% cutoff) undisturbed porphyry copper deposit (Spence) in the hyperarid Atacama Desert of northern Chile, which is buried beneath 30–180 m of Miocene piedmont gravels. Groundwaters within and down-flow of the Spence deposit have elevated Se (up to 800 μg/l), Re (up to 31 μg/l), Mo (up to 475 μg/l) and As (up to 278 μg/l) concentrations compared to up-flow waters (interpreted to represent regional groundwater flow). In contrast, Cu is only elevated (up to 2036 μg/l) in groundwaters recovered from within the deposit; Cu concentrations are low down gradient of the deposit. The differential behavior of the metals/metalloids occurs because the former group dissolves as anions, enhancing their mobility, whereas the base metals dissolve as cations and are lost from solution most likely through adsorption to clay surface exchange sites and through formation of secondary copper chlorides, carbonates, and oxides. Most groundwaters within and down-flow of the deposit have Eh–pH values around the Fe^II/Fe^III phase boundary, limiting the impact of Fe-oxyhydroxides on oxyanions mobility. Se, Re, Mo, and As are all mobile (with filtered/unfiltered samples ～ 1) to the limit of sampling 2 km down gradient from the deposit. The increase in ore-related metals, metalloids, and sulfate and decrease in sulfate–S isotope ratios (from values similar to regional salars, + 4 to + 8‰ δ³⁴S_CDT to lower values closer to hypogene sulfides, + 1 to + 4‰ δ³⁴S_CDT) is consistent with active water–rock reactions between saline groundwaters and the Spence deposit. It is likely that hypogene and/or supergene sulfides are being oxidized under the present groundwater conditions and mineral saturation calculations suggest that secondary copper minerals (antlerite, atacamite, malachite) may also be actively forming, suggesting that supergene and exotic copper mineralization is possible even under the present hyperarid climate of the Atacama Desert.     

Heat contamination in groundwater sourced from heat pump for heating in Bratislava (Slovakia)’s historic centre

The aim of the study is to evaluate the warming effect (thermal contamination) of city centres with high building density. This phenomenon has a number of scientific and practical implications. The case study was conducted in Bratislava (Slovakia), in the geological environment of alluvial gravels of the Danube River, where a permanent warming of the subsurface in the city centre is experienced, which is mainly affected by high building density and underground utilities. Thanks to this thermal contamination, the heat pumps efficiency is greater in winter, while in summer, their effectiveness is lower. Economically, this negative phenomenon in the case of heat pumps has a positive effect, since it increases energy efficiency during the heating period. This phenomenon is not universal and depends on the specific boundary conditions of the geological settings and hydrogeological conditions.     

Study on vertical distribution and activity factor of P forms in sediments of three urban shallow lakes in People’s Republic of China

The vertical variation of P forms in sediments of urban shallow lakes in China, Xuanwu Lake, Daming Lake and Mochou Lake, were sequentially extracted and measured with the method of SEDEX. The results indicated the TP content in the sediment profiles ranged from 371.94 to 777.25 mg kg⁻¹ for Xuanwu Lake, 1,308.14 to 4,632.63 mg kg⁻¹ for Daming Lake, and 995.49 to 1,860.71 mg kg⁻¹ for Mochou Lake. The results of sequential extraction showed that Ca-P and Fe-P were the main fractions. Meanwhile, the proportions of Bio-P to TP were 35.24% for Xuanwu Lake, 29.57% Daming lake, and 25.26%, for Mochou Lake, indicating a high potential of P releasing. The content of Bio-P was significantly and positively correlated with TP (r = 0.978, P < 0.01). Lake hydrations conditions played an important role in the distribution and contents of Bio-P and TP. In the region with macrophytes, the contents of TP and Bio-P were relatively low. Physicochemical properties of sediments were significantly related to the fraction distribution and P contents, and might play an important role in controlling P activity and mobility. Moreover, Fe showed an evident influence on P fraction and the ratio Fe/P might be good indicator to the contents and composition of active P in sediments.