Abstract:The previous geological research work in the Yangtze River Economic Zone is systematically summed up and arranged in this paper. Resources and environment conditions and major geological problems which have aroused much attention in the construction and the territorial planning in the Yangtze River Economic Zone are studied. The research results show that the resource conditions of cultivated land, shale gas, geothermal resources, llithium etc. are very favorable in the Yangtze River Economic Zone:30 million hm² farmlands without heavy metal pollution exhibit concentrated distribution; there are three national shale gas exploration and development bases with explored reserves of 544.1 billion cubic meters; available geothermal resources amount to 240 million tons of standard coal per year, equivalent to 19% of the amount of coal consumption in 2014; the largest energy lithium metal ore deposit in Asia was found; resources and environment conditions are favorable for the development of modern agriculture industry, clean energy and strategic emerging industries. Nevertheless, in some parts of the Yangtze River Economic Zone, there exist some major geological problems such as active faults, karst collapse, ground subsidence, and landslide-collapse-debris flow, which affect the river-crossing channels, high-speed railway, urban groups and green ecological corridor planning and construction. The authors point out that these problems deserve much attention. For this, the relevant suggestions and countermeasures are put forward. At the same time, the paper puts forward the idea of further supporting the development of the Yangtze River Economic Zone.

Abstract:Due to the superiority of high energy efficiency and environmental friendliness, shallow geothermal resources have been widely applied in recent years in China. Geological conditions, characteristics of shallow geotemperature field and thermophysical parameters of rocks and soils are important parameters for shallow geothermal resources. Based on relevant research on nationwide investigation and evaluation of shallow geothermal energy resources in 31 provincial capital cities in China, the authors evaluated the characteristics, resources and regional development planning of shallow geothermal resources in China. The results show that, in constant temperature zone, feature temperature is mostly affected by solar radiation, and the trend of buried depth is opposite to temperature change. What's more, thermal conductivity of soils and rocks is obviously influenced by lithology. The most important application of shallow geothermal resources is for heating and cooling in buildings. Over 80% of the provincial capital cities are suitable for shallow geothermal utilization and annual exploitable shallow geothermal resources of 31 provincial capital cities are equivalent to 280 million tons of standard coal, which is abundant for heating and cooling. Considering the way of utilization and the level of demand, the authors divided whole China into four types of areas, i.e., centralized utilization area (both heating and cooling), distributed utilization area (both heating and cooling), distributed utilization area only for heating and distributed utilization area only for cooling. The development and utilization of shallow geothermal resources are of great significance for promoting the development of China's green, low-carbon and energy-saving urbanization and can also solve the problem of winter smog in the Beijing-Tianjin-Hebei region and satisfy the demand of heating in winter in cities of southern China..

Abstract:Haze in Beijing-Tianjin-Hebei region is relatively heavy; at the same time, this region is rich in geothermal resources. The development of geothermal resources can contribute to the energy structure adjustment and the control of haze in that region. In this paper, based on the analysis of the fracture, strata, terrestrial heat flow and geothermal gradient of Beijing-Tianjin-Hebei region, the authors summed up the formation mode and hosting conditions of convection geothermal and conductive geothermal resources respectively. The quantity, exploitation situation and the development potential of geothermal resources were also calculated. The result shows that geothermal resource reserves are equivalent to about 138.3 billion tons of standard coal, and heat in geothermal fluid of the local region amounts to about 11 million tons of standard coal. Nevertheless, the exploitation quantity is only equivalent to about 10% of the total resources, and hence the potential for geothermal resources development and utilization is huge.

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Abstract:In recent years, urban geological survey has been carried out in some city groups, big cities and small towns of China and, as a result, obtained great achievements in survey and evaluation of urban geological resources, geological environment, urban development space, and system construction of geological information service in urban management and some other aspects, and gained some experience in the survey methods, products, services, and coordination mechanism. However, compared with the requirements of new urbanization, there are still many shortcomings, such as backward work concept, slow updating of geological information, lack of standard systems, and imperfect working mechanism. In the national new urbanization development strategy, a new concept on urban development has been proposed. Urban geological survey is imperative to support the optimization of city layout structure, the expansion of urban development space, the promotion of green city construction, the improvement of city safety level and so on. In the new period, urban geological survey should be carried out with new ideas and the concept of big resources, big environment and big data. A comprehensive survey, which includes space, resources, environment, disaster and other factors, is required to serve urban planning, construction, operation, management and some other aspects. It also needs the development of three-dimensional visualization underground geological model for cities (transparent cities), the improvement of monitoring networks on geological resources and environment, the establishment of an open, shared and dynamic updating city geological information service and decision support system, the development of service product system, urban geological survey technical standard system and security system. In order to achieve this goal, it is necessary to establish the theory on urban resources and environment carrying capacity, urban multi-layer interaction zone and underground space resources collaborative planning so as to study and solve these technical difficulties encountered in urban geological exploration and monitoring, geological suitability evaluation for land space development, geological safety assessment for underground space development and utilization, 3D urban geological modeling and public services, and so on.

Abstract:The structural zone of the western Pacific margin is the biggest and most complex plate boundary in the earth. Bounded at Taiwan and the Molucca Sea, it can be divided into 3 sections from the north to the south. The north part, from Kurile to Ryukyu, is a typical trench-arc-basin system, and Kurile basin, Japan Sea and Okinawa trough constitute back arc basin. The central part, the Philippine structural zone, is characterized by complex double subduction. It underwent large displacement and reconstruction in Cenozoic and resulted in much debate for the origin of the South China Sea, Sulu Sea and Celebes Sea. The south part, the New Guinea-Solomon structural zone, resulted from compression and collision among Pacific, Indian and Eurasian plate, with large amounts of strike and back arc spreading. There are new spreading basins and subducting basins among the structural zones. The Taiwan Island is located at the junction, in which the Eurasian plate was torn. Eurasian plate margin subducted eastward beneath the Philippine arc along Manila Trench in the south, while Philippine Sea plate subducted northeastward beneath Eurasian plate along Ryukyu Trench in the north. Molucca Sea is another junction on the west Pacific margin, in which the oceanic lithosphere plate subducted westward beneath Sangihe arc and eastward beneath Halmahera arc, forming reversal U-shaped double subduction zone. Halmahera arc collided with Sangihe arc due to the almost disappearance of the oceanic plate.

Abstract:The North China Plain (NCP) is one of the biggest groundwater systems in the world, and land subsidence occurs commonly. Due to diverse sedimentary environments, different geological conditions, and intensive groundwater exploitation, the mechanism of land subsidence is complex. With the help of earth observing technique and traditional monitoring tools, the disaster process of land subsidence was monitored, and the developing history and current situation were analyzed. Combined with strainstress diagrams and soil mechanics tests, the difference features of land subsidence and the mechanism of hysteretic deformation were analyzed. Some conclusions have been reached:(1) The spatial distribution of land subsidence is significantly distinct. The land subsidence areas are mainly located in the areas of the Quaternary sedimentary depressions, having characteristics of west-east sub-zone and north-south subsection. The spatial development of land subsidence is partially controlled by NE-and NW-trending structures. The land subsidence in the Cangxian uplift is serious in that the tectogenesis is relatively inactive in Quaternary and the loose sediments are very thick. Also, there exist paleochannels of three layers with the same strike as the structures, whose groundwater resource is abundant and has been intensively exploited. (2) The development of subsidence is correlated with the local groundwater exploitation history, and the major contribution layers to the land subsidence have varied with the change of exploited layers. The contribution of the strata below 100m has increased in the Beijing plain. The land subsidence of the Tianjin plain mainly comes from the compression of the strata below 300 m. (3) The drought is an important and indirect factor leading to subsidence by reducing natural recharge and leading to the increase of groundwater exploitation for emergency water supply. Besides, in the groundwater exploitation, much attention should be paid to the effect of the heavy weight of densely constructed buildings, dewatering of foundation pits, and the exploitation of deep geothermal water.(4) The hysteresis of land subsidence is obvious, and the time of hysteresis can last for twenty-five years. Besides the consolidation, the creep is another important reason for the hysteresis. The creep is obvious for the Pleistocene strata, which can reach 28.3% of the total deformation for the Late Pleistocene strata in the Cangxian uplift. (5)The deformation characteristics of the soil layer bear strong relationship to the physical characteristics and change pattern of groundwater levels. The strata at different depths have distinct deformation characteristics such as elastic, visco-elastic, and visco-elastic-plastic deformations. Shallow aquifer groups indicate typical elastic deformation.

Abstract:Geothermal resources in Beijing belong to middle-low temperature geothermal resources, which have experienced more than 50 years of concentrated development and utilization. After years of development and utilization, there have occurred some highlighted environmental geological problems in Beijing. In order to reasonably determine the direction of the development and utilization of geothermal resources in Beijing and to build a livable city, this paper summarizes the distributive characteristics of these resources by analyzing the features of geotemperature, hydrogeochemical and stable isotope characteristics. It is found that the geothermal reservoir with the roof temperature higher than 80oC is mainly located in the center of Beijing depression and near the Fengheying in the southern part of Daxing superimposed uplift, and the water chemistry type in Beijing is mainly HCO₃~Na type. The authors also put up zonation for geotemperature regionalization, geothermal resources exploitation and utilization as well as potential regionalization. The geothermal resources protection regionalization is based on the division of the geothermal fields, the characteristics of geothermal resources in combination with the exploitation degree, resource conditions and regional economic development requirements. The region can be divided into restricted mining area, control mining area, mining area and other areas, with the respective area being 378.65 km², 562.88, km²,1612.07 km², and 3722.31 km². The results obtained by the authors are of great significance for understanding the overall characteristics of the geothermal resources and the sources of geothermal water supply and for formulating the geothermal utilization planning. The results also has a guiding significance for protection and exploitation of geothermal resources.

Abstract:Granites genetically related to tin ore deposits always constitute the focus of geological studies. The Lailishan granitoids are located in the Tengchong-Lianghe area of western Yunnan and belong tectonically to Tengliang granitoids. These granites extend in NNE direction as a belt, connected with Gangdise belt on the north. The Lailishan granitoids are mainly composed of porphyaceous biotite monzogranite and medium to coarse-grained biotite syenogranite. Based on the data available, the authors conducted petrological, geochemical and geochronological studies of the Lailisahn granitoids. The zircon LA-ICP-MS U-Pb age of the monzogranite (14L-4) is 52.34 ±0.68Ma (MSWD=1.4, n=26). Geochemically, the monzogranite is relatively rich in Al (Al₂O₃=14.70%-15.27%), alkalis (K₂O+Na₂O=8.07%-8.50%), Ca (CaO=1.64%-2.56%), REE, and Ba. The ASI values range from 0.97 to 1.12, 1.04 on average, indicating that monzogranite is from metaluminous to weakly peraluminous. The syenogranite is relatively rich in Si (SiO₂=74.57%-76.69%) and Rb, and strongly depleted in Ba, Sr, P, Ti, and Eu. The ASI values range from 1.05 to 1.18, 1.09 on average, indicating weakly peraluminous features. The monzogranite and syenogranite originated from the same magma reservoir but emplaced at different stages; the evolution of them in mineralogy, geochemistry and chronology was obvious, suggesting S-type granites. It is therefore held that the Lailishan granitoids originated from crust partial melting in deep crust during main Indian-Euro-Asian collision period, responding to the interaction between the Indian-Euro-Asian continents.

Abstract:Baoligaomiao Formation is outcropped in Bayan Aobao Town of East Ujimqin Banner,Inner Mongolia. It can be divided into three segments corresponding to the second, the third and the fourth section of Chaganaobao. The second segment comprises a set of variegated intermediate-acidic volcanic lava and volcanic clasts. Volcanic eruption is mainly as extrusive facies. The third segment includes a set of Annularia fossil-bearing grayish yellow, grayish white volcanic sedimentary clasts and terrigenous sediments, being an intermittent volcanic deposit; the fourth segment has a set of gray, light-gray acidic lavas containing rare volcanic-clastic sedimentary rock. Volcanic eruption is mainly as extrusive facies. The fourth segment includes purplish red crystal rhyolite, and the second segment is grayish black rhyolite with granite age being (305±4.1) Ma and (315.2±4.6) Ma. Isotope age and the fossils suggest that the stratigraphic age is late Carboniferous to early Early Permian. Baoligaomiao Formation has intermediateacidic volcanic rock, with separate andesitic, dacite, high-K calc-alkaline to Shoshonis series volcanic association. Major elements are characterized by enrichment of SiO₂ and alkali and depletion of calcium and magnesium. Indexes of A/NK and FeO^t/MgO are high, characterized by enrichment of Rb, Nb and depletion of transition group elements, with dramatic Eu negative anomaly, suggesting A2 type sub-granite. It was probably the magma from the mantle and partly from conglomerate substance of the lower crust in late Paleozoic. Magmatic evolution experienced dissociation to produce titanium iron minerals, ferromagnesian minerals, and plagioclase. The intermediate-acidic volcanic rock in Baoligaomiao Formation was formed in a post-collisional setting. Its characteristics reveal that Xing'an-Mongolian orogenic belt of East Ujimqin Banner was in the syn-collision to post-collision stage during late Carboniferous to early Permian period. In Early Permian, the evolution entered a stage of stretching after collision.

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Abstract:Kangding metamorphosed intrusions in Kangding, Mianning and Panzhihua areas of Sichuan Province and Yuanmou area of Yunnan Province were formed in the island arc setting, as shown by the integrated study of petrogenesis and Hf isotopic geochemistry of plutonic rocks ranging from acid to basic ones. Zircons from the mafic plutons have ε_Hf(t) values ranging from -4.2 to +11.0, with their Hf model ages ranging from 742 to 2386 Ma. The felsic plutons have ε_Hf(t) values ranging from -4.9 to +9.4, with their Hf model ages ranging from 967 to 2707 Ma. Magmatic zircons from the Kangding intrusive complexes show similar Hf isotope compositions to those from coeval felsic intrusions on the west margin of the Yangtze Craton, implying their similar magmatic origins. The Kangding intrusive complexes were formed in an oceanic subduction setting, the mafic plutons were derived from depleted mantle sources, whereas the felsic plutons were formed by melting of ancient crustal materials and juvenility crustal materials. According to the Nd isotopic data of the whole rock and the Hf isotopic data of the corresponding zircons in this area, the Hf-Nd decoupling must have resulted from the "zircon effect" and crustal material interaction. Petrology, stratigraphic correlations, tectonic analysis and geochemical evidence suggest that the Yangtze block of South China was located along the margin of the Neoproterozic supercontinent Gondwana rather than at the connection between Australia and Laurentia old land in North America.

Abstract:The Ordos Basin is an important large basin with multi-energy resources, around which a series of sandstone-type uranium deposits are developed. The Nalinggou uranium deposit located in the northeastern part was chosen as a study object. Five sandstone samples surrounding the ore-bearing segment in the Zhiluo Formation were selected to make detrital zircon U-Pb dating, while electron microprobe analysis was performed for some sandstone samples with uranium minerals. The ages are distributed as 5 major peaks:(2479±11) Ma-(2460±19) Ma, (2300-1950)Ma, (1896±21) Ma-(1820±32) Ma, (316-266) Ma and 165 Ma. The authors further arranged the age data of metamorphosed basement, khondalite belt and Late Paleozoic intrusions in the orogenic belt on the north margin of the Ordos Basin. These zones of detrital zircons ages are consistent with the ages of geological bodies in the orogenic belts on the northern margin of the Ordos Basin. Combined with the previous work about geochemistry and paleogeography, the authors hold that the provenance of sandstone of Zhiluo Formation in Nalinggou area was finally derived from the orogenic belt on the northern margin of the Ordos Basin. The uranium minerals are spread in and around the clastic grains, clay minerals, pyrites, and fractures in charcoal fragments. The radioactive anomaly measurement in the field work shows that the uranium source probably came from the pre-enrichment of clastic grains from the provenance at the diagenetic stage, and from the migration of the uranium-and oxygen-bearing water through later leaching of the highly radioactive bodies of the provenance.

Abstract:Mafic-ultramafic rocks in Xiangshan are located in Huangshan-Jingerquan mafic-ultramafic rock zone in east Tianshan Mountains, Xinjiang. The main rock types are iherzolite, (containing feldspar) clinopyroxene peridotite, olivine pyroxenite and hornblende gabbro. According to the mineralogical characteristics, the rock mineral crystallization sequence is in order of chrome spinel, olivine, orthopyroxene, clinopyroxene, plagioclase, and angle amphibole. In the same period, the transition of the lithofacies in each stage of the invasion period has a good transition. The content of olivine in the drilling section and the composition of the particles and the composition of the particles in the drilling section vary with depth. The evolution of Cr→Fe³⁺, Ti in picotite is good. According to these features, the formation of the rock mass is mainly controlled by the crystallization differentiation. Abrupt change of olivine and the composition of the olivine in the (feldspar-bearing) clinopyroxene show the existence of crustal mixture in the process of magma crystallization. The simulation results show that the crystallization of olivine was accompanied by the melting of the sulfide. At the depths of 295-325 m in ZK3693 borehole, abrupt change of the composition of (feldspar-bearing) clinopyroxene in the olivine, plagioclase, single grain clino-feldspar and the Al→Cr evolution of the Cr spinel indicates that there is a higher basic level of magma injection in the interval. The Cu and Ni grades of the ore in this area are obviously higher than those of the same rock mass which is not in the interval. That injection of fresh magma is an important cause of the sulfide enrichment in Xiangshan.

Abstract:Located in the southwestern part of Gan-Hang tectonic zone and closed to the Xiangshan uranium orefield, the largest volcanic-type uranium orefield in China, the Yuhuashan area is a significant prospective prediction area for uranium ore deposit. In this paper, a systematic study of uranium metallogenic conditions such as metamorphic basement, magmation, fracture structure, and hydrothermal activity indicates that Yuhuashan area is an excellent potential area for uranium mineralizaiton. Compared with the Xiangshan uranium orefield, they have many great differences in such aspects as the degree of volcanic activity, the degree of late hydrothermal activity, and the denudation degree. The geochemical and geophysical anomalies of Yuhuashan area indicate that the area within the comprehensive anomaly of U -Th -Mo, the alternate magnetic positive and negative anomalies and positive radioactive anomalies are favorable areas for uranium exploration. Based on the ore-forming geological, geochemical and geophysical conditions, the authors established a comprehensive anomaly model and a uranium exploration model for Yuhuashan area, which will provide important theoretic and practical reference for uranium exploration in the future. Moreover, the authors hold that more exploration work should be preferentially carried out along the Weishan-Tongshan fault zone which is the key position of resource reserves.

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