Rear Zone Research Articles

New data on the geological structure and zonality of the Vorontsovka gold field in the Northern Urals

Spatial distribution of gold, copper, and iron ore deposits in the Northern Urals with the largest Turya-Auerbakh ore region is controlled by north-west trending linear zones of a probably fault nature. The influence has been demonstrated of regional factors (including the tectonic, magmatic, and geochemical ones) favoring formation of the large Au-As-Sb-Hg-Tl Vorontsovka deposit located within a volcanogenicsedimentary, substantially carbonate rock sequence. Closely spaced swarms of Devonian pre-ore and Carboniferous post-ore mafic dykes have been identified within the deposit. The primary geochemical halos of the Vorontsovka deposit have a multielement composition and, coupled with the ores, form a thick ore-halo zone confined to the gentle tectonic contact of sandstone-siltstone and limestone units. The main halo-forming elements are zonally distributed in the section. The footwall side of the gold deposit (rear zone) is dominated by Zn, Cd, Cu, Pb, Ag, and Bi; the axial zone, by Sb, Hg, Tl, and As; and the hanging side (frontal zone), by
 As, Zn, Hg, Pb, Ag, (Cu). In the east (closer to the Auerbakh granitoid massif), Ag, Zn, Pb, Mn, Y, Mo, and W relatively accumulate, while in the west (most remotely from the intrusive), Sb, Ba, As, Hg, Co, Ni, and Sn dominate. The 40Ar/39Ar age of ~391.1 million years, obtained for hydromica of the gold-arsenic ores, corresponds to the period of emplacement of granodiorite of the final Auerbakh massif intrusive phase. The conclusion is made on the crucial magmatic contribution to the formation of gold ores of the deposit.

The effect of load and binding position on the friction of cross-country skis

This study investigates the effect of moving the binding and adjusting the normal load on friction for a modern cross-country ski. The binding was moved 10 cm forward and backward from the normal position. The results showed that moving the binding backward on the ski reduced the friction at cold (−10 °C) and warm air temperatures (+5 °C). At intermediate temperatures (−2 °C), neither changes to the binding position nor the total load affected the friction coefficient. Measurement of pressure zone profiles revealed that moving the binding backward reduced the apparent contact area, increased the average contact pressure, increased the peak pressure in the rear zone and increased the spacing between the front and rear contact zones of the ski.

Research on Siro fancy yarn properties based on the novel drafting rubber roller

Due to the intimate relationship with the yarn’s properties, rubber rollers are an integral component of the drafting process. An innovative method for generating colored Siro yarns with regularly variable linear density is discussed in this article. To manufacture Siro yarns, the procedure includes altering the rubber rollers on a ring-spinning machine. By modifying the sorts of back-top rubber rollers and including roving slivers of different hues, this form of Siro yarns may be manufactured. These alterations to the shape of the rubber rollers produce exquisite yarn. Due to the employment of rubber rollers with dynamically varying diameters, a jaw with an imperfect engagement is formed. This leads to an incomplete draft, which forms a coarse knot with a continuous variance in yarn density along the yarn length direction. The Siro fancy yarns are spun using two distinct colors of roving slivers and drafting multiples. The objective of this study was to examine the impact of two rubber rollers of different diameters on the coarse knot cycles, the rear zone drafting multiplier, and the linear density of slub Siro colored yarns.

Geodynamic aspects of the metallogeny-magmatic zonality relationship of orogenic volcanic-plutonic belts

Research subject. The orogenic marginal-continental and collisional volcanic-plutonic belts, and the zonality of magmatism and metallogeny within them, as well as the relationship of endogenous metallogeny with magmatic zonality and geodynamics of belt formation.Materials and methods include the long-term studies of the Devonian and Upper-Paleozoic belts of Kazakhstan and the Cretaceous-Paleogenic belt of Sikhote-Alin; an analysis of the alterations in the material parameters of magmatites; the identification of the front and rear parts of the belts and the arrangement features of metallogenic zones within their limits; and the data on other belts of the world.Results. For the marginal continental belts, an asymmetric change of the tholeiitic and low-potassium magmatites of the calcareous-alkaline petrochemical series of the frontal zone of the belt into the magmatites of the high-potassium branch of the calcareous-alkaline and shoshonite series of the rear zone (Devonian and Upper Paleozoic belts of Kazakhstan) has been established. In the same direction, the elemental, as well as the genetic type of deposits changes: pyrite copper-polymetallic frontal zones are replaced by molybdenum-copper-porphyry rear zones (near the border with the frontal zone) and then by rare metal ones. This is also characteristic of the Andean and Okhotsk-Chukchi belts. The collision belts are characterised by symmetrical zonality with a change from rare metal deposits in the centre to copper-polymetallic deposits at the edges (Mongolia). In some cases (Sikhote-Alin and Japan), the continuity of the marginal-continental belt is disrupted as a result of the mantle diapir (or plume), symmetrical magmatic and metallogenic zonality occurs with the change of polymetallic manifestations (near the ocean–continent boundary) to rare-metal ones in the distance. Conclusions. The change in the material parameters of the magmatites of the marginal-continental belts correlates with the removal of their ranges from the ocean–continent transition zone to the interior of the latter. In this case, copper-polymetallic pyrite ore formations are replaced by copperporphyry and then by rare metal ones in this direction. This is due to subduction processes. The collision situation is characterised by a symmetrical zonality of material magmatic parameters with respect to the crowding zone and a symmetrical arrangement of metallogenic zones with a change of rare metal deposits in the crowding zone to copper and polymetallic along the frame. These data are important for metallogenic prediction, as well as for palaeotectonic reconstructions.

Reconstructing the Parameters of Internal Tidal Bores in the Banda Sea from Satellite Remote Sensing Data

This article presents an algorithm for estimating the vertical displacements of isopycn and horizontal current velocities caused by internal tidal borings from their manifestations in the roughness field on satellite images of the Banda Sea. The calculation algorithm is formulated within the framework of the Korteweg-de Vries equation (KdV), augmented with a term taking into account the cylindrical divergence. The coefficients of the KdV equation — quadratic nonlinearity, dispersion and tidal linear internal wave velocity — were calculated using the mean — climatic density profile in the Banda Sea. The leading soliton velocity and wavelength in the rear zone of the internal tidal borings were determined from satellite images. Using the proposed methodology, estimates of the maximum vertical displacement of the pycnocline/maximum amplitude of the leading soliton and the maximum velocity of surface currents induced by the internal tidal borings were obtained. It follows from the analysis of satellite images that the internal tidal borings in the Banda Sea are transformed under the action not only of nonlinearity and dispersion, but also of cylindrical divergence. It is shown in the framework of the knoidal model of internal tidal borings that in the process of evolution the energy of its leading and subsequent waves is attenuated due to the cylindrical divergence. This attenuation is estimated when the leading soliton travels a distance equal to twice the tidal period.

Discrete Element Simulation of Fracture Evolution around a Borehole for Gas Extraction in Coal Seams.

The stability analysis of underground caverns, tunnels, and boreholes is of great significance to underground engineering. In order to study the stress change of the coal around a hole and the evolution law of fractures during the coal seam drilling process, the discrete element simulation of the coal seam drilling process was carried out by using the particle flow code (PFC2D). The results show that during the drilling process, under the influence of confining pressure and drilling disturbance, the coal stress field around the hole and the development of fractures around the hole have the characteristics of zoning and dynamic evolution. In the axial direction of the borehole, it is divided into front and rear areas, and in the vertical axial direction, it is divided into the drilling disturbance zone and the confining pressure main control zone. During the drilling process, the direction of the maximum principal stress in the front zone gradually changes from the vertical hole axis to the direction parallel to the hole axis, and tension fractures are mainly developed along the drilling direction. In the rear zone, the principal stress direction tends to be stable and the principal stress value undergoes dynamic changes, and a large number of vertical hole axis tension fractures are developed. The drilling disturbance zone appears near the hole wall and has an important influence on the stability of the hole wall, while the confining pressure main control zone determines the antireflection effect around the hole and the influence radius of the hole. This work helps the understanding of the damage range and failure characteristics of the surrounding rock during the drilling process and has great significance for the guidance of drilling design.

Comparative study of unsteady flow mechanisms for swept and radially stacked rotors in a dual-stage counter-rotating compressor

Counter-rotating (CR) compressor is a potential configuration to increase the thrust-to-weight ratio of aero-engines. The present study numerically investigated a dual-stage CR compressor by solving unsteady Reynolds-averaged Naiver–Stokes equations. The unsteady flow mechanisms were analyzed and compared for swept and baseline (radially stacked) CR rotors. Both of these rotor configurations were numerically simulated for the entire design speed line. The unsteady flow field near the mid-span and blade tip characterized by tip leakage vortex (TLV) was analyzed in detail for both near peak efficiency (NPE) and near stall (NS) conditions. According to the results, blade loading of the second rotor (R2) was much higher than that of the first rotor (R1). Moreover, the blade loading was higher in the swept rotors in comparison with the baseline CR rotors. In both baseline and swept CR compressors, the potential effect of R2 on the static pressure distribution of R1 was more significant compared to the opposite effect. Under the NS condition, the potential effect was confined in the rear zone of R1 where the potential flow of R2 passed. Despite the obvious impact of wake-induced negative jet on the flow field of R2 blade passage, the static pressure of R2 blade exhibited no evident variation except at 90% spanwise position. Although the blade loading of the swept CR compressor was increased, the potential effect of R2 on R1 was considerably reduced due to growth of axial gap between R1 and R2. Since the blade sweep improved the flow field, the wake passing effect on R2 was more moderate compared to that of the baseline CR compressor. The perturbation velocity magnitude of the swept CR compressor was approximately half of that of the baseline CR compressor. The TLV of R2 was periodically disturbed, and therefore, low axial velocity patches were observed on the TLV trajectory of R2. In addition, the swept CR compressor exhibited smaller low axial velocity patches of TLV due to weaker aerodynamic interaction between R1 and R2.

A Study on Daylighting Performance of Split Louver with Simplified Parametric Control

A split louver consists of two sections with their slat angles to be adjusted separately for glare protection and redirection of sunlight, respectively. The upper section works in conjunction with the lower section to enhance daylight availability and uniformity throughout the year. The study aims to improve the daylighting performance of the split louver by applying a simplified parametric control, which predetermines the angle difference between adjacent slats in the upper section for a chosen solar altitude and then keeps this difference fixed during operation. The slats in the upper section can be changed parametrically using the Grasshopper to reflect daylight onto the ceiling and then illuminate the rear zone of a space. The lower section of the split louver can control the daylight in the front space area and may affect the amount of light in the back. The performance indicator in evaluating the proposed split louver design for the chosen typical days is the percentage coverage of the work plane area for the illuminance range of 150~750 lux, which was achieved up to 100% in some cases. The proposed split louver with the simplified parametric control has the potential to provide relatively consistent and distributed daylight coverage of the floor area and a glare-free environment.

Crab diversity as support for ecotourism activities in Pejarakan Mangrove Forest, Buleleng, Bali, Indonesia

Abstract. Ginantra IK, Muksin IK, Joni M. 2021. Crab diversity as support for ecotourism activities in Pejarakan Mangrove Forest, Buleleng, Bali, Indonesia. Biodiversitas 22: 4139-4145. This research aims to determine the diversity of crabs to support ecotourism activities in the coastal mangrove forest of Pejarakan Buleleng. Sampling of crabs was carried out using the square method, as many as 23 squares were spread over three mangrove zones, namely the front zone, the middle zone, and the rear zone. The number of individual crustacean species in each square plot was counted. Crab identification is based on morphological characters (shell color, claw shape, body-color, body size). Habitat use activities are observed directly. The diversity of crabs was calculated using the Shannon-Wiener diversity index. The results showed that in the coastal mangrove area of Pejarakan Buleleng, there were 11 species of crabs (9 species of crabs and 2 species of hermit crabs). Species diversity is in the medium category (index 2.25) and evenness index is high (E = 0.93, mangrove conditions are stable). The seaward mangrove zone shows a higher diversity of crab species than the middle zone and the rear zone. The species of crabs that are quite abundant in the three zonings are Uca vocans, Chiromanthes sp., and Coenobita sp. Characteristics of crabs, activities, habitat use in mangrove zoning are attractions for ecotourism activities.

State Transition Modeling in Ultimate Frisbee: Adaptation of a Promising Method for Performance Analysis in Invasion Sports.

Although the body of literature in sport science is growing rapidly, certain sports have yet to benefit from this increased interest by the scientific community. One such sport is Ultimate Frisbee, officially known as Ultimate. Thus, the goal of this study was to describe the nature of the sport by identifying differences between winning and losing teams in elite-level competition. To do so, a customized observational system and a state transition model were developed and applied to 14 games from the 2017 American Ultimate Disc League season. The results reveal that, on average, 262.2 passes were completed by a team per game and 5.5 passes per possession. More than two-thirds of these passes were played from the mid zone (39.4 ± 6.57%) and the rear zone (35.2 ± 5.09%), nearest the team’s own end zone. Winning and losing teams do not differ in these general patterns, but winning teams played significantly fewer backward passes from the front zone to the mid zone, nearest the opponent’s end zone than losing teams (mean difference of −4.73%, t(13) = −4.980, p < 0.001, d = −1.16). Furthermore, losing teams scored fewer points when they started on defense, called breakpoints (mean difference of −5.57, t(13) = −6.365, p < 0.001, d = 2.30), and committed significantly more turnovers per game (mean difference of 5.64, t(13) = 5.85, p < 0.001, d = −1.18). Overall, this study provides the first empirical description of Ultimate and identifies relevant performance indicators to discriminate between winning and losing teams. We hope this article sheds light on the unique, but so far overlooked sport of Ultimate, and offers performance analysts the basis for future studies using state transition modeling in Ultimate as well as other invasion sports.

ВУЛКАНИЗМ РАННЕЙ СТАДИИ ФОРМИРОВАНИЯ ОСТРОВА ИТУРУП (КУРИЛЬСКАЯ ОСТРОВНАЯ ДУГА)

The article presents new petrogeochemical data on the Middle Miocene-Pliocene volcanic rocks from central part of Iturup Island (Great Kurile Chain). It is shown that volcanism of the Middle Miocene-Early Pliocene age in the central part of the Iturup Island took place in a suprasubduction setting. The distribution of high field strength elements (HFSE) and their ratio in the basaltoids indicate their formation upon partial melting of the depleted upper mantle, while the enrichment of rocks with large ionic lithophilic elements (LILE) indicates both a fluid mantle additive introduced into the melts during the evolution of primary magma and the participation of a low-temperature suprasubduction fluid. The established differences in the composition of the basaltoids of the frontal and rear zones due to the limited number of analyzed samples are considered preliminary. Thus, basaltoids in the rear zone are distinguished by higher concentrations of Th, Pb, HFSE (Nb, Zr, Y, Hf), relative enrichment in LREE, pronounced negative Zr and Hf anomalies, and positive Eu.

Steady and Unsteady Asymmetric Flow Regions Past an Axisymmetric Body

The theoretical solution of the flowfield past an axisymmetric body flying at a high angle of attack at subsonic flow conditions is a challenging problem since it entails large areas of boundary-layer separation and a complex vortex sheet structure. At high angles of attack, the flow is asymmetric and shows a dependence on the orientation angle, provided the body surface has sufficient roughness. Regarding theoretical simulations based on the unsteady Reynolds-averaged Navier–Stokes equations, eddy-viscosity turbulence models fail to simulate the unsteady flow structure in the rear zone of the body, yielding sectional side forces far different from those measured in experiments. Solutions obtained in this work by using Reynolds stress turbulence models combined with scale-adaptive simulation past an ogive-cylinder configuration show their ability to reproduce the essential features of the unsteady flow in the rear body. The model appears to be a suitable tool to investigate the complexities of this type of flow.

Impact of radar data assimilation on simulations of precipitable water with the Harmonie model: A case study over Cyprus

Understanding the mesoscale spatial and temporal variability of precipitation (of the order of 1 to 100 km, and of minutes to hours, respectively) is essential for larger-scale studies, especially in highly heterogeneous areas, such as coastal regions, mountains and urban areas. The adequate capturing of the precipitation patterns in both diagnostic and prognostic terms remains an open challenge. On the one hand, commonly used ground measuring devices, such as rain gauges, disdrometers and other point instruments, exhibit an ineffective sampling for the whole range of scales and areas covered with precipitation. On the other hand, weather radars provide a much greater spatial and temporal resolution which, however, must be exploited with care in rain rate estimations, due to complicated and non-unique transfer functions used in the processing procedures. This study aims at bridging, to at least some extent, this scale gap and to demonstrate the role of fine-scale precipitation estimates derived from weather radar data, and to illustrate their impacts on larger scale weather patterns. The focus is on the precipitable water content and its changes during a Mediterranean cyclone evolution.In this paper, the first results with the regional radar signal processing chain that provides the radar data assimilation (RDA) in the Harmonie convection permitting numerical model are described. The numerical experiments exhibit effective simulation of the precipitable water at different stages of the frontal depression which affected Cyprus in the Eastern Mediterranean, during 31 December 2018–2 January 2019. In particular, it was found that the major volume of precipitable water was related to the cyclone frontal zone (which is in turn related to heavier precipitation), followed by a weaker field of precipitable water behind the frontal zone (and weaker precipitation). During the whole severe weather period, the precipitable water minimum was maintained over the island's central mountain range, reflecting the importance of interactions and feedbacks between the air flow and orography.The radar data assimilation influences the results of the simulations, depending on the particular area and cyclone stage. The largest innovations due to RDA occur with the approach of the cyclone's frontal zone. Enhancement of precipitable water due to RDA is observed over most of the whole area, but this is more pronounced in weaker precipitation locations. The impact is associated with a shift of the precipitable water maximum towards higher values in the precipitable water distribution, which is accompanied by enlarged sizes of areas with greater precipitable water. During the cyclone's mature stage and at the rear zone, the integrated RDA impact over the whole domain is almost negligible but takes the form of mesoscale cells of opposite signs; at this stage, radar measurements yield an alteration of both the positions and rates of spatial precipitable water fields, which result in intermittent mesoscale changes.

Experimental evaluation of cooling characteristic, airflow distribution and mass transfer in a cold store

AbstractThe cooling characteristics and safety of food products inside the cold room depend on the temperature field and govern by the airflow distribution. The nonuniform air distribution creates variability in the cooling rate and transpiration rate. The volume of products in cold‐store influences the airflow pattern and, therefore, experimental study performed on loaded cold‐room. The experiment includes measuring and estimating temperature, convective heat transfer coefficient, and weight loss to evaluate the heat and mass transfer. The airflow behavior inside the cold room is observed highly nonuniform. In the product‐zone, cooling‐air flow with higher velocities near the floor and flow uniformity decrease with the height of the cold store. The product cooling variability observed along the path of the flow as the product in front zone cooled at a rapid rate compared to that placed in the rear zone. The estimated average transpiration rate ranged from 0.033 to 0.16 gkg−1 h−1 in front zone and in rear zone; it is ranged from 0.038 to 0.2 gkg−1 h−1. The experimental study of loaded cold store presents the factual nature of cooling and storage condition, and the zone‐wise examination of operating variable beneficial for understanding the cooling characteristics included heat and mass transfer.Practical ApplicationsThe room air cooling method is the most accepted method to preserve food products, and the preservation (operating) condition of the cold room influences the heat and mass (product weight) transfer phenomenon. The experimental observation of operating conditions (airflow field, temperature change, air relative humidity, convective heat transfer coefficient) is performed at multiple locations and explained. The nonuniformity in operating conditions is observed, which leads the variability in heat and mass transfer process. The theoretical estimation of mass transfer is evaluated and validated with the experimental data. This work is used to provide better insight into the zone‐wise distribution of preservation conditions and its influences on the food product.

On the effects of the free-stream turbulence on the heat transfer from a sphere

Free-stream turbulence is present in many engineering applications and is known to affect both bluff body aerodynamics and heat transfer. In this work, its effects on the heat transfer and the near wake behind a sphere are studied. To do this, direct and large-eddy simulations of the flow at the moderate Reynolds numbers of Re=1000 and Re=104,with levels of incoming turbulence up to 10% and a length scale of O(D),D being the sphere diameter, are performed. At the Reynolds numbers under consideration, significant changes are observed. Incoming turbulence delays the separation of the laminar boundary layer from the sphere, while at the same time the drag coefficient and the Nusselt number are increased. The incoming level of turbulence also increases the momentum transfer from the surrounding fluid and energises the separated shear-layer. As a consequence, there is a shrinking of the recirculation zone which intensifies the heat transfer from the sphere and thus, the Nusselt number and its fluctuations, especially in the rear zone of the sphere. It is shown that free-stream turbulence increases the turbulent heat flux in the wake, with a larger entrainment of colder fluid from the surroundings, thus producing a faster decay of the temperature at larger levels of turbulence intensity.

Rear zone for energy efficiency in large mosques in Saudi Arabia

Mosques are places of worship for Muslims and have great importance, unique function and peculiar operating characteristics. Large mosques in Saudi cities are those in which Friday prayers (the noon prayer on Friday) are performed. Therefore, they are designed to accommodate a large number of worshippers at one time. However, only 15% of the full capacity is present at each of the remaining five-daily prayers. For approximately an hour, the Heating, Ventilation and Air-Conditioning (HVAC) and lighting systems are on in the entire mosque during each of these five daily times. Maintaining indoor thermal comfort in Saudi Arabian hot areas requires a considerable amount of energy for cooling. Hence, to alleviate this dilemma, a rear zone idea is proposed in this study. Fieldwork and simulation methods were used to predict the reduction in energy consumption and the payback of the incurred costs. Results show a reduction in annual energy consumption of approximately 64%, which is equivalent to USD 8203. The cost of the partition can be paid back in 18.2 months.

Pattern Zone Ecosystem of Mangrove in Juanga Village, Morotai Island District

ABSTRACTMangroves are one of the most important natural resources in coastal areas. Availability of various types of food that are on ecosystems is already making its presence as a local nursery, where searching for eating and also serve as a regional tourist ecosystem of mangrove. In use as Regional tourist mangrove need to attention the condition of the physical environment and the distribution pattern of zoning. Research is carried out in the month October to November 2019 in the village of Juanga Regency island of Morotai. Data zoning mangrove using the method of the combination is to combine the methods of plots to track transects, to determine the four stations of observation of each respective stations and each station is divided into three zones: zone front, zone of middle and zone back starting from the point of the outermost growth of types of mangrove constituent primary to the point of transition between sea and land. The research results of the study found 5 types of mangroves namely Rhizophora mucronata, Ceriops decandra, Rhizophora apiculata, Xylocarpus granatum and Sonneratia alba. The distribution of zoning patterns in the front zones of station I and the middle zone is dominated by Rhizophora mucronata and Rhizophora apiculata types, the rear zone is dominated by Ceriops decandra. Station II front zone is dominated by Sonneratia alba, middle zone (Rhizophora mucronata), rear zone (Ceriops decandra). At station III the front zone (Rhizophora apiculata), the middle zone and the rear zone (Ceriops decandra) while at station IV the front zone, the middle zone and the rear zone are dominated by the Ceriops decandra type.

Pemilihan Parameter Utama Pengacuan Suntikan dalam Pemprosesan Polimer: Ulasan Ilmiah

An injection system is a heart of an Injection Moulding process and it includes a variety of factors that need to be coordinated and adjusted. This control system covers parameter that are classified as four main parameters: pressure, temperature, time, and distance. Injection Pressure is the pressure needed to move melted polymer material into the mould. Holding Pressure is the phase which come after the injection pressure stage. Barrel Temperature which can be divided into four operated temperature zones in the injection unit consisted of the rear zone, the middle zone, the front zone, and the nozzle zone. Mould Temperature is typically used for cooling the polymer material once it is injected into a mould that has a cooling water channel. A total of 40 research papers have been studied and summarized based on their related parameters that has been used in the analysis. Most researchers includes the Taguchi method in their research methodology. From the analysis, there are four frequently used parameters which are Barrel Temperature, Mould Temperature. Injection Pressure and Holding Pressure in order to produce a product, to improve product with better quality or products with maximum strength. This paper is a review of all the main processing parameters that are involves in plastic injection molding process.

On petrogeochemical zoning of mesozoic volcanites of the ore fields of gold and polymetallic deposits of the Eastern Transbaikalia

Transverse petrogeochemical zoning in the location of volcanites of Shadaronsky (J2-3) and Mulinsky (J2-3) series, characteristic of volcanic arcs, has been revealed in the Eastern Transbaikalia. Volcanites of the tholeiitic and calc-alkaline series are developed in the frontal zone of the volcanic arc, in the suture zone of the Mongolo-Okhotsk suture (MOS), in the rear zone of the MOS - volcanites of the calc-alkaline series. The volcanites of the frontal and rear parts differ in their petrogeochemical composition, in the degree of oxidation of iron and in the distribution of rare earth elements (REE). These differences are characteristic of the volcanic arcs of the transition zones from the ocean to the continent. Vulcano-plutonic structures of the frontal zone of MOS produce gold mineralization, the rear zone of MOS - polymetallic mineralization.

Petrogeochemical Zoning of Mesozoic Volcanic Rocks of the Ore Fields of Gold and Polymetallic Deposits of Eastern Transbaikalia

Transverse petrogeochemical zoning in the location of volcanites of Shadaronsky (J 2-3 ) and Mulinsky (J 2-3 ) series, characteristic of volcanic arcs, has been revealed in the Eastern Transbaikalia. Volcanites of the tholeiitic and calc-alkaline series are developed in the frontal zone of the volcanic arc, in the suture zone of the Mongolo-Okhotsk suture (MOS), in the rear zone of the MOS - volcanites of the calc-alkaline series. The volcanites of the frontal and rear parts differ in their petrogeochemical composition, in the degree of oxidation of iron and in the distribution of rare earth elements (REE). These differences are characteristic of the volcanic arcs of the transition zones from the ocean to the continent. Vulcano-plutonic structures of the frontal zone of MOS produce gold mineralization, the rear zone of MOS - polymetallic mineralization.