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摘要:Deep mineral exploration is increasingly important for finding new mineral resources but there are many uncertainties. Understanding the factors controlling the localization of mineralization at depth can reduce the risk in deep mineral exploration. One of the relatively poorly constrained but important factors is the hydrodynamics of mineralization. This paper reviews the principles of hydrodynamics of mineralization, especially the nature of relationships between mineralization and structures, and their applications to various types of mineralization systems in the context of hydrodynamic linkage between shallow and deep parts of the systems. Three categories of mineralization systems were examined, i.e., magmatic-hydrothermal systems, structurally controlled hydrothermal systems with uncertain fluid sources, and hydrothermal systems associated with sedimentary basins. The implications for deep mineral exploration, including potentials for new mineral resources at depth, favorable locations for mineralization, as well as uncertainties, are discussed.

摘要:This is a review of the formation and tectonic evolution of the continental Asia in Phanerozoic. The continental Asia has formed on the bases of some pre-Cambrian cratons, such as the Siberia, India, Arabia, North China, Tarim, South China, and Indochina, through multi-stage plate convergence and collisional collages in Phanerozoic. The north-central Asia had experienced the expansion and subduction of the Paleo-Asian Ocean (PAO) in the early Paleozoic and the closure of the PAO in the late Paleozoic and early Mesozoic, forming the PAO regime and Central Asian orogenic belt (CAOB). In the core of the CAOB, the Mongol-Okhotsk Ocean (MOO) opened with limited expansion in the Early Permian and finally closed in the Late Jurassic–Early Cretaceous. The south-central Asia had experienced mainly multi-stage oceanic opening, subduction and collision evolution in the Tethys Ocean, forming the Tethys regime and Himalaya-Tibetan orogenic belt. In eastern Asia, the plate subduction and continental margin orogeny on western margin of the Pacific Ocean, forms the West Pacific regime and West Pacific orogenic belt. The PAO, Tethys, and West Pacific regimes, together with Precambrian cratons among or surrounding them, made up the major tectonic and dynamic systems of the continental Asia in Phanerozoic. Major tectonic events, such as the Early Paleozoic Qilian, Uralian, and Dunhuang orogeneses, the late Paleozoic East Junggar, Tianshan and West Junggar orogeneses, the Middle to Late Permian Ailaoshan orogeny and North-South Lhasa collision, the early Mesozoic Indochina-South China and North-South China collisions, the late Mesozoic Mongolia-Okhotsk orogeny, Lhasa-Qiangtang collision, and intra-continental Yanshanian orogeny, and the Cenozoic Indo-Asian, Arab-Asian, and West Pacific margin collisions, constrained the formation and evolution of the continental Asia. The complex dynamic systems have left large number of deformation features, such as large-scale strike-slip faults, thrust-fold systems and extensional detachments on the continental Asia. Based on past tectonics, a future supercontinent, the Ameurasia, is prospected for the development of the Asia in ca. 250 Myr.

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摘要:The Sichuan Basin, also known as the ‘Red Basin’, is famous for its abundance of Mesozoic dinosaur fossils, especially in the Zigong area during the Jurassic era; the Middle Jurassic Shunosaurus and the Late Jurassic Mamenchisaurus faunal assemblages are the most representative. The Qinglongshan dinosaur fossil site is located in Fuxing, to the northwest of Rong County, Zigong City. This new site is situated within the Middle Jurassic Xiashaximiao Formation, and geologically is roughly equivalent to the well-known Dashanpu dinosaur fossil site. More than 600 dinosaur fossils were found concentrated in the excavation area, including teeth; cervical, dorsal and caudal vertebrae; and various parts of appendicular skeletons. This fossil site is also most significant as it provides new information on non-avian dinosaur life during the poorly understood Middle Jurassic.

摘要:Fourteen species of nonmarine gastropod opercula are found to be in high abundance in the Oligocene upper member of the Yehucheng Formation, Lanzhou Basin, northwest China. They are attributed to two families, namely Bithyniidae and Assimineidae, and four genera, namely Pseudemmericia, Bithynia, Mirolaminatus and Assiminea. Among them, three species are new, and they are Bithynia paramonolithic sp. nov., B. obliquus sp. nov., and B. disregularis sp. nov. Some of these species were first discovered in Paleogene strata of the vast Northwest China and can be compared with the opercula recovered from the Paleogene deposits in East and South China. It is inferred from the paleontology and sediment associations that the climate was slightly humid and the fauna probably inhabited the fresh or brackish water of a shallow lake in the Lanzhou Basin during the late early Oligocene period.

摘要:The Mariana subduction structure is a hot topic in ocean-ocean subduction zone research, and its subduction mechanism has attracted wide attention from experts and scholars in China and abroad. Based on the multi-channel seismic data of survey line MGL1204 in the Mariana fore-arc and DSDP ocean drilling data, this paper studies the development and evolution characteristics of the structure and strata in the Cenozoic Mariana fore-arc sedimentary basin. The Cenozoic strata are divided into six seismic sequences, with the possible era of each seismic sequence discerned, and the relationship between fault development and earthquakes analyzed. The episodic activity of the volcanic chain of the Mariana island arc is thought to control the tectonic and stratigraphic development pattern of the Cenozoic sedimentary basin in the fore-arc. Between 16°N–19°N and 146°E–151°E, the maximum thickness of the sedimentary center of the Cenozoic fore-arc sedimentary basin in Mariana is about 2360 m. Normal faults are developed in the area and some broke to the seabed, indicating that the Mariana island arc is still in the post-arc expansion stage. The application of multi-channel seismic sections in structural and stratigraphic evolution study is an important means to elucidating the Mariana subduction mechanism.

摘要:The northern margin of the North China Craton (NCC) contains widespread Permian magmatic rocks, but the origin of these rocks remains controversial. This uncertainty hampers us from better understanding of tectonic framework and evolution of the eastern Paleo-Asian Ocean, particularly with respect to its final-stage subduction and closure time. To address these questions, this study presents petrological, zircon U-Pb geochronological, whole-rock geochemical and in situ zircon Hf isotopic data for these Permian mafic intrusions in the northern margin of the NCC. Precise zircon U-Pb dating results indicate that these mafic intrusions were emplaced in the Middle Permian (ca. 260 Ma). Geochemically, the studied mafic intrusions have high MgO and transition metals element contents, with high Mg# values, indicating a mantle origin. These mafic intrusions are characterized by enrichments in large ion lithophile elements (LILEs; e.g., Rb, Ba, and K) and light rare earth elements (LREEs), and depletions in high field strength elements (HFSEs; e.g., Nb, Ta, and Ti) and heavy rare earth elements (HREEs), indicating that they were formed in a subduction-related setting. These geochemical features, together with zircon εHf(t) values (?1.1 to +11.2), indicate that their parental magmas were derived from partial melting of heterogeneous mantle wedge metasomatized by subduction-related fluids, with the contributions of slab sediments. The studied mafic intrusions also show wide range of major and trace elements contents, and variable Mg# values, Eu and Sr anomalies, suggesting that their parental magmas had undergone variable degrees of fractional crystallization. Together with the E–W trending Permian continental arc along the northern margin of the NCC, we confirm that the generation of the Middle Permian mafic intrusions was related to southward subduction of the Paleo-Asian oceanic lithosphere beneath the NCC and the Paleo-Asian Ocean had not closed prior to the Middle Permian.

摘要:Shallow groundwater collected in Chaozhou, Huizhou, and Guangzhou allowed testing of concentrations and the isotope ratios of noble gases. Based on the calculated noble gas temperature (NGT) and the ratio of noble gas isotopes, the recharge temperature, recharge source, and residence time of groundwater can be calculated. In addition, the contribution of noble gas components from different sources to the sample components can be assessed. In the Huizhou area, according to the 1/Xe vs. Ne/Xe and NGT data, the shallow sandstone-confined water samples in the Shiba area and the unconfined water samples of the Huangshadong are in different temperature ranges, indicating that they have different recharge sources, both in time or space. The He components in the samples are calculated to obtain the content of radiogenic 4He in the crust and to simulate the groundwater ages. The noble gas isotope ratios show the addition of mantle components into the basalt aquifers and sandstone aquifers in Chaozhou and Huizhou. Except for atmospheric and crustal sources, there is a certain proportion of mantle-derived components in the shallow underground cold water in Huizhou and Chaozhou. The noble gases in the Chaozhou groundwater have an obvious mantle signature, allowing speculation that there is a deep fluid carrying mantle characteristics. This upwelling of mantle-derived material might be caused by the India-Eurasia collision or that between the Philippine Sea Plate and the Eurasian Plate.

摘要:Garnet megacryst with a multiphase inclusion from intraplate alkali basalts of the Shavaryn Tsaram (Tariat, Mongolia) was the object of the study. This unusual aggregate consists of porous glass, Ti-rich biotite, orthopyroxene, spinel, clinopyroxene, olivine, and ilmenite. WinTWQ 2.32 thermodynamic simulation of this system revealed a few intervals of equilibrium. Pressure and temperature adjustment reflected in the paragenetic minerals of the melt pocket. The capture of already crystallised garnet megacryst was at P = 0.8–1 GPa and T = 1120–1160°C. Mineral crystallisation inside the melt pocket, accompanied by external inputs, occurred at P = 0.75–0.95 GPa; T = 790–1120°C. Symplectite assemblage formed in the garnet megacryst due to decomposition at (P = 0.55–0.7 GPa; T = 850–930°C). The study of the oxygen isotope content in primary garnet and biotite of the melt pocket showed that the δ18OVSMOW values are the same and correspond to that of typical mantle xenoliths. However, the chemical and microcomponent composition of the melt pocket minerals reveals a material that differs from basalts and peridotites. Thus, it has been revealed that the multiphase inclusion in the garnet megacryst formed not only on account of the garnet's substance, but also due to the entrapped material of the Earth's interior.

摘要:Tourmaline geochemical and boron (B) isotopic compositions in two-mica granites (TMG), tourmaline-bearing leucogranites (Tou-LG), tourmalites and metapelites from the Gyirong–Malashan areas of the Himalayan orogen provide evidence for country rock assimilation during the intrusion of Himalayan leucogranite. The schorls in Gyirong leucogranitic plutons show low contents of MgO (0.238%–1.160%) and δ11B values (?12.1‰–?11.2‰), while dravites gathered in the contact zone between the leucogranitic veins and metapelites show high contents of MgO (4.815%–6.755%) and δ11B values (?10.7‰–?9.3‰). This geochemical and isotopic variation of tourmalines can also be identified in the Malashan gneiss dome. As a result, three types of tourmaline were identified in the Himalayan orogen: (1) Tou-I in the TMG and Tou-LG, which is the most common tourmaline type of schorl; (2) Tou-II (dravite and high-Mg schorl) in the Tou-LG and tourmalite at the margins of the leucogranite; and (3) Tou-III (mainly dravite, with minor high-Mg schorl) in metapelites of the High Himalayan Crystalline Sequence. The lenses and veins of Tou-LG may have experienced metasomatism and assimilation as a result of interaction with the High Himalayan Crystalline Sequence metasedimentary country rocks, which can be traced by the geochemical and isotopic characteristics of the tourmaline therein.

摘要:The Aqishan lead-zinc deposit, located in the Jueluotag metallogenic belt of eastern Tianshan, Xinjiang, Northwest China, has a stratiform occurrence in the marine volcanic tuff of the Yamansu Formation. The ore body has a typical double-layer structure, having a stratified, stratoid, lenticular upper part and a veined, stockwork-like lower part. The occurrence of the upper orebody is consistent with that of the volcanic tuff wall rock. The ore minerals are mainly chalcopyrite, pyrite, sphalerite, galena and magnetite, the altered minerals mainly being silicified, such as sericite, chlorite, epidote, garnet. The garnetized skarn, being stratiform and stratoid, is closely related to the upper part of the orebody. Geological observations show that the limestone in the ore-bearing Yamansu Formation is not marbleized and skarnized. Spatially, it is associated