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The Verkhoyansk–Kolyma fold-thrust belt is an important metallogenic structure of northeastern Russia. Based on irregularly distributed gold mineralization within this belt two large ore-placer districts are distinguished: the Upper Indigirka district (UID) in the northwest and the Central Kolyma district (CKD) in the southeast. The gold grade in these areas is largely provided by a large fault structure—the ore-controlling Adycha–Taryn deep fault. Along the entire length, this fault changes its kinematic characteristics, from an overthrust reverse fault in the north to a strike-slip reverse fault (Tenka fault) in the south. Such a change of the fault kinematics laterally, in the principal ore-controlling structure, is reflected in the structure of specific ore-bearing faults in ore areas, as we have shown on the example of the Degdekan (CKD) and Drazhnoe (UID) deposits. In the Degdekan deposit, synthetic overthrust reverse faults, which control large-volume deposits of relatively poor ores, are ore-bearing, and, in the Drazhnoe deposit, opposite strike-slip faults contain small-size, superimposed rich ore bodies. The change of ore-bearing faults in different ore areas is explained by their position in the changing stress field that formed at different stages of geodynamic development: (1) associated with the collision of the Kolyma–Omolon superterrane and the Siberian craton and collision with the Alazeya arc (early ore mineralization of the Upper Indigirka ore district) and the Uda–Murgal arc (early disseminated pyrite mineralization of the Central Kolyma ore district) and (2) collision with the Chukchi microcontinent and re-activation of earlier faults (the main gold-sulfide-quartz mineralization of the Yana–Kolyma metallogenic belt). [ABSTRACT FROM AUTHOR]

Integrated structural geological, minerogenic, and metallogenic studies with allowance for previous topical surveying, geological mapping and prospecting, and mineral exploration data has revealed that Upper Paleozoic and Early Mesozoic tectonomagmatic structures are widespread in the Selenga ore district. They are associated with the evolution of the transregional Upper Paleozoic Selenga–Vitim rift-related volcanoplutonic belt and the formation of the Early Mesozoic West Transbaikalian region of intraplate magmatism. Late Paleozoic–Mesozoic igneous activity accounts for the bulk of mineable mineral resources in the Selenga ore district concentrated inside and outside the ore clusters (Kunalei, Kizhinga, Cheremshana–Oshurkovo, Tashir, etc.). It is demonstrated that the main mineable metals in the district are molybdenum and beryllium, which determine the minerogenic specificity of the ore district. New compositional characteristics of the Upper Paleozoic and Early Mesozoic intraplate magmatic complexes and the associated mineral deposits (Mo, Be, Ti, quartz, fluorite, and apatite ores), as well as other promising gold, uranium, and REE–Ba–Sr ore occurrences were obtained. The geodynamic settings of their formation and the ages of the main ore-forming processes have been established; the viability of the mining industry in the Selenga ore district and the feasibility of involving its ore potential in the district's economic modernization program have been assessed. [ABSTRACT FROM AUTHOR]

Abstract Baiyin (Gansu Province, China) is a heavily industrialized city with non-ferrous metal mining, ore dressing, and chemical production. The surrounding district has suffered from serious heavy metals (HMs) contamination over half a century. In this study, a Pb isotopic approach was adopted to trace the sources of HMs and explore the environmental behaviors of HMs in the area surrounding Baiyin. HMs concentrations in topsoil showed a clear decrease as the distance from the ore district increased, which suggested that atmospheric transportation is one of the main pathways of HMs dispersal. The Dongdagou irrigation area was an exception where contaminated water from Dongdagou had been used for a long time. The plots of 206Pb/207Pb vs. 208Pb/206Pb and 1/Pb vs. 206Pb/207Pb from the topsoil samples could be described in terms of a binary mixing model with the two average 206Pb/207Pb end-members being (1) the mining and smelting activities (1.1494) and (2) the soil background (1.1992). The relative anthropogenic contribution quickly decreased from 88.3% in the ore district to 30.6% in the Yellow River irrigation area. These results suggested that HMs in the Baiyin District were mainly contributed by anthropogenic mining and smelting activities. The isotope ratios of 206Pb/207Pb in the sediments maintained a consistent low level from the ore district to the Yellow River irrigation area, thereby suggesting that HMs from anthropogenic sources could also be transported over a long distance in the river systems. Moreover, the positive correlation between S content and HMs concentrations in topsoil and sediment confirmed that the HMs mainly originated from the sulfide deposits and smelters. Graphical abstract Unlabelled Image Highlights • Pb isotopes are used to trace the source of HMs in Baiyin. • Mining, smelting, and sewage irrigation are responsible for HMs contamination in Baiyin area. • Anthropogenic contribution to HMs contamination was calculated using 206Pb/207Pb. • Make an insight into the transport and accumulation of HMs around the mining area • Provide a scientific basis for the control, prevention, and remediation of HMs pollutions [ABSTRACT FROM AUTHOR]

Based on complex structural, rheological, and metallogenic studies, taking into account the results of earlier subject-specific, prospecting, mapping, and exploration works, it has been established that the geological structure of the district was caused by the ensimatic evolution of the Vendian-Early Paleozoic Dzhida island-arc system, in which oceanic and island-arc complexes served as a melanocratic basement for Late Paleozoic-Mesozoic active within-plate (riftogenic) processes, which gave rise to the formation of ore deposits and occurrences of strategic mineral commodities (Mo, W, Au, Pt, Ag, and rare elements, including REE). Mantle plumes and flows of deep-seated transmagmatic solutions (ore-forming fluids) played a critical role in these processes, the significance of which increases in upper crustal swarms of dikes and fault systems. The forecasts and development prospects of the Dzhida ore district envisage the expansion of geological prospecting and exploration, scientific research, and technological testing of ore for insight into strategic mineral commodities, as well as reanimation of mining within the areas of the Dzhida's large territorial and industrial complex (TIC) in eastern Siberia. [ABSTRACT FROM AUTHOR]

Two parallel NW-trending magnetotelluric (MT) profiles were placed perpendicularly to the main structures of the Anqing-Guichi ore district, one of the seven ore districts in the middle–lower Yangtze River metallogenic belt of eastern China. In October–December 2013, the MT data acquisition was carried out at 117 sites with 0.5–1 km site spacing. The MT data has a good quality in the frequency range between 320 and 0.01 Hz. The dimensionality analysis and 2D resistivity inversion results indicate that: (1) the deep of the ore district with three-dimensional structural characteristics, but two-dimensional structural characteristics for shallow; (2) there is a clear correlation between resistivity and the main geological units of the ore district, as well as correlation with mapped surface faults; (3) the Gandan deep fault (GDF) and Jiangnan deep fault (JNF) extend from the surface to 10 km deep, with dip of NW45°, and dip angles larger than 60°. A series of NE-trending acidic intrusive rocks were controlled by the GDF. [ABSTRACT FROM AUTHOR]

Statistical data are given on the thermal conductivity of rocks in the Komsomol’sk ore district (Khabarovsk Territory). The regularities of variations in the thermal-conductivity and thermal-inhomogeneity factors of the studied types of rocks are considered in relation to their mineral composition, texture, structure, and degree of metasomatic alteration. Thermophysical sections of the studied mineralized zones are presented. The conclusion is substantiated that the thermal properties of rocks are highly informative and detailed thermophysical studies of sections might be useful for their lithological subdivision. © 2015, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved. [ABSTRACT FROM AUTHOR]

The pollen morphology of Aconogonon angustifolium (Pall.) Hara. and Papaver nudicaule L. from Sherlovogorskii ore district of Zabaikalskii krai was considered depending on toxic agent contents in flowers and flower buds. It was determined that the pollen polymorphism rate under the conditions of elevated toxicant contents was higher in Papaver nudicaule L. than in Aconogonon angustifolium (Pall.) Hara. Morphological abnormalities of Papaver nudicaule pollen can be considered as an indicator of the environmental quality. [ABSTRACT FROM AUTHOR]

Abstract: Five intersecting reflection seismic profiles were shot over the Lu–Zong volcanic basin, one of the seven ore districts in the middle and lower Yangtze River Metallogenic Belt in east China. The seismic data reveal diversified reflective patterns in the upper crust, which are interpreted as horsts and grabens in general. The middle crust presents both thrust related structures and boudinage and pinch-and-well structure on different profiles, suggesting a strong structural heterogeneity, which developed due to a change from compressional to extensional movement. Below the central part of a volcanic basin, the lower crust shows an obvious reflective anisotropy both at the crust–mantle and the brittle–ductile transition in the crust. This feature may be explained by magma system emplaced along a NE-trending fault or weak zone at different depths. The Tan-Lu fault zone is present as a northwest-dipping fault extending to the middle crust. The lower crust beneath the Tan-Lu fault and peripheries is possibly of Dabie affinities. The Lu–Zong volcanic basin is clearly defined as an asymmetric graben with master faults on both the east and north flanks. A contrasting reflection character suggests a division of the basin into northern and southern parts separated by a concealed fault. The relatively thin volcanic sequences, inferred to be 800–1000m in thickness, cover Triassic and Paleozoic sequences at depth, that provide an exploration target in the northern part for deep porphyry and skarn deposits. The dominant deformation reflects NW–SE-oriented compression and extension formed during the Yanshanian orogenic episode. The contraction deformation is characterized by thrust faults with imbrication of crustal slices, whereas the extension deformation is featured by normal faults, regional detachments and basins. Underplating of mantle-derived magma and a multi-layer magma intrusion model are proposed to explain both seismic features and the NE-striking Lu–Zong volcanism and igneous intrusions in the region. [Copyright &y& Elsevier]

The Central Aldan ore district (CAOD) is considered as an integral ore-forming magmatogenic system (IOMS) consisting of ore-forming systems of different ranks. The epicenter of the IOMS is occupied by the main (head) magma conduit expressed at the present erosion level as the Western El’kon magmatic area. The systematic radial position of the main ore-bearing zones relative to the IOMS’s epicenter is considered as an indication of their relation to the head magma conduit. There are daughter ore forming systems of the first order (the El’kon (EOS), Kuranakh (KOS), and Tommot (TOS)), as well as ore systems of higher orders. Ore zoning distinctly observed in the EOS and KOS and outlined in the TOS consists of the change of the gold or molybdenum (EOS) mineralization for gold-uranium mineralization toward the head of the magma conduit. The ore objects are derivatives of magmatic reservoirs (chambers) located at different levels of the staged magmatogenic system. The gold and uranium mineralization is mainly related to the pervasive potassic metasomatism. The CAOD is considered as a superproductive area promising for revealing new large ore deposits and recommended as a priority object for large scale gold and uranium exploration. [ABSTRACT FROM AUTHOR]