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The gold mineralization of the North China Craton (NCC) is not uniform. This inhomogeneity mainly is reflected by the spatial dispersity and local concentration，and the multi­periods of gold-forming. Gold deposits are mainly converged in Jiaodong， western Shandong， Xiaoqinling， Xiong’er Mountain， eastern Hebei， western and eastern Liaoning and southern Jilin. The northern margin of the NCC is strongly enriched in Au, Mo and Cu, and the southern margin is enriched in Au and Mo, while the eastern margin is characterized by Au. Early period is Au-M〇-Pb-Zn combination, the peak is Au, and the late is Au-Ag combination. Early Cretaceous is the main gold metallogenic epoch of the NCC, then is the Middle-Late Triassic and Jurassic. Generally, the gold mineralization time of Xiaoqinling, Xiong^r Mountain and Taihang Mountain is a little earlier than Jiaodong gold deposit; Jinchangyu, Yu：erya and Niuxinshan gold deposits in the eastern Hebei, as well as Baiyun and Maoling gold deposits in the western Liaoning are formed in Triassic-Jurassic. Overall, the inhomogeneity of gold deposits in the NCC is characterized by the differences of the ore-forming time. The uneven distribution of the NCC gold deposits is comprehensive controlled by the tectonic evolution and interaction of the regional geological bodies, the hydrothermal alteration and gold activation and migration of the metamorphic basement, and the Mesozoic magma activity. In the Middle Jurassic and before, the tectonic evolution of the NCC is mainly influenced by the Central Asian orogenic belt and the Qinling-Dabie orogenic belt. The northern margin of the NCC occurs the transition from extrusion to extension, and in local develops mantle upwelling and lithospheric thinning, and a series of Triassic to Early Jurassic magmatic activities along the EW direction, and even the presence of alkaline rocks, generating a series of Au-M〇-Cu deposits. This is the first craton destruction and gold mineralization event that occurred in the northern margin after the formation of the NCC. In the Cretaceous and after, the geological evolution of the NCC is mainly led by the ancient Pacific Plate. The NCC is subjected to the extensive lithospheric thinning which leads to a more large-scale gold mineralization. In addition, it is found that the ore-forming materials supplied from the metamorphic rock is not entirely dependent on the gold content? but depends on one or more geological processes, which activate and extract gold in the wall-rock, and transport in the hydrothermal fluid, and enrich in a suitable tectonic environment. The influence of granitoids and intermediate-mafic dike rocks in gold deposits seems like a “hot machine’’，which is the source of metallogenic hydrothermal fluid (magmatic fluid) , and is also a possible source of some ore-forming minerals. [ABSTRACT FROM AUTHOR]

The metallogenic belt is a geological unit for possessing potential of ore resources. The metallogenic system mainly focuses on the overall characteristics of mineralization from the aspects of metallogenic elements and processes, including deposit assembly, metallogenic series and their original link. The metallogenic system is an important evidence for dividing metallogenic belt and summarizing metallogenic regularity. East Tianshan orogenic belt, which is sandwiched between Tuha Basin and Tarim block, may be divided into four metallogenic belts in terms of spatial distribution, including Dananhu-Tousuquan Cu-Au-polymetallic metallogenic belt, Kanggurtag-Huangshan Au-Cu-Ni metallogenic belt, Aqishan-Yamansu Fe-Cu-polymetallic metallogenic belt and Caixiashan-Jiyuan Pb-Zn-Ag-polymetallic metallogenic belt. The temporal evolution of East Tianshan orogenic belt is distinctly characterized by multi-stage and multiple metallogenic system, including ① Middle-Late Proterozoic extension continental margin, where there occurs a metallogenic system of sedimentation Pb-Zn-Ag deposits; ② Ordovician-Carboniferous active continental margin, where there occurs a metallogenic system of VMS Cu-Zn deposits and porphyry Cu deposits; ③ Carboniferous island arc, where there occurs a metallogenic system of volcanic Fe-Cu deposits; ④ Late Carboniferous-Early Permian post-collision orogeny and superimposition of mantle plume, where there occurs a metallogenic system of magmatic Cu-Ni deposits and a metallogenic system of Au deposits related to ductile shear processes. [ABSTRACT FROM AUTHOR]

Based on the studies of the geological evolution, field investigation of the ore-bearing rock series, zircon U-Pb isotope chronology and typical iron ore deposits of Taxkorgan Block in West Kunlun, the characteristics and forming ages of regional ore-bearing formation, ore deposit type and metallogenic regularity were summarized. The results show that the previously defined “Bulunkuole Group” actually contains Paleoproterozoic (2 100-2 500 Ma) and Early Cambrian (510-540 Ma) sedimentary metallogenic events, which are suffered to the intensely metamorphism and deformation in both Middle-Late Proterozoic (800-1 800 Ma) and Hercynian-Indosinian (200-410 Ma). Moreover, the genesis of the local high-grade ores may be related to the later hydrothermal activities. The regional iron deposits can be divided into two types. The first one is the meta-sedimentary type iron deposit that is superimposed and transformed by the later hydrothermal fluids; taking Zankan, Mokaer and Jiertiekegou as examples, they form in weakly oxic to reducing marine sedimentary environment of Early Proterozoic active continental margin and the metallogenetic materials are derived from the leaching of basic volcanic rocks by seafloor hydrothermal fluids and a small amount of terrigenous sediments input. The second type is the Early Cambrian marine volcanic exhalative sedimentary iron deposit, such as Kalaizi, Laobing and Yeleke sulfate-iron deposit; their depositional environment should be bathyal-neritic facies weakly oxic to suboxic faulted basin; and the ore-forming materials come from the submarine hydrothermal sedimentary and terrigenous materials input. According to the regional metallogenic regularity, it is speculated that Kalaben-Kalaizi-Molahe belt is the favorable area for prospecting the iron-polymetallic deposits, which associate with the Early Cambrian marine exhalative metallogenic system. While, Jiertiekegou-Zankanbei area, Mokaer and its southern area, which are the northward and southward extensional zones of Zankan iron ore belt, are both the favorable areas for prospecting the meta-sedimentary type of Paleoproterozoic iron deposits. [ABSTRACT FROM AUTHOR]

As a clean and renewable energy, hot dry rocks are the most potential part of exploiting and utilizing in the future, and the engineering technology of exploiting hot dry rock is called enhanced geothermal system. As a supplementary method of hydrofracture, chemical stimulation technology has the characteristics of low cost and risk, and plays a very important role in optimizing reservoir reform. Some related literatures at home and abroad about chemical stimulation technology in enhanced geothermal system（EGS）were reviewed, and the theoretical basis of chemical stimulation technology and several common chemical stimulants（conventional acid, retarded acid, chelating agent and CO2 chemical stimulants）were presented. In addition, the only EGS projects（Fenton Hill in America and Soultz in France）applying chemical stimulation technology in the world were introduced and summarized. On this basis, several suggests and expectations about chemical stimulation in EGS were also proposed, hoping to provide a reference for the scientific research and project implementation of EGS in China. [ABSTRACT FROM AUTHOR]