Mineralization Types of Gold in Central Inner Mongolia, China

There are four mineralization types of gold in Central Inner Mongolia: mylonite type, quartz vein type, quartzpotash- feldspar vein type and alteration type.Ore bodies of mylonite type were controlled by ductile shear zone. Both of ore and gangue minerals were undergone ductile deformation. Mineralization age is about 2040Ma and represents the metallogenetic process in deep tectonic level.There are three types of quartz veins differed from genesis mechanism. Small scaled, lens- shaped quartz veins formed during ductile shearing are found in mylonite ore bodies. Decation quartz veins are in the ore bodies of alteration type. Infiltration quartz veins are main gold- bearing bodies for some gold deposits such as Bainaimiao and Saiwusu gold mines. It also occurred in many other deposits from the middle Proterozoic to the Mesozoic.Quartz potash- feldspar veins are observed in the Palaeozoic and occurred in middle tectonic level.Gold deposits of alteration type such as Donghuofang and Saihudong occurred in shallow tectonic level of the Mesozoic.In short, from the Proterozoic to the Mesozoic, mineralization types varied from mylonite type to quartz potash- feldspar vein type and to alteration type. Gold - bearing quartz veins changed from syn - ductile - shearing quartz vein to infiltration vein and to decation quartz vein. Mineralization developed from deep to middle and to shallow level.     

Mineralization Types of Gold in Central Inner Mongolia, China

IntroductionSo - called Central inner Mongolia in the papermeans the area including Daqing Mountains, WulaMountains, Serteng Mountains and the grasslandsnorth of the mountains. Tectonically it's located inthe western part at the northern margin of the Nor…     

Geology and geochemistry of Huanggangliang stratabound skarn deposit in Inner Mongolia, China

Over the recent three decades,exploration of a large-size Sn-Fe polymetallic ore deposit at the Huanggangliang, the Da Hinggan Mountains, Inner Mongolia, China, has been largely focused on the premise that the mineralization represents epigenetic magmatic hydrothermal ore deposit in genetic connection with the Mesozoic magmatism. The Huanggangliang Sn-Fe polymetallic ore deposits occurred in Permian strata, with siltstone/marble of the Zhesi Formation and spilite/andesite/tuff of the Dashizhai Formation. The characteristics of geological and geochemical data demonstrated that sedimentary hydrothermal mineralization occurred during the basin evolution at the Permian, rather than representing epigenetic magmatic hydrothermal genesis with the following evidences. The ore-bearing skarns are stratiform with underlying metasedimentary rocks and overlying volcanic sedimentary rocks. Sedimentary hydrothermal textures and structures are observed in the stratabound ore-bearing skarn such as bedded-laminated skarn and magnetite ores with small-size folding or soft deformation, synsedimentary breccia of skarn and magnetite ores and concentric shell structure of magnetite ores. So the stratabound ore-bearing skarns associated with magnetite ore and micro-disseminated tin, are peculiar examples of exhalite. The REE contents of the stratabound ore-bearing skarns display ΣLREE-rich (36.91×10-6) but ΣHREE-depletion (6.42×10-6), with positive Eu anomaly (Eu/ Eu 1.28) and negative Ce anomaly (Ce/Ce 0.88), which is totally different from REE pattern of the Huanggang magmatic rocks(with ΣREE 277.73×10-6, ΣLREE 220.24×10-6, ΣHREE 57.49×10-6, Eu/Eu 0.06, Ce/ Ce 1.52), which is comparable with modern sea-floor hydrothermal fluid,sedimentary hydrothermal ore deposit and associated hydrothermal sedimentary rocks. Calcite samples with δ13CPDB from -5.400 ‰ to -4.397 ‰ and δ18OSMOW from 9.095 ‰ to 9.364 ‰ in the stratabound ore-bearing skarns show sedimentary hydrothermal genesis of the Huanggangliang deposit. This proposition is useful not only for interpretation of the genesis of the Huanggangliang large Sn-Fe polymetallic ore deposit but also significant for mineral exploration in the area especially for finding large deposits caused by sedimentary exhalative mineralization processes.     

Sulphur Isotope Compositions of Shibaqinghao Gold Deposit in Central Inner Mongolia, China

1 IntroductionSince the 1980, s, as a response to the upsurgein gold exploration in China, many go1d dep0sitshave been found in central Inner Mongolia. On< ofthem is Shibaqinghao gold deposit that is situate6 inBaliang Township, Guyang County, in the West…     

Pb Isotope Compositions of Shibaqinghao Gold Deposit in Central Inner Mongolia, China

There are two types of gold ore in Shibaqinghao gold deposit, a mylonite ore and a quartz - vein ore. Pb isotope compositions for mylonite ore are characterized by lower Pb isotope ratios ranging from 16.63 to 17.45 (206Pb/204Pb), 15.31 to15.48 (207Pb/204pb), 36.52 to 38.85 (208Pb/204Pb). They are scattered very close to a model curve of the mantle evolution. These ratios suggest that gold in the mylonite ore might be derived from the country rocks, which originated directly in the upper mantle. Pb isotope compositions for quartz - vein ore are characterized by higher Pb isotope ratios ranging from 18.23 to 19.74 (206Pb/204Pb), 15.69 to 15.89 (207Pb/204Pb), 38.64 to 40. 13 (208Pb/204Pb). They are scattered very close to a model curve of the upper crustal evolution. These facts indicate that the gold in the quartz - vein ore might be related to some granitic magma generated in the crust.     

Pb Isotope Compositions of Shibaqinghao Gold Deposit in Central Inner Mongolia,China

There are two types of gold ore in Shibaqinghao gold deposit, a mylonite ore and a quartz - vein ore. Pb isotope compositions for mylonite ore are characterized by lower Pb isotope ratios ranging from 16. 63 to 17.45 (206Pb/204Pb) , 15. 31 tol5.48 (207Pb/204Pb) , 36.52 to38.85 (208Pb/204Pb). They are scattered very close to a model curve of the mantle evolu-tion. These ratios suggest that gold in the mylonite ore might be derived from the country rocks, which originated directly in the upper mantle. Pb isotope compositions for quartz - vein ore are characterized by higher Pb isotope ratios ranging from 18.23 to 19.74 (206Pb/204Pb) , 15. 69 to 15. 89(207Pb/204Pb) , 38. 64 to 40. 13 (208Pb/204Pb). They are scattered very close to a model curve of the upper crustal evolution. These facts indicate that the gold in the quartz - vein ore might be relat-ed to some granitic magma generated in the crust.     

Pb Isotope Compositions of Shibaqinghao Gold Deposit in Central Inner Mongolia, China

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Sulphur Isotope Compositions of Shibaqinghao Gold Deposit in Central Inner Mongolia, China

Shibaqinghao gold deposit is situated in the western part of the northern margin of the North China Craton. It is controlled by an E - W trending tectonic zone that is located in the middle unit of Dongwufenzi group which consists of a sequence of greenschist - facies metamorphic rocks in an Archean greenstone belt.In Shibaqinghao gold deposit there are two types of gold ore, a mylonite ore and a quartz vein ore. Mylonite ore bodies were formed during ductile shearing stage in the Early Proterozoic, whereas quartz vein ore bodies might have been formed in the Mesozoic time.Pyrite accompanied with native gold in the mylonite ore has sulpfur of which δ34S values range from - 5.8 to + 0.8 per mil, similar to the values of mantle- derived sulphur. These data suggest that gold in the mylonite ore be derived from the country rocks which originated directly in the upper mantle.Pyrite in quartz vein ore has the δ34 S values between + 3.0 and + 11.0 per mil, similar to the values of some granitic rocks. These facts indicate that the gold in the quartz vein ore is related to some granitic magma generated in the crust.This study revealed that two different mineralization occurred at different geological times and in different environments but in the same place, resuling in the Shibaqinghao gold deposit.     

Estimation and Spatio-temporal Patterns of Carbon Emissions from Grassland Fires in Inner Mongolia,China

Grassland fires results in carbon emissions, which directly affects the carbon cycle of ecosystems and the carbon balance. The grassland area of Inner Mongolia accounts for 22% of the total grassland area in China, and many fires occur in the area every year. However, there are few models for estimation of carbon emissions from grassland fires. Accurate estimation of direct carbon emissions from grassland fires is critical to quantifying the contribution of grassland fires to the regional balance of atmospheric carbon. In this study, the regression equations for aboveground biomass(AGB) of grassland in growing season and MODIS NDVI(Normalized Difference Vegetation Index) were established through field experiments, then AGB during Nov.–Apr. were retrieved based on that in Oct. and decline rate, finally surface fuel load was obtained for whole year. Based on controlled combustion experiments of different grassland types in Inner Mongolia, the carbon emission rate of grassland fires for each grassland type were determined, then carbon emission was estimated using proposed method and carbon emission rate. Results revealed that annual average surface fuel load of grasslands in Inner Mongolia during 2000–2016 was approximately 1.1978 × 10~(12) kg. The total area of grassland which was burned in the Inner Mongolia region over the 17-year period was 5298.75 km2, with the annual average area of 311.69 km~2. The spatial distribution of grassland surface fuel loads is characterized by decreasing from northeast to southwest in Inner Mongolia. The total carbon emissions from grassland fires amounted to 2.24 × 10~7 kg with an annual average of 1.32 × 10~6 for the study area. The areas with most carbon emissions were mainly concentrated in Old Barag Banner and New Barag Right Banner and on the right side of the Oroqin Autonomous Banner. The spatial characteristics of carbon emission depend on the location of grassland fire, mainly in the northeast of Inner Mongolia include Hulunbuir City, Hinggan League, Xilin Gol League and Ulanqab City. The area and spatial location of grassland fires can directly affect the total amount and spatial distribution of carbon emissions. This study provides a reference for estimating carbon emissions from steppe fires. The model and framework for estimation of carbon emissions from grassland fires established can provide a reference value for estimation of carbon emissions from grassland fires in other regions.     

多极化SAR数据反演额济纳冲积扇地表参数

本文采用遗传算法和后向散射模型相结合的方法,探讨了多极化SAR(Synthetic Aperture Radar)数据反演冲积扇地表参数(地表粗糙度和土壤湿度)的可行性.通过理论模拟和实地地表测量对比,表明该方法在反演冲积扇地表参数方面是切实可行的.该方法可以根据获取数据情况不同,灵活调整反演的代价函数式,并且用于反演的SAR图像必须大于(或等于)两景,数据越多,反演结果越精确.在此基础上,利用ENVISAT ASAR数据和ALOS PALSAR数据,对内蒙古额济纳冲积扇的地表参数进行了反演计算.结果表明,额济纳冲积扇地面相对比较平坦,粗糙度参数变化较小,大部分地区均方根高度小于1.0cm.黑河沿岸地区粗糙度参数较大,而远离黑河的戈壁滩地表粗糙度较小.该地区的土壤湿度反演结果表明,该地区属于极端干旱区域,大部分地区土壤体积含水量低于10%.     

Administrative urbanization and city-making in post-reform China: a case study of Ordos City,Inner Mongolia

In post-reform China, local governments, instead of the central state, have become major promoters of urbanization. Differing from the existing literature based on Western theories, this article argues that a localized perspective, ‘administrative urbanization', can provide a contextual explanation for the mechanism of urbanization in the reform era. The case study of Ordos indicates that new town construction, especially in the inland area, has become the main strategy for investment attraction and economic development. The local government has played a dominant role in this construction through a series of administrative measures, including avoidance of central state regulations, land leasing, high standard infrastructure construction, relocation policies and industrial attraction. This article also explores the issue of unsustainability in the new town, and identifies that underdeveloped industrialization, slow population agglomeration and real estate bubbles are primary threats to the sustainability of administrative urbanization.     

Effects of plant types on physico-chemical properties of reclaimed mining soil in Inner Mongolia,China

A field experiment was conducted in Jungar Banner, Inner Mongolia, China to study the effects of plant types on the physical structure and chemical properties of open-cast mining soils reclaimed for 15 years, and to analyze the triggering factors of the soil formation. Results indicate that plant types affect soil-forming process especially in the upper layer (0–20 cm), and the spatial structure of reclaimed plant is the main reason for variability of the soil-forming process. In the upper soil layer at the site reclaimed with mixed plants, the concentrations of soil organic matter (SOM) and soil organic carbon (SOC) are the highest, and they were significantly higher at the sites reclaimed with Leymus chinensis, Caragana sinica, which is mainly due to a large amount of litter fall and root exudation in herbages and shrubs. However, the concentrations of SOM and SOC in the soils at the reclaimed sites are quite low comparing with those in local primary soil, which indicates the importance of using organic amendments during the ecological restoration in the study area.     

Effects of grazing exclusion on soil carbon and nitrogen storage in semi-arid grassland in Inner Mongolia,China

The semi-arid grasslands in Inner Mongolia, China have been degraded by long-term grazing. A series of ecological restoration strategies have been implemented to improve grassland service. However, little is known about the effect of these ecological restoration practices on soil carbon and nitrogen storage. In this study, characteristics of vegetation and soil properties under continued grazing and exclusion of livestock for six years due to a nationwide conservation program—′Returning Grazing Lands to Grasslands(RGLG)′ were examined in semi-arid Hulun Buir grassland in Inner Mongolia, China. The results show that removal of grazing for six years resulted in a significant recovery in vegetation with higher above and below-ground biomass, but a lower soil bulk density and pH value. After six years of grazing exclusion, soil organic C and total N storage increased by 13.9% and 17.1%, respectively, which could be partly explained by decreased loss and increased input of C and N to soil. The effects of grazing exclusion on soil C and N concentration and storage primarily occurred in the upper soil depths. The results indicate that removal of grazing pressure within the RGLG program was an effective restoration approach to control grassland degradation in this region. However, more comprehensive studies are needed to evaluate the effectiveness of the RGLG program and to improve the management strategies for grassland restoration in this area.     

Palynological record of paleovegetation change during holocene at North tumd plain in Inner Mongolia, China

I~are~orsruDVThemiddleinnerMongoliaissituatedintherearpartoftheeasternAsianmonsonzone,itissensitivetotheclimatechange,thereforeitsenvironmentchangeintheHOIOcenehasbeenPaidattentiontobythescholarsofpaleoclimateandpal~nvirorunent.Wedidhighr~lutionPOllenanalysisonapeatprofileinpluvialfan,whichwaslocated3kmtothenorthOfQaSq,theheadquarteroftheTumdBanner,InnerMongolia,withaltitudeof1000malerssealevel.Theaverageannualtemperaturewas5.6t,annualprecipitation300--450rum,theclimatewascontinentaland…     

内蒙古河套地区地球化学分区及特征

土壤中元素含量的高低和元素存在的形态变化从根本上受控于自然地质地球化学作用过程。地质背景对土壤地球化学元素含量的贡献度在区域上具有决定意义,不同区域土壤地球化学元素含量水平具有明显的差别。不同的地貌景观是由不同的地质作用形成,从而形成不同的地球化学特征。在多目标区域地球化学调查的成果基础上,根据因子分析、聚类分析研究成果,结合与典型元素组合、地貌、地质特征把河套地区划分为9个地球化学分区,并进一步划分为13个地球化学亚区。通过地球化学分区,为河套地区的农业发展、环境保护等工作提供了基础地球化学资料。      

Spatio-temporal variation of wind erosion in Inner Mongolia of China between 2001 and 2010

Using Geographic Information System(GIS), based on wind speed, precipitation, topographic, soil, vegetation coverage and land use data of Inner Mongolia between 2001 and 2010, we applied the revised wind erosion equation(RWEQ) model to simulate wind erosion intensity. The results showed that an area of approximately 47.8 × 10~4 km~2 experienced wind erosion in 2010, 23.2% of this erosion could be rated as severe, and 46.0% as moderate. Both the area and the intensity of wind erosion had decreased from 2001 to 2010, the wind erosion area reduced 10.1%, and wind erosion intensity decreased by 29.4%. Precipitation, wind speed, population size and urbanization in rural areas, and gross domestic product of primary industry(GDP1) were the main factors influencing wind erosion. Overall, these factors accounted for 88.8% of the wind erosion. These results indicated that the decrease in wind erosion over the past decade related to the increase in precipitation and the decrease in the number of windy days, while modest urban development and optimization of the economic structure might partially reduced the level of ecological pressure, highlighting the importance of human activities in controlling wind erosion.     

内蒙古渣尔泰山群地层地球化学特征及含矿性

在充分研究已有资料的基础上,通过野外实地调研,以内蒙古中西部渣尔泰山地区为主要研究对象,对渣尔泰山群地层进行了划分,并探讨了该地层地球化学特征,最后就该地层含矿性进行了评价。结果表明:中元古界渣尔泰山群为一套浅变质岩系,属裂谷系中的碎屑岩、炭质页岩、粉砂岩和碳酸盐岩建造,自下而上分为书记沟组、增隆昌组、阿古鲁沟组和刘鸿湾组,主要含矿层为阿古鲁沟组;渣尔泰山群沉积环境呈现由陆相→正常海相→半封闭海相或次深海相→滨海相的正常海进海退序列变化特征;渣尔泰山群地层在纵向上自下而上表现为亲碎屑元素组合→亲碳酸盐元素组合→亲铁、亲硫元素组合→亲碳酸盐、亲碎屑岩的混合组合;岩石组分与成矿元素有显著相关性,泥质、钙镁质岩富含铅、锌及硫铁,高硅质岩石富含铜,有机碳含量往往与矿层的规模、质量成正消长关系;不同的构造演化阶段和沉积环境致使元素分布不均匀,体现在含矿性在东西走向的规律性变化,即东部甲生盘—山片沟矿床贫铜富锌,少伴生元素,而西部狼山地区铜、铅、锌共生,贫铅锌富铜,伴生元素较多。     

Geological significance of componential characteristics of pyrite from Shibaqinghao gold deposit in central Inner Mongolia, China

There are two types of gold ore in Shibaqinghao gold deposit, mylonite ore and quartz vein ore. Pyrite accompanying with native gold in mylonite ore has Fe from 43.66 to 45.32 wt% and S from 52.64 to 53.55 wt%. It is clear that this kind of pyrite is poor in both sulphur and iron. That means that the mylonite ore may be related to metamorphic water. Pyrite in the quartz vein ore has Fe from 44.38 to 45.30 wt% and S from 53.08 to 54.00 wt%. It means that this kind of pyrite is poor in iron but rich in sulphur, while the quartz vein ore may be related to magma water.     

Geological significance of componential characteristics of pyrite from Shibaqinghao gold deposit in central Inner Mongolia, China

1Geologic settingThe Shibaqinghao gold deposit is situatedinthemiddle part of Serteng Mountains,Inner Mongolia.Geotectonic placeislocatedinthe western part of thenorthern margin of the North China Craton.Dongwufenzi Group that is the country rocks ofShibaqinghao gold deposit is composed of green-schist-facies metamorphic rocks.According to thestudy(Liuet al,1987),the proto rocks of Dong-wufenzi Group are assumed to be ultramafic volcanicrocks(komatiite),tholeiitic and alkali basalts,sili…     

Chracteristics and formation setting of granodiorite in Zhalute County, Inner Mongolia

Based on field investigation and study of petrology, mineralogy, geochemistry and isotopic geochronology for the granodiorite, the authors discussed the formation setting of the granodiorite. The pluton is calci alkalic and peraluminous granite in which light rare earth elements (LREE) are intensively enriched, heavy rare earth elements are relatively poor, the ratio of LREE to heavy rare earth elements (HREE) is 7. 12, and the fractionation of REE is good. The pluton formed in late orogenic setting which is relatively steady.