Great Belt Research Articles

A method for risk analysis of ship collisions with stationary infrastructure using AIS data and a ship manoeuvring simulator

The study presents a methodology that uses AIS data and a ship manoeuvring simulator to simulate and analyse marine traffic schemes with regard to risks for accidents. An event identification method is presented, which is needed for the accident scenario part of the methodology. This is based on AIS data, where the Great Belt VTS area was used to verify the methodology. Three events that could result in ship-bridge allisions were modelled and simulated in the simulator: drifting ship, sharp turning ship and miss of turning point. The Monte Carlo method was used to perform large number of simulator runs, including a parameter sensitivity analysis. The probability of a ship allision against the Great Belt Bridge was calculated to be 0.007. Analysis of the ship-bridge allision cases was shown to be dominated by the event drifting ship. This event has a relatively low kinetic energy at the impact, and the expected allision energy for a 1,000-year allision corresponds to a 178 m tanker with 57,870 DWT and ship speed 14.6 knots. Finally, this study presents a mitigation analysis, which shows how the probability of allisions can be reduced by reducing the ship speed or altering the traffic separation scheme.

Spatio-Temporal Changing Scenario of Growth and Structure of Manufacturing Industries in Asansol-Durgapur Region, West Bengal

Asansol-Durgapur Industrial Region serves as nerve-knot of the economy of West Bengal as well as the entire economic region of Eastern India because of its enormous reservoir of excellent quality of coal of Raniganj Coalfield, outstanding network of transport by rail and road, skillful and cheap labour in close proximity of states. With the establishment of a number of large industrial units like Iron & Steel Plant, Durgapur Steel Plant, Chittaranjan Locomotive works, Durgapur Alloy Steel Plant, Durgapur Thermal Power Station, and hundreds of medium and small-scale industries have made the region great industrial belt after Hooghly industrial belt in West Bengal. Though there was rapid industrialization after independence period but the growth of industries has not taken place uniformly throughout the study area. This is because, high manufacturing intensity found in Durgapur, Asansol, Raniganj and Kulti areas whereas the Salanpur, Jamuria, Fraidpur, Barabani areas witnesses low manufacturing intensity. The decadal growth of industries also noteworthy, in 1951 there were 46 industrial units and it increased to 430 in 2019. The number of basic metal and engineering units was 2 and 18 respectively in the year 1951 whereas in 2019 the basic metal and engineering unit increased to 122 and 66 respectively. This paper primarily focuses on the estimation of spatial and temporal distribution of manufacturing industrial units, growth and structural changes, manufacturing intensity and concentration of the manufacturing sector during the period of 1951 to 2019 in Asansol-Durgapur Industrial Region.

“Crossing the River by Feeling the Stones”: How Borders, Energy Development and Ongoing Experimentation Shape the Dynamic Transformation of Yunnan Province

ABSTRACT This article details the dynamic transformation of Yunnan’s border regime during the early twenty-first century through the Great Western Development Strategy, Bridgehead and Belt and Road Initiative. Although China’s macro-scale national strategies frame border change, experimental ideology and local-scale mechanisms drive border change and refine through constant adjustment. As illustrated in this article, border positioning and repositioning is incremental, constituted of many small and different components, dependent on locals and localities, and employing an array of border mediation strategies. Seemingly large scale border alteration is actually accrued through micro-changes, small scale experiments in specific places, trial and error adjustments and, essentially “crossing the river by feeling the stones.” Whereas Yunnan’s geostrategic location and vast energy resources have catapulted the province through rapid growth and into a globalized international context, ongoing transformation has also bolstered boundaries and bordering processes in Yunnan’s mobile border regime and generated antithetical and reactionary bordering responses that need to be viewed within a post-globalization border framework.

Testing the climate intervention potential of ocean afforestation using the Great Atlantic Sargassum Belt

Ensuring that global warming remains <2 °C requires rapid CO2 emissions reduction. Additionally, 100–900 gigatons CO2 must be removed from the atmosphere by 2100 using a portfolio of CO2 removal (CDR) methods. Ocean afforestation, CDR through basin-scale seaweed farming in the open ocean, is seen as a key component of the marine portfolio. Here, we analyse the CDR potential of recent re-occurring trans-basin belts of the floating seaweed Sargassum in the (sub)tropical North Atlantic as a natural analogue for ocean afforestation. We show that two biogeochemical feedbacks, nutrient reallocation and calcification by encrusting marine life, reduce the CDR efficacy of Sargassum by 20–100%. Atmospheric CO2 influx into the surface seawater, after CO2-fixation by Sargassum, takes 2.5–18 times longer than the CO2-deficient seawater remains in contact with the atmosphere, potentially hindering CDR verification. Furthermore, we estimate that increased ocean albedo, due to floating Sargassum, could influence climate radiative forcing more than Sargassum-CDR. Our analysis shows that multifaceted Earth-system feedbacks determine the efficacy of ocean afforestation.

When were the straits between the Baltic Sea and the Kattegat inundated by the sea during the Holocene?

The timing of the flooding of the Danish/German/Swedish straits and the first marine influence in the Baltic Basin after the Ancylus Lake stage has been much debated. Here we present 47 new radiocarbon ages from sediment cores retrieved from Danish waters, ages that record the marine transgression of the area. Most of the ages are based on shells of marine molluscs, hence the ages are uncertain because we do not know the precise reservoir age in the past. We use a reservoir age of 400 years, which is based on dating of museum specimens collected live before testing of nuclear bombs. It appears from the ages that the Great Belt (Storebælt) was inundated before The Sound (Øresund). The oldest ages on marine shells from the northern part of the Great Belt region are about 8.9 cal. ka BP. From the central part of the Great Belt, the oldest ages are about 8.2 cal. ka BP, in Mecklenburg Bay 8.1 cal. ka BP and in the Arkona Basin 7.1 cal. ka BP. Sediments deposited prior to the occurrence of marine molluscs contain brackish‐water ostracods (Cyprideis torosa and Cytheromorpha fuscata); the sediments are usually laminated and non‐bioturbated mud. The brackish‐water phase may have lasted 500–1000 years. The youngest lake deposits without signs of marine influence are dated to c. 8.8 cal. ka BP (central Great Belt), 8.7 cal. ka BP (Little Belt) and 8.5 cal. ka BP (Arkona Basin). We see no evidence for marine influence at c. 10 cal. ka BP as recorded by some studies from the Baltic Basin.

The White-headed yellow wagtail &lt;em&gt;Motacilla flava leucocephala&lt;/em&gt; (Przewalski, 1887): migration, movements, and breeding and wintering ranges

The subspecies leucocephala of the western yellow wagtail Motacilla flava is endemic to the Altai-Sayan Ecoregion (Central Asia). The occurrence of leucocephala is associated with saline water bodies and solonchak habitats. Its distribution, especially outside the breeding season, is still uncertain. The aim of this work is to better define the breeding range, migratory movements, and the wintering range of this subspecies and provide guidance to distinguish whiteheaded intraspecific hybrids from the true leucocephala subspecies. The reproductive range of leucocephala is concentrated near lakes and wetlands in the Great Lakes Depression (north-west Mongolia) and in the flat southern part of the Tuva Republic (Russian Federation). The small population uses two separate areas for wintering: the eastern equatorial Africa reached through the Great Rift Valley Flyway and the Indian subcontinent reached along a route that bypasses the great belt of mountains and plateaus of central Asia to the west.

A New Reconstruction for Permian East Gondwana Based on Zircon Data From Ophiolite of the East Australian Great Serpentinite Belt

AbstractThe Great Serpentinite Belt of eastern Australia is a ∼1500 km long dismembered ophiolite assumed to be Cambrian based on studies of small (typically &lt;50 m2) exotic meta‐igneous inclusions despite contrasting ages (Cambrian—Devonian) and complex P‐T histories. To overcome these issues, we studied a ∼18 km2 coherent block of dismembered ophiolite that provides robust geological context to sampling the ophiolite. Zircon U‐Pb‐Hf‐O isotope and trace analyses from three plagiogranite dykes cutting massive gabbro confirm ∼283–277 Ma ages and a mantle source. As a result, we argue older Cambrian to Devonian plagiogranite and subducted blocks were inherited from previous subduction events in eastern Australia. These findings allow us to match the Great Serpentinite Belt with the contemporary Dun Mountain ophiolite (New Zealand) and the Koh ophiolite (New Caledonia), thus supporting a new, integrated Pacific Gondwana margin paleogeography involving multiple arcs and subduction zones.

Utility analysis for SHM durations and service life extension of welds on steel bridge deck

Optimization of the duration of Structural Health Monitoring (SHM) campaigns is rarely performed. This article provides a utility-based solution to posteriorly determine: i) optimal monitoring durations and ii) the extension of the service life of the welds on a steel bridge deck. The approach is illustrated with a case study focusing on remaining fatigue life estimation of the welds on the orthotropic steel deck of the Great Belt Bridge, in Denmark. The identification of the optimal monitoring duration and the decision about extending the service life of the welds are modelled by maximizing the expected benefits and minimizing the structural risks. The results are a parametric analysis, mainly on the effect of the target probability, benefit, cost of failure, cost of rehabilitation, cost of monitoring and discount rate on the posterior utilities of monitoring strategies and the choice of service life considering the risk variability and the costs and benefits models. The results show that the decision on short-term monitoring, i.e., 1 week every six months, is overall the most valued SHM strategy. In addition, it is found that the target probability is the most sensitive parameter affecting the optimal SHM durations and service life extension of the welds.

Investigation of the performance of asphalt binder modified by sargassum

Permanent deformations (rutting) are the most frequent problem throughout the world in the design of heavy- traffic pavement roads, which is a consequence of the accumulation of small amounts of plastic deformations occurring whenever a load is applied on the asphalt. This problem arises when the asphalt binders are prepared from hot asphalt mixtures. For this reason, asphalt modifiers are used to minimize failures, avoiding both permanent deformations and the subsequent cracks appearing on the pavements. In this study, seaweed Sargassum (SGZ) was used for the first time as a modifier of asphalt binders, as a response to the urgent need of finding a way to handle and take advantage of the massive amounts of this biomass, which has been found in recent years on the beach coasts of the equatorial Atlantic Ocean forming what the authors call the Great Atlantic Sargassum Belt. The rheological properties of these asphalt binders were evaluated by means of a DSR (dynamic shear rheometer) equipment; the results showed that the addition of sargassum at different concentrations (0.5–4% wt) increased the permanent deformation factor (G*/sinδ), and that higher elastic behavior is reached on the 2.5% SGZ sample. Additionally, the thermal resistance towards high temperatures was identified and compared with the control sample, observing the best results on the SGZ 2.5% sample. This behavior was confirmed by the calculation of the penetration index (PI). Moreover, the thermal stability test was efficient for demonstrating an improvement of the compatibility between the sargassum and the asphalt caused by a reduction in the difference between their densities.

An American Disgrace

An American Disgrace

A Numerical Technique for Determining Aerodynamic Derivatives of a Suspension Bridge Deck

A novel two-dimensional numerical solution methodology based on variable wind angle of attack for numerical simulation of fluid-structure interaction associated with rotations of bridge deck section is proposed. In this methodology, the deck is considered fixed in the computational domain, while incremental inclination of flow approach and wind angle attack are applied to far-field boundaries of the initial mesh. The numerical simulation is carried out to calculate aerodynamic flutter derivatives of Great Belt East Bridge deck using commercial computational fluid dynamic code of ANSYS FLUENT combined with a developed MATLAB code for post-processing of the aerodynamic derivatives. The utilized finite volume flow solver is applied for two-dimensional flow simulation around structural sections. Aerodynamic flutter parameters of a thin flat plate and bridge deck are determined based on the proposed methodology. Comparison between the analysis results with simulated values and the measurements of wind tunnel tests or the Theodorsen’s solution shows that the accuracy of the present modeling strategy in prediction of the aerodynamic derivatives is promising.

Improvement of soil property mapping in the Great Clay Belt of northern Ontario using multi-source remotely sensed data

This study aimed to improve the accuracy in modelling the properties of forest soil by employing a variety of remotely sensed data. In addition to the commonly used multispectral satellite imagery, airborne LiDAR (light detection and ranging) data were exploited to derive detailed vegetation properties and topographic variables. Random forest (RF) and support vector machine (SVM) approaches were applied to classify soil types in terms of texture, calcareous substrate reaction to hydrochloric acid, and ELC (Ecological Land Classification) moisture regime. The developed methods were tested on data acquired over a boreal region (49° - 50° N, 81° - 84° W) with a combined area of 4,085 km2 in the Great Clay Belt (GCB) region, Ontario, Canada. Compared with the field-collected data, the overall accuracies and kappa coefficients of the retrieved soil properties were greater than 0.7 and 0.5, respectively. The accuracies attained between the RF and SVM approaches were similar, but in general the highest accuracies were achieved by the RF method. The models developed for the whole GCB regions generated accuracies comparable to those for the three sub-regions. The lowest modelling uncertainties occurred in areas dominated by peatland, whereas the highest modelling uncertainties existed in the regions with dry moisture regime or clayey soil at the surface. The results also showed that environmental covariates corresponding to vegetation were most important in the prediction of soil properties. Specifically, canopy height model (CHM) and gap fraction derived from LiDAR data, were among the most important variables.The inclusion of LiDAR-derived covariates demonstrated potential, applied in addition with topographic and climatic covariates and optical imagery. CHM pertains to the vertical dimension, and gap fraction relates to the density of the canopy layer, respectively; both covariates that offer supplemental detail that is not necessarily ascertained for the canopy by optical imagery.

Effects of Wind-Barrier Layout and Wind Turbulence on Aerodynamic Stability of Cable-Supported Bridges

Wind barriers are nowadays commonly placed on bridges to protect vehicles from adverse cross-wind effects. In addition to this beneficial influence, wind barriers may adversely affect the bridge dynamic stability. This is particularly exhibited for long-span cable-supported bridges. It is therefore the scope of the present study to analyze the effects of wind barriers on aerodynamic and aeroelastic characteristics of bridge-deck sections of long-span cable-supported bridges together with the respective flow characteristics around bridge-deck sections. The focus is on various arrangements of wind barriers, i.e., (1) wind barriers placed at the windward bridge-deck edge only; (2) wind barriers placed at the leeward bridge-deck edge only; and (3) wind barriers placed at both windward and leeward bridge-deck edges. This was carried out experimentally on small-scale models in a boundary layer wind tunnel. Three typical bridge-deck section models were studied, i.e., Great Belt (Denmark), Kao-Pin Hsi (Taiwan), and Golden Gate (United States). The galloping susceptibility of the bridge-deck sections in all arrangements of wind barriers proved to be the same, as is the case for the empty bridge-deck sections without wind barriers; i.e., from this point of view, wind barriers do not adversely bridge dynamic stability. However, in configurations with the windward wind barrier only, as well as both windward and leeward wind barriers, the flutter susceptibility of the bridge-deck sections increases substantially; i.e., the critical flow velocity for the bridge flutter decreased significantly in comparison with the respective empty bridge-deck sections. For the leeward wind barrier only, the flutter susceptibility of the bridge-deck sections did not change and remained the same as it was for the empty bridge-deck sections. The empty bridge-deck sections do not exhibit any significant change concerning their susceptibility to flutter for various turbulence levels of the incoming freestream flow. The flutter susceptibility of cable-supported bridges equipped with wind barriers is lower in more turbulent incoming flows. The bridge decks with wind barriers are more resilient to flutter in more turbulent winds. Shear layers that separate from the top of the wind barrier may have an important role in the self-excited lift force and the pitch moment and, consequently, the dynamic behavior of bridge decks.

Mining and Environmental Rights in Zimbabwe. A Case of Zvishavane District

This paper examines the impact of artisanal small-scale mining on the environmental rights of communities in Zvishavane, Zimbabwe. All over the world, mining has been significant in enhancing the livelihoods of the people by reducing poverty and ensuring food security. Despite its major contribution to economic growth and development, mining is responsible for environmental degradation. The environmental rights of many indigenous communities in Zimbabwe are violated by small-scale mining operations. Zvishavane is one of the marginalized communities in Zimbabwe where all types of mining activities are taking place as the district is located along the Great Dyke mineral belt. The dominant mining entities in the district are artisanal small-scale miners exploiting gold and chrome. Given the low capitalization that characterizes artisanal small-scale miners, the degree to which these entities comply with the country's legislation on environmental protection becomes very doubtful. The study was conducted through interviews and focus group discussions with key informants in the Mapanzure community in Zvishavane. The findings of this study highlight that artisanal small-scale chrome and gold miners are largely responsible for the contamination of water sources, land degradation, excessive air pollution and deforestation, which exposes mining communities in Zvishavane to health hazards such as cholera, bilharzia, asthma and cirrhosis. Findings of this study provide valuable insights for policymakers and practitioners on sustainable mining in marginalized communities. Keywords: Mining, Environmental rights, Artisanal small-scale miners and Zvishavane District DOI: 10.7176/DCS/10-8-06 Publication date: August 31 st 2020

ЭЛЕМЕНТЫ КОНСКОГО СНАРЯЖЕНИЯ ПОСТ-ГУННСКОГО ВРЕМЕНИ НА СЕВЕРНОМ КАВКАЗЕ И ИХ ПАРАЛЛЕЛИ НА ОКРАИНАХ СТЕПИ

On the archaeological sites of the North Caucasus for the post-Hunnic Period (the so-called horizon of Shupovo, mid-V – mid-VI centuries AD), a number of indicative elements of horse equipment — bits, buckles, strap appliques, and metal appliques for saddles — were revealed. The same things are recorded in settled barbarians on the boundary of the nomadic steppe. Moreover, with the exception of saddle appliques, they are absent in the burials of the steppe nomads of the same time (Huns, Bulgarians, Ugrians). Nevertheless, it seems that the distribution of horse equipment is evidence of the spread of a kind of "military" fashion, primarily in the "leader" environment of sedentary barbarians, culturally, and maybe politically oriented to the nomadic steppe. The latter circumstance can explain the distribution of the things examined here primarily in the borderlands of the Great Steppe Belt. We can talk about barbarians who were in allied (or subordinate-allied) relations with the steppe nomads.&#x0D;

ПЕРЕДУМОВИ ТА ПЕРСПЕКТИВИ ІННОВАЦІЙНО-ІНВЕСТИЦІЙНОГО СПІВРОБІТНИЦТВА УКРАЇНИ ТА КИТАЮ

In the article, the author considers China's position as an initiator and investor of large-scale infrastructure projects and examines its position in the world innovation ratings of countries. In particular, the most large-scale infrastructure project of China in the framework of international cooperation for the development of the great silk road economic belt, which involves the formation of a common space for China and neighboring countries for their stable development, was considered. Examples of implementation of infrastructure projects in Ukraine and the effectiveness of their practical implementation are analyzed. The dynamics of direct investment concentrated in the economy of Ukraine, including China, is considered. It is concluded that despite the dominance of the global trend of slowing economic development, the innovative activity of the world's countries is also gaining momentum, which is expressed in particular in an increase in investment aimed at research and development. We have studied the pace of development and financing of innovation activities in Ukraine, including through budget financing. It is established that now China's economic policy is focused on enhancing the country's innovative development and implementing structural changes. Measures of state support in this direction should be defined as: reducing tax pressure on innovation-oriented companies; providing financial support to real economy entities; creating a favorable environment for research and development; improving legislation in the field of intellectual property protection, and so on. Comprehensive support for the development of scientific and technical clusters of the country allows us to occupy leading positions in the world. The successful experience of China in financing research and development and the dynamics of their investment in recent years are analyzed. A comparative analysis of the innovation and investment opportunities of Ukraine and China was conducted, which allowed us to conclude that there is a significant gap in the level of their innovation and investment growth and the feasibility of cooperation between the countries in the direction of leveling their territorial development. The strategic significance of implementing joint projects of innovation and investment growth in Ukraine and China is substantiated.

Reliability based design optimization for bridge girder shape and plate thicknesses of long-span suspension bridges considering aeroelastic constraint

Reliability based design optimization (RBDO) for deck shape and thicknesses of the steel plates that form a box girder of long-span suspension bridges is performed considering probabilistic flutter constraint. The entire process was carried out fully computationally including the definition of flutter derivatives. Surrogate models were constructed to estimate the aerodynamic response of the bridge for different deck shapes based on the results from a series of CFD simulations. Some of the aerodynamic coefficients were validated by wind tunnel tests. Flutter derivatives were then estimated using quasi-steady approach for the evaluation of critical flutter velocity. Uncertainty in the aerodynamic coefficients from CFD simulations as well as the extreme wind speed at the bridge site were considered. The formulated methodology was applied to the Great Belt East Bridge.

The Genesis of the Giant Shuangjianzishan Epithermal Ag-Pb-Zn Deposit, Inner Mongolia, Northeastern China

Abstract The newly discovered Shuangjianzishan Ag-Pb-Zn deposit, with 145 Mt of ore grading 128.5 g/t Ag (locally up to 32,000 g/t) and 2.2 wt % Pb + Zn, is located in the Great Hinggan Range metallogenic belt, northeastern China, and is currently the largest Ag deposit in Asia. The Ag-Pb-Zn orebodies occur as veins and are hosted primarily by a Permian slate. Recent drilling and core logging have identified a partially Mo mineralized granite porphyry intrusion adjacent to the Ag-Pb-Zn mineralized veins. This well-preserved magmatic-hydrothermal system therefore offers an excellent opportunity to evaluate the possible temporal and genetic relationship between Mo-mineralized porphyry intrusions and Ag-Pb-Zn veins. Three primary paragenetic stages of veining have been recognized: (I) early pyrite + quartz ± K-feldspar, (II) main ore sulfide + sulfosalt + quartz + calcite + sericite + chlorite ± epidote, and (III) post-ore quartz. The silver mineralization occurs mainly in the late paragenetic part of Stage II, in which canfieldite (Ag8SnS6), argentite (Ag2S) and freibergite [(Ag, Cu)12Sb4S13] are the dominant Ag-bearing ore minerals. A combination of ore mineral chemical and sulfur isotope geothermometers and physicochemical calculations suggest that the Ag-Pb-Zn mineralization took place at a temperature of 250° to 200°C, a pH of 6.7 to 5.6, and a Δlogfo2 (HM) of –2.4 to –8.7. A conspicuous enrichment of Sn and Se in the ore, which is represented by minerals containing the metal suite Ag-Pb-Zn-(Cu-Sn-Se-Sb), likely reflects a close genetic association between the base metal mineralization and a magma. In situ analyses show that the δ34S values of the sulfides and Ag-bearing sulfosalts from the Ag-Pb-Zn mineralized veins vary from –4.67 to +2.44‰; the mean value is –2.11 ± 1.49‰ (n = 77). The calculated mean δ34SH2S value of the ore-forming fluid is –1.65 ± 0.83‰, which is indicative of a magmatic sulfur source. In situ Pb isotope analyses of the ore minerals yielded a narrow range of values (206Pb/204Pb of 18.243–18.310, 207Pb/204Pb of 15.503–15.563 and 208Pb/204Pb of 38.053–38.203, n = 59). Comparisons to corresponding isotopic data for the various rock units in the area and sulfides from nearby ore deposits indicate that there were substantial contributions of Pb and other metals (e.g., Ag and Zn) to the Shuangjianzishan deposit from a Mesozoic granitic source. Diorite-granodiorite dikes and dacite are crosscut by the Ag-Pb-Zn veins, and therefore, predate ore formation. These rock units have zircon U-Pb ages of 250.2 ± 2.0 and 133.9 ± 1.4 Ma, respectively. A concealed, weakly Mo mineralized granite porphyry intrusion proximal to the Ag-Pb-Zn mineralized vein system yielded zircon U-Pb ages of 134.4 ± 1.0 (MSWD = 0.1) and 134.4 ± 1.0 Ma (MSWD = 0.2), for coarse- and fine-grained facies, respectively. These ages are indistinguishable within the uncertainty from the zircon ages for the dacite and a granite intrusion ~2 km north of the mineralized veins, which has a weighted mean zircon U-Pb age of 135.2 ± 1.4 Ma (MSWD = 0.78). Molybdenite from three quartz vein/veinlet samples hosted by slate immediately above the porphyry intrusion yielded Re-Os model ages from 136.3 ± 0.9 to 133.7 ± 1.2 Ma and a weighted mean Re-Os age of 134.9 ± 3.4 Ma. Finally, three pyrite samples separated from the Ag-Pb-Zn mineralized veins have a weighted mean Re-Os model age of 135.0 ± 0.6 Ma. The very similar zircon U-Pb ages for the Mo-mineralized granite porphyry and dacite, and Re-Os ages for molybdenite and pyrite in the Shuangjianzishan ore district indicate that the Mesozoic magmatic-hydrothermal activity was restricted to a relatively short time interval (~136–133 Ma). They also suggest that the weakly Mo mineralized granite porphyry was likely the source of the fluids and metals that produced the Ag-Pb-Zn mineralization. Based on our geological observations and an extensive analytical database, a model is proposed for the genesis of the giant Shuangjianzishan Ag-Pb-Zn deposit in which the ore-forming fluid and its metals (i.e., Ag, Pb, and Zn) were exsolved during crystallization of the final phase of a composite granite porphyry intrusion. This fluid transported metals to the distal parts of the system, where they were deposited in preexisting faults or fractures created by the withdrawal of magma during the waning stages of the magmatic-hydrothermal event. The present study of the Shuangjianzishan Ag-Pb-Zn deposit and those of other magmatic-hydrothermal ore deposits in the region provide compelling evidence that the widespread Mesozoic felsic magmatism and Ag-Pb-Zn mineralization in the southern Great Hinggan Range took place in an intracontinental extensional tectonic setting, which was synchronous with, and spatially associated to, Paleo-Pacific slab rollback and lithospheric delamination and thinning.

Оғыз таңбалары

The Oghuz, whose history of emergence and development lies in the period of the VIII–XIII centuries, played a significant role in the formation of modern Turkic peoples. The Oghuz tribes consisted of 24 families. They started the process of Turkization of the peoples of the medieval Eurasian steppes. The evidence of it is the similarity of Oghuz tamgas found on the territory of Zhetysu, Syr Darya and Western Kazakhstan with tamgas of other Turkic-speaking peoples. Today Oghuz tamgas attract the attention of many domestic and foreign researchers, but scientists are only interested in genealogical and cultural aspects so far. In case tamgas are perceived as a full-fledged source, some problems related to the studies of the medieval history of the Great belt of steppes can be solved, for example, such as clarifying the geography of distribution of the Oghuz tribes, analyzing their political and economic activity, as well as determining the degree of kinship of the Turkic peoples among themselves. The article considers the pronounced differences and similarities of Oghuz tamgas in different written sources, the synchronicity of the existence of tamgas in the Turkic world, and how well the problem is studied.The results of preliminary research indicate the presence and preservation (based on the monuments) of Oghuz tamgas among Kazakhs, Turks, Azerbaijanis, Kirghiz, Tatars, Turkmens, Nogais, Bashkirs. This, in turn, indicates the existence of Turkic unity in the researched territories during the periods of the proliferation of Oghuz tamgas.

Continental crustal evolution and synchronous metallogeny through time in the North China Craton

The generation and evolution of continent crust have long been matters of debates. There is evidence to support the view that the first formation of TTGs of continent was possibly before 4.4 Ga, followed by the sizable continent crust associated with BIF-bearing supra-crustal rocks at ca. 3.8 Ga. Multiple stages of continental growth include continental nuclei at ~3.1 Ga, enormous crustal growth at 2.9–2.7 Ga and stabilization and cratonization at ~2.5 Ga. Subsequently a stable super-continent was formed and the Earth was evolved into the Proterozoic eon. In the Proterozoic eon, major geological events include the great oxygen event (GOE), global rift and mobile belt event, and the Earth’s middle age event with a 1.0 billion years long period of Earth’s adjustment or silence. After that, the Rodinian super-continental break up event (the Nanhua rift) and subsequent Gondwana amalgamation have been suggested to be involved with mantle-plume and the modern style-like plate tectonics, both of which are still under debates. Recent studies suggest that the continental metallogeny has secular changes with the evolving Earth, showing synchronous evolution with the continental crust through time. The North China Craton (NCC) is one of the oldest cratons in the world, and has undergone six major tectono-metallogenic cycles: (1) the Neoarchean crustal growth and Algoman-type BIFs-greenstone belt and gold metallogenic system, (2) Paleoproterozoic GOE associated with global (Huronian) rifting- Glaciation and Superior-type BIFs-Mg-B metallogenic system, (3) Paleoproterozoic rifting-subduction-accretion-collision event (mobile belt) and Cu-Pb-Zn metallogenic system; (4) Late Paleoproterozoic – Neoproterozoic multi-stage rifting and REE-Fe-Pb-Zn metallogenic system; (5) Paleozoic orogenesis at the margins of the craton and porphyry Cu-Mo metallogenic system; and (6) Mesozoic extensional tectonics associated with lithosphere thinning and intracontinental Au metallogenic systems. Ore deposit types in each of these metallogenic systems show distinct characteristics and tectonic affinities. Changes of metallogenic styles with time, from the dominant BIFs in Archean to polymetallic deposits in Proterozoic and Phanerozoic, demonstrate that the nature and style of metallogeny through time change with different stages of the Earth’s evolution and are the expression of variable materials at the different stages. The changes of metallogeny through time are controlled by the irreversible continental tectonic evolution. The connotation and signification of synchronous evolution of continental crust and mineral deposit systems through time are beyond the study of mineral resources but would provide new insights into the geodynamics of the generation and evolution of the continent. The NCC provides an excellent venue to address the linkage between metallogenic processes and secular changes in the Earth System, including mantle dynamics and crust-mantle interaction on a global perspective.