China is not only a major consumer of cobalt resources but also a big importer of cobalt resources. Influenced by the new energy electric vehicle industry, cobalt ore resources have attracted more and more attention in recent years. In order to scientifically evaluate the potential of cobalt resources, guide the deployment of prospecting and exploration, and improve the guarantee capacity of cobalt resources in China, we carried out cobalt resource potential evaluation of cobalt resources in 9 key provinces (regions) from 2019 to 2021. Based on the perspective of the distribution and geological characteristics of cobalt deposits, the types of cobalt deposits predicted for prospecting in China are determined, including: weathering type, chemical deposit type, sandstone type and submarine hydrothermal-sedimentary type, all of which related to the sedimentary geological processes; marine and continental volcanic rock type that related to the volcanic geological processes; magmatic type, skarn type (contact metasomatic type), hydrothermal vein type and porphyry type, all of which associated with intrusive magmatism; sedimentary metamorphic type and a small number of metamorphic core complexes type that related to the metamorphism. And the metallogenic geological bodies related to various types of cobalt deposits are also sorted out and summarized. By analyzing the geological characteristics and spatio-temporal distribution of cobalt deposits in China, and synthesizing prediction elements such as geological, geophysical, geochemical, and remote sensing information, a prospecting prediction model was established, prospecting potential areas were delineated, and resource reserves were estimated. The results show that the cobalt deposits in China include six main prospecting prediction types: weathering crust nickel-cobalt deposit, hydrothermal-sedimentary copper-cobalt deposit, marine volcanic rock copper-cobalt deposit, marine volcanic rock massive sulfide copper-zinc cobalt deposit, magmatic copper-nickel cobalt deposit and hydrothermal veined cobalt deposit; 416 cobalt ores were delineated,  64 prospecting potential areas were delineated, 99 prospecting targets were optimized, and further exploration suggestions were put forward. A total of 453 000 t of cobalt resources have been identified in 9 key provinces (regions), and the estimated cobalt resources are about 420 million t.

Qinghai Province is located in the Northeastern Qinghai-Tibet Plateau, where the Qinling-Qilian-Kunlun and the northern Qiangtang-Sanjiang orogens are amalgamated. It has experienced the formation and development of the basement, spreading, subduction, closure and collision of the Proto-Paleo-Neo Tethys Ocean, and plateau uplift process. In the long-term geological tectonic evolution, different metallogenic processes occur and are accompanied by a series of ore deposits in a specific time and space. Based on the latest mineral exploration achievements obtained since the implementation of the “Qinghai 358 Geological Exploration Engineering” and “Strategic Action of Prospecting Breakthrough”, 137 kinds of minerals, 895 deposits and 4 597 ore (chemical) points have been analyzed. A systematic summary and study of the tectonic environment, metallogenic geological conditions, metallogenic characteristics, metallogenic processes, genetic types, metallogenic ages and metallogenic regularities, using the metallogenic series theory proposed by Chen Yuchuan et al., 14 metallogenic series groups, 46 metallogenic series, 76 metallogenic sub-series and 131 ore deposit types of major deposits in Qinghai Province were divided. Finally, 11 metallogenic series groups, 25 metallogenic series, 44 metallogenic sub-series and 63 typical ore deposit types with the most prospecting prospects are proposed, and a brief summary and analysis are made according to metallogenic zones.

 Qaidam basin is the main salt storage ore belt in China. At present, there have discovered 12 kinds of minerals with proven reserves and resources, among which the reserves of potassium chloride, magnesium chloride and lithium chloride rank first in China. At the same time, many deposits/ore bodies in new regions, new horizons, new types and new depths have been discovered, showing that Qaidam basin has great prospecting potential. Based on the division of national metallogenic units, using the latest research results, on the basis of Qaidam basin in the Cenozoic geological tectonic environment, highlighting the principle of salt minerals, this paper comprehensively analyzes the lithofacies, paleoclimate, hydrological conditions, salt metallogenic laws and metallogenic characteristics of salt bearing minerals, and systematically divides the salt metallogenic units of Qaidam basin. In this paper, it is proposed that the Grade Ⅰ metallogenic domain belongs to the Qin-Qi-Kun metallogenic domain, the Grade Ⅱ metallogenic province belongs to the Kunlun metallogenic province, and the Grade Ⅲ metallogenic belt is the Li-B-K-Na-Mg-salt-oil-gas-glauber’s salt-natural alkali metallogenic belt in the Qaidam basin; It is further divided into five Grade Ⅳ metallogenic subzones: The boron-lithium-potassium mineralization subzone in the northern margin of Qaidam basin, the central potassium-halite-magnesium-lithium-celestite-mirabilite metallogenic subzone, the boron-potassium-halite-mirabilite mineralization subzone in the north of Kunlun, the Chaerhan potassium-halite-magnesium-lithium-boron-trona metallogenic subzone, and the Delingha halite-trona metallogenic subzone; and 21 Grade V ore concentration areas.

The East Kunlun Metallogenic Belt (EKMB) is an important Au-Cu-Co-Ni-Fe-Pb-Zn and other polymetallic metallogenic belts in China. The discovery of the Xiarihamu super-large Ni deposit in the summer of 2011 made East Kunlun become an important Cu-Ni resource base in China. After years of exploration, great breakthroughs have been made in the prospecting of Cu-Ni deposits in the EKMB, and a number of mafic-ultramafic complexes with great prospecting potential have been discovered successively, such as Shitoukengde, Akechukesai, Langmuri and Gayahe intrusions. Based on the researches in recent years, the metallogenic regularity and characteristics of the magmatic Cu-Ni sulfide deposits in the EKMB are preliminarily summarized, and the prospecting target for the next step is pointed out. Main understandings are as follows: At least four stages of Cu-Ni-Co-(PGE) metallogenesis with different intensities occurred in the EKMB, i.e., Cambrian-Ordovician (535-445 Ma), Silurian-Devonian (440-394 Ma), Permian-Early Triassic (271-239 Ma) and Late Triassic (233-208 Ma), among which the Silurian-Devonian has the largest number of intrusions and the highest mineralization rate, and produces the largest number and scale of ore deposits, while other stages have less number of intrusions, smaller scale and weaker mineralization. Different from other ore-forming plutons scattered throughout the EKMB, the Silurian-Devonian intrusions are strictly distributed in the north of the Central Kunlun fault, and most of them occur in the Central Kunlun belt with significant clustering. They have significant metallogenic specialization with the most important ore-bearing rocks belonging to ultramafic rocks enriching in chrysolite and orthopyroxene. The primary magma is derived from the large proportion of partial melting of the asthenospheric mantle, and crustal contamination is one of the most important key factors of sulfide saturation. The Silurian-Devonian intrusions have the greatest prospecting potential, mainly distributed in the Central Kunlun belt, which is the main prospecting target and area for future prospecting and exploration. The intrusions of other stages have less prospecting potential, but the Cu-(PGE) ore-bearing of Cambrian-Ordovician intrusions still need to be further evaluated.

Hongshuihe iron deposit in the Eastern Kunlun orogenic belt, Qinghai Province, is a middle-sized one in which iron formations are localized within the phyllite of the Langyashan Formation. The ore types are mainly massive magnetite quartzite type, and minor banded type, which was generally considered as sedimentary metamorphic iron deposit by predecessors. Based on previous researches, this paper presents new data from major, rare earth and trace elements as well as Fe isotope analyses for massive iron ores in the iron formations of the Hongshuihe iron deposit. New Fe isotope results yield variableδ56FeIRMM-014values mostly ranging from 0.97‰to1.97‰, with one exception, showing similar Fe isotope compositions with typical Neoproterozoic iron formations of the world. The results of major, rare earth and trace elements show that these ores have high SiO₂+Fe₂O₃ contents (78.56%-98.06%)and very low Al/(Al+Fe+Mn) ratios of 0.00-0.06, indicating that they are typical chemical sedimentary rocks. The total rare-earth-element contents (∑REE) vary from 16.49×10^-6 to 80.89×10^-6, with no obvious Ce abnormally, and light-rare-earth-element are slightly depleted, which shows a similar characteristic to the Neoproterozoic iron-bearing structures. Based on the comprehensive comparison of Fe isotope compositions, depositional ages and geochemical characteristics of iron formations in the Hongshuihe iron deposit, we can conclude that there was a passive continental margin tectonic environment of the Qaidam-East Kunbei block in the Neoproterozoic during iron formation, and iron and other ore-forming materials were predominantly derived from marine hydrothermal fluids. The marine hydrothermal fluids rich in Fe²+ upwelled and gradually evolved into low-temperature hydrothermal fluids which then mixed with oxygen-bearing surface seawater in a sub-oxidized condition. Finally, Fe²+ was partially oxidized and formed ferric hydroxides, which subsequently deposited on the continental slope and eventually formed iron formations. The genetic type of the Hongshuihe iron deposit can be classified as the Neoproterozoic Rapitan-type iron formations.

[WTHZ]Key words:[WTBZ] 

Halongxiuma molybdenum polymetallic deposit is the only medium-sized porphyry deposit in the eastern part of the East Kunlun metallogenic belt. Based on the detailed study of fluid inclusions and H-O-S isotopes, this paper finds out the nature of ore-forming fluids and the source of ore-forming materials, and constructs the metallogenic model of this deposit. Petrography and microthermometry of fluid inclusions show that two types of inclusions, namely gas-liquid two-phase and CO₂ containing three-phase, are developed in Halongxiuma deposit. The ore-forming fluids are characterized by medium to high temperature (concentrated in 280-340 ℃), high salinity (concentrated in 6.00%-18.00%) and medium density (concentrated in 0.64-0.92 g/cm³), and the metallogenic depth is 2.4-4.1 km, suggesting that the deposit was formed in a meso-epithermal environment. The results of H-O isotope show that the ore-forming fluids are derived from the mixing of magmatic and atmospheric water, and the main component is magmatic water; The results of S isotope show that the ore-forming materials mainly come from the deep magma. Combined with the regional tectonic evolution, it is considered that the metallogenic model of Halongxiuma deposit is as follows: Firstly, intense crust-mantle mixing occurred in East Kunlun area during the Late Indosinian, producing a mixed magma rich in ore-forming elements; Then the ore-bearing fluids boiled during the ascent of the mixed magma and cooled down due to the addition of [JP2]atmospheric water, resulting in the changes in the physical and chemical conditions of mineralization, and promoting the precipitation of metallogenic materials.

  Aritekshan Cu-Mo deposit is a newly discovered concealed porphyry deposit, located in the central-north part of the northern Qaidam basin. The orebodies occurred in the contact area between the Late Hercynian-Indosinian granodiorite (porphyry) and Paleoproterozoic Dakendaban Group. In order to explore the characteristics of ore-forming fluids, the ore-forming mechanism and genesis of the deposit, this paper systematically studied the field geological characteristics, fluid inclusions and stable isotope composition of the deposit. According to the relationship between different types of ore veins, the hydrothermal metallogenic stages can be divided into the early mineralization quartz stage, molybdenum-polymetallic sulfide-quartz stage and late mineralization quartz-calcite stage. The fluid inclusions are mainly Type Ⅰ (liquid-rich L+V two-phase aqueous inclusions), Type Ⅱ (gas-rich L+V two-phase aqueous inclusions) and Type Ⅲ (three-phase aqueous solution inclusions containing daughter minerals). The results of microthermometry and inclusion Raman spectrum analysis show that the ore-forming fluid system is NaCl-H₂O system with medium-high temperature, medium-low salinity, and medium-high density. In the late stage of mineralization, the properties of the fluids changed to low temperature, low salinity and high density fluid, with the deposit formation depth of 0.40-4.00 km. The values of D_V-SMOW and δ¹⁸ O_H2O range from -92.9‰ to -78.4‰ and -7.4‰ to 2.0‰ respectively, indicating that the ore-forming fluids are mainly mixed fluids. With the evolution of ore-forming fluids, the continuous mixing of meteoric water affects mineralization. Theδ³⁴S of metal sulfide in the ore ranges from 9.4‰ to 11.7‰, with an average value of 10.2‰, showing obvious characteristics of strata sulfur, which is caused by the interaction between magmatic hydrothermal fluid and surrounding rock strata. It is believed that  Aritekshan Cu-Mo deposit is a skarn-porphyry type deposit, which was formed in the subduction and collision during Late Hercynian-Indosinian, which is consistent with the diagenetic age of granodiorite. The strong immiscibility of mixed ore-forming fluids is the main mechanism of the formation of porphyry Cu-Mo deposit.

 The basic geological research of Akchukesai area in the western Segment of the East Kunlun orogenic belt is weak. The granite gneiss in this area was designated as the Jinshuikou Group by predecessors. In field work, it was found that the Jinshuikou Group gneiss should be a granite gneiss intrusion. In order to determine the geochronology and petrogenesis of the intrusion， the rock geochemistry, zircon U-Pb geochronology and Hf isotope studies were carried out in this paper. The results show that: the lithology of the sample is gneissic biotite monzogranite, major element data show that the SiO₂ content is 74.44%-76.36%, Na₂O and K₂O contents are respectively 0.06%-0.07% and 3.89%-4.35%, Al₂O₃ content is 9.76%-10.95%, A/CNK is 0.92-1.09，TiO₂ and MnO contents are respectively 0.32%-0.38% and 0.10%-0.13%；CaO content is 2.70%-3.46%，Mg^# is 25.42-29.69；The rare earth elements of the samples are higher, ΣREE is 200.04×10^-6-215.30×10^-6, LREE/HREE is 6.94-7.88. Trace elements show the characteristics of enriched in Rb, U, Th, K and Nb, Ta, P, Ti, Sr showed“V”type depleted. The age of formation is Early Neoproterozoic ((966±3)Ma，MSWD=4.1), zricon in situε_Hf(t)=-3.38-3.14, Hf isotope two-stage model ages T_DM2 range from 2 033-1 625 Ma. Petrogeochemical and Hf isotopic results show that the gneissic biotite monzogranite is peraluminous-weak peraluminous high-K calc-alkaline I-Type granite. The magma source area should be dominated by new basaltic crust, with the addition of Paleoproterozoic silical-aluminum crust, which may be the partial melting of plagioamphibole and gneiss of  Paleoproterozoic Jinshuikou Group. The petrogeochemical characteristics show that the samples were formed under the tectonic background of subduction to collision transformation in the Early Neoproterozoic. Based on the comprehensive analysis of regional tectonic background, it is concluded that Early Neoproterozoic magmatism and tectonic activity are prevalent in the East Kunlun region, which responds to the global Rodinia supercontinent convergence event. The samples studied in this study are the concrete manifestation of the collision formation of Rodinia supercontinent convergence in the western segment of East Kunlun, this indicates that the region was transitioning from subduction to collision orogenic stage at  about 966 Ma.

A set of epimetamorphic marine volcano-sedimentary rock series developed in Tuolugou cobalt (gold) mining area, Qinghai Province, of which the formation ages and tectonic attributes are controversial. In this paper, zircon LA-ICP-MS dating, Lu-Hf isotopic and geochemical analysis were carried out on the phyllites from Tuolugou deposit, and their protolith depositional ages, sediment provenance and tectonic affinity of the basement were discussed. The chronological results show that the youngest age group of detrital zircons is 433-412 Ma with weighted average age of (422.8±6.8)Ma. Combined with the data of regional tectonic magmatic events, the upper limit of the protolithic depositional age is the Late Silurian. Theε_Hf(t) values of zircons in age group of 433-412 Ma range from －2.02 to 5.47, with an average of 1.80, indicating that the parent rocks of this zircon group are mainly new crustal materials. The T_DM1 age ranges from 1 124 to 829 Ma, indicating that the zircons originated from the crust mantle interaction during the convergence of the Rodinia supercontinent in the Grenvillian period. The petrogeochemical results show that the protolites of the Tuolugou phyllites may be a set of mud-sandy sedimentary rocks, and the depositional environment is a stable passive continental margin. It is consistent with the result of regional tectonic evolution which is: The subduction of the middle Kunlun Ocean ended around 430 Ma, and the whole east Kunlun area began to enter the intraplate extension setting, while the southern part of the south Kunlun block entered the passive continental margin in the Late Silurian. The comprehensive analysis of the U-Pb age spectrum of detrital zircons shows that the original properties of detrital zircons during the Archean is not clear, and the basement of the south Kunlun in the Mesoproterozoic has obvious affinity with the South China craton. Since the Grenvillian orogeny formed the United Continent of Cathaysia-Yangzi-Kunlun-Qaidam-Qilian, the Kunlun block may have been separated from the United Continent during the Pan-African period (about 650-550 Ma)

The Huangyanggou diorite porphyrite pluton intruded in the limestone of the Late Jurassic Hongqilafu Formation, which is located in Tianshuihai-Kalakunlun Terrane. In order to determine its formation age and reveal the petrogenesis and tectonic background, LA-ICP-MS zircon U-Pb geochronology and whole-rock geochemical analysis of Huangyanggou diorite porphyry were carried out.The zircon U-Pb age of the pluton is 159.9 Ma, which is formed in a post-collisional extensional environment. The magma source is characterized by mantle source, with the assimilation and mixing of crustal materials, which indicated the formation conditions were low pressure, strong oxidation environment and experienced intermediate differentiation. The pluton is characterized by low silicon (w(SiO₂)=56.11%-57.36%), high calcium (w(CaO)=4.29%-6.59%), and alkali-rich (w(Na₂O+K₂O)=6.00%-7.96%), and belongs to quasi-aluminous (A/NCK=0.79-0.95) rocks. It is also enriched in large ionic lithophile elements (K, Rb, Ba, Th, U) and depleted high field strength (Nb, Ta, Zr, Hf) elements, with a weak Eu negative anomaly (δEu mean 0.97). Through the comparative study of the regional magmatic activities, the Huangyanggou pluton has a strong affinity with the Pa’a I-type granite in the Geji area of the Bangonghu-Nujiang suture zone, and is consistent with the formation ages of the magmatic rocks exposed in this suture zone. It indicates that the Huangyanggou diorite porphyrite in the south of the Tianshuihai terrane is a magmatic response to the southward subduction of the Meso-Neo-Tethys Ocean in the northern Bangonghu-Nujiang suture zone.

 The Petrogenesis of the Awengcuo-Yanhu magmatic arc in Lhasa terrane is the key to solve the subduction polarity and time of the Bangong-Nujiang Tethy Ocean. In this paper, the monzonitic granite in the north Awengcuo was selected for petrography, geochemistry, zircon U-Pb geochronology and Hf isotopic studies. The zircon ²⁰⁶Pb/²³⁸U weighted mean age of the monzonitic granite is (107.0±0.5) Ma, MSWD＝2.6, belonging to the Late Early Cretaceous. The samples are a series of high-silicon and potassium-rich high-potassium calc-alkaline rocks with A/CNK values ranging from 1.006 to 1.019, belonging to weak peraluminum. The trace elements are enriched in large ion lithophile elements Rb, K, U, Th and LREE, depleted in high field strength elements such as Nb, Ta, P, Ti, with moderate to weak negative Eu anomalies (δEu = 0.55-0.78), belonging to a weakly peralumious undifferentiated I-type granite. The monzonitic granite yields the zircons ε_Hf(t) values of 3.7-6.3 with a mean of 5.0, except for one characteristic value of 11.1, and the model ages (t_DM2) range from 928 Ma to 765 Ma. Based on integrated isotopic and geochemical data, the north Awengcuo pluton is probably formed by the heterogeneous mixing of felsic magma and mafic magma generated by the melting of the juvenile crust, with the participation of a small amount of mantle-derived materials. Combined with Hf isotope analysis of magmatic rocks in the north-central Lhasa terrane, the Awengcuo-Yanhu magmatic arc was formed under the tectonic regime of the backward subduction of the Bangong-Nujiang Tethy Ocean, and the formation age of the pluton from the north Awengcuo (107-104 Ma) represents the time for the transformation from the end of slab break-off to the collision environment.

 The genetic mechanism of Chang’an gold deposit in the southern section of  Ailaoshan metallogenic belt in Southwest China remains to be restricted. To understand the source of ore-forming materials and fluids, and to illustrate its genetic type of deposit could provide a basis for the mine prospecting and reserve increasing. In this paper, the source and evolution of metallogenic materials and fluids in Chang’an gold deposit are studied based on detailed geological features, ore H-O-S-Pb isotope analysis and temperature measurement of fluid inclusions, and then the genesis of the deposit is restricted and the metallogenic model is established. The results show that the near-SN-trending F₆ considered by predecessors is not a fault, but a cryptoexplosive breccia tube, which is the main ore hosting structure of Chang’an gold deposit. In the main metallogenic stage, the freezing point temperature of the inclusions is mostly -2.9--0.7 ℃, the corresponding salinity (w (NaCl)) is 1.22%-4.79%, and the homogenization temperature is 162-226 ℃, which belongs to the low temperature and low salinity fluid system. The δ¹⁸O_H2O of quartz in the main metallogenic stage is between 4.4‰ and 5.2‰, and the δD is -93.9‰--85.9‰, which falls between the evolution line of magmatic water and atmospheric water, indicating that the ore-forming fluid is a mixture of magmatic fluid and atmospheric water. The averageδ³⁴S of pyrite in Chang’an gold deposit is 2.1‰ (n = 32), most of which are between 0.0 and 3.6‰, with obvious characteristics of magmatic sulfur suggesting that S comes from magmatic rocks. The lead isotopic composition of pyrite has obvious duality, reflecting the dual contribution of magmatic and upper crustal surrounding rocks. Therefore, it is considered that the ore-forming materials and fluids are mainly derived from magma, and the later atmospheric water and surrounding rocks also contribute to the metallogenic fluids. Chang’an gold deposit, which has similar characteristics to low-sulfidation epithermal gold deposits, is dominated by cryptoexplosive breccias, although its surrounding rocks are not traditional volcanic rocks.

Sipingshan gold deposit is located in the Wandashan epicontinental accretional terrane in eastern Heilongjiang, China. The ore bodies are mainly hosted in the Lower Cretaceous Sipingshan Formation, showing obvious two-stage mineralization. To further determine the mineralization and genesis of the deposit, this study analyzes its metallogenic geological characteristics, metallogenic chronology and source of metallogenic materials. The samples from the ore-related granite porphyry have relatively high SiO₂ (70.07%-72.93%) and （K₂O+Na₂O）(7.17%-8.42%), which belong to A-type granite. The ore-bearing siliceous rocks are characterized by Al/(Fe+Al+Mn)<0.32, Fe/Ti>20, (Fe+Mn)/Ti >20, Fe₂O₃ (0.18%-1.79%), FeO(0.17%-0.96%), MnO (0.03%-0.12%), TiO₂ (0.03%-0.04%), Al₂O₃ (0.30%-2.79%), (K₂O+Na₂O)(0.07%-1.76%), indicating that Sipingshan gold deposit is formed in a hydrothermal depositional environment related to magmatic activity in the tectonic setting of active continental margins. The granite porphyry is identified as the parent rock of Sipingshan gold deposit, with a U-Pb zircon age of (113.5±0.7) Ma. The H(δD=-182.3‰--84.0‰),O(δ¹⁸O_V-SMOW=6.5‰-14.3‰), and S(δ³⁴S=-12.4‰-29.7‰) isotopic results indicate that the ore-forming fluid is mainly atmospheric precipitation, and the ore-forming materials have stratigraphically dominated multi-source features. To sum up, Sipingshan gold deposit is a hydrothermal sedimentary deposit formed in the Late Yanshanian active continental margin tectonic background. The continuous subduction of the Pacific plate caused large-scale delamination, resulting in a transition from extrusion to extension. This granite porphyry magma formed at this period migrated to the shallow crustal magma chamber to heat the overlying stratum, and formed a temperature and pressure gradient zone in the shallow crust, which prompted the atmospheric precipitation on the surface to enter the stratum along the fissures to form a fluid circulation system, and continuously extract Au elements in the formation to form ore-bearing fluids. In the early stage,when the pressure drived the ore-bearing fluids to be ejected from the surface, it encountered the surface water and cooled rapidly, and the ore-forming materials precipitated rapidly, forming the  layered ore-bearing siliceous rocks and siliceous cemented conglomerates, which formed layered orebodies by metasomatism of the underlying rhyolite porphyry. This process was weakened with the thermal power provided by the magma chamber dying down. In the later stage, the ore-bearing fluids stayed in the fissure channels or penetrated into the fissures of the early consolidated ore-bearing layer, then precipitated to form vein-like and reticulated-vein-like ore bodies.

Hongqiling magmatic Cu-Ni sulfide deposit is located in the southeastern margin of the Central Asian orogenic belt (CAOB). In this paper, the multi-degree vertical derivative and 2.5-D interactive inversion technique are used to predict the mineralization of the hidden orebodies in the deep (500-1 000 m) Cu-Ni deposit, and to study the ore-bearing properties of the mafic-ultramafic rocks (such as #1, #3 and new #3 plutons). The results show that the high-precision gravity anomaly can effectively determine the spatial distribution of deep hidden orebodies by carrying out data processing on the upper edge of different heights and the vertical first-order derivative, and the 2.5-D interactive inversion technique can be used to detect the weak anomaly caused by deep orebodies. It is speculated that there are 5 blind vein-shaped orebodies in the #3 pluton in the study area with a burial depth of 700-1 100 m. After drilling verification, 32 259 t of Ni ore was successfully discovered (the average grade of ore is 0.36%), of which No. 2 ore body is the thickest ore body, the ore penetration depth is 700-1 100 m, the average Ni ore grade is 0.39%, and the reserves are up to 27 433 t.

Based on the comprehensive research on field geology, petrography, geochronology and geochemistry of the Early Cretaceous intermediate-acidic magmatic rocks of Xiaoxinancha copper (gold) deposit in Yanbian, Jilin Province, the isotopic ages are determined to be(101.69±0.61) Ma (quartz diorite), (101.14±0.58) Ma (tonalite), (100.82±0.62) Ma (granodiorite) and (100.20±1.10) Ma (diorite porphyrite). The magmatism occurred at the end of the Early Cretaceous (102-100 Ma), which is the product of the same tectonic evolution process. The diorite porphyrite has the geochemical characteristics of typical adakitic rocks, with w(SiO₂)=61.419%-62.153%， w(Al₂O₃)=16.872%-17.329%,w(MgO)=2.339%-2.643%,w(Na₂O)=5.749%-6.623%, w(K₂O))=1.483%-1.786%, w(Sr)=(691-888)×10^-6,w(Yb)=(0.71-0.83)×10^-6,Sr/Y=87.4-120.0.The enrichment of LREE is formed by the in-situ intrusion of adakitic magma generated by partial melting of the subducted oceanic slab. The adakitic magma mixed with the acidic magma produced by the remelting of the lower crust during the upwelling process to form the enriched mantle source magma which was upwardly emplaced, and formed the calc-alkaline granitic complexes such as quartz diorite, tonalite and granodiorite. The magmatic hydrothermal fluid is mixed with atmospheric precipitation during the ascent along the regional faults, extracted the metallogenic materials in the surrounding rocks, and formed the metallogenic hydrothermal fluid rich in copper (gold) components, and unloaded and precipitated at a suitable location to form vein-type copper (gold) mineralization. Yanbian area was located in the continental margin environment where the paleo Pacific plate subducted to the Eurasian plate in the Late Mesozoic. The subduction of the paleo-Pacific plate was the direct driving force for the formation of Early Cretaceous quartz diorite, tonalite, granodiorite, diorite porphyrite (dikes)and hydrothermal vein-type copper (gold) mineralization in Xiaoxinancha deposit.

 The paleo-Pacific tectonic system controls the formation and evolution of the East Asian continental margin, but there is still controversy over the onset of the subduction of the paleo-Pacific plate and its detailed evolution process.  Shiren Village in Helong Lity is located in south Jilin Province, in the eastern part of the northern margin of the North China plate, which is a favorable area to study the evolution of the paleo-Pacific Ocean. This paper presents a synthesis study of zircon U-Pb geochronology, geochemistry and Hf isotopes on the granodiorites. The studied rocks yield an average zircon LA-ICP-MS U-Pb age of (173±1) Ma, suggesting a Middle Jurassic magmatic event. The rocks are characterizd by high Mg^#(65.23%-65.92%), abnormally high w (Sr)（(1 657-2 467)×10^-6）, and low w (Y)（(7.50-7.98)×10^-6） and w(HREE), very similar to the low Si adakite defined by Martin et al.(2005), reflecting that the initial magma is derived from the mantle wedge metasomatized by plate melting. The significance lies in the existence of very hot subduction in this area around 173 Ma, which may be caused by an oblique subduction or oceanic ridge subduction, and also means that the subduction direction of the paleo-Pacific plate towards Eurasia deflected or the subduction mode changed in the Early Middle Jurassic. However, the studied rocks are different from the typical low Si adakites, while their w (SiO₂) values (61.13%-62.31%)are significantly greater than 56%.The traces of magmatic mixing were observed in both the field and under the microscope, reflecting that the magma experienced the evolution process of magmatic mixing in an open system during the emplacement process.

The Qinhuangdao area of eastern Hebei is located in the eastern part of the North China plate, where Mesozoic volcanic rocks are widely developed. In order to further study the tectonic setting and movement mechanism of Mesozoic magmatism in this area, the LA-ICP-MS zircon U-Pb geochronology, Hf isotopic compositions, major and trace elements of the rhyolitic crystal tuffs in Rugezhuang were analyzed. The results show that zircons have a clear oscillatory zoning, and the Th/U value of zircons is 0.37-0.83, indicating they are magmatic zircons with the weighted average age of (113±1) Ma. The rocks are characterized by high silicon (75.95%), high alkali (8.47%) and low calcium (0.39%). HFSE (Th, U, Ce, Nd, Zr, Hf) are enriched and LILE (Ba, Sr, P, Ti) are depleted in analyzed samples. The REE distribution patterns dip slightly to the right, andδEu (0.02-0.30) is obviously negative anomaly, suggesting that a large amount of plagioclase was crystallized. During the evolution of the magma, along with the crystallization of apatite, ilmenite and other minerals, the value of Nb/Ta is close to that of the continental crust, suggesting that analyzed rocks have the characteristics of crustal rocks. Zircon Hf isotopic compositions and temporal variations show that the magma source of the rocks is the product of partial melting of the ancient lower crust of the North China plate in the Late Early Proterozoic to Middle Mesoproterozoic due to the heating from mantle-derived magma. The results show that the rhyolitic crystal tuffs in Rugezhuang are the products of magmatic activities in the Early Cretaceous, and was formed in the intraplate extensional environment driven by the subduction and roll-back of the Paleo-Pacific plate.

In order to accelerate the exploration and development process of deep tight sandstone gas in the southern Songliao basin, the formation mechanism of tight sandstone reservoir and the main controlling factors of reservoir formation are studied. At present, the discovered deep tight gas can be divided into three types: Stable thick sandstone, sandstone-mudstone interbedding, and muddy wrapped sandstone according to the petrological characteristics of tight sandstone. The physical properties of the reservoir are generally poor, the main porosity is below 6%, and the main permeability is less than 0.10×10^-3 μm², which belong to ultra-low porosity and ultra-low permeability reservoir. Based on the mineral composition and microscopic characteristics of typical tight reservoirs, it is found that the formation of effective reservoirs of tight sandstone is mainly controlled by three factors: First, chlorite enclaves are developed in the early diagenetic stage, which effectively inhibit the occurrence of intergranular calcareous cementation and siliceous cementation during the middle and late diagenesis, and protect the original residual intergranular pores; Second, secondary pores are formed by the dissolution of volcanic rock debris; Third, hydrocarbon generation pressurization produces a large number of micro fractures, which improves the seepage characteristics of the reservoir. The controlling factors of tight sandstone gas reservoir formation  are summarized as followings, the sufficient gas source, the sandbody controlled by slope paleo-valley and fault, the reservoir controlled by secondary dissolution and microfracture, the enrichment controlled by fault activity and stable cap rock.

 In order to conduct a systematic study of thick dark mudstone and coal seams in the deep Late Paleozoic strata at the eastern foot of Taihang Mountains, Henan Province, taking the Late Paleozoic strata as the research object and using methods of sedimentology and sequence stratigraphy, the high resolution stratigraphic correlation and sedimentary facies division of the Upper Paleozoic Taiyuan Formation, Shanxi Formation and Xiashihezi Formation in the study area were carried out. A total of 5 rock types, 16 lithofacies types, 5 sedimentary facies and 10 sedimentary subfacies are identified. Three sequence boundaries and two key system tract boundaries were further identified, and 10 third-order sequences and corresponding system tracts were divided. Therefore, the sequence stratigraphic framework of coal measures strata in this area were established, the lithofacies paleogeographic characteristics in the isochronous stratigraphic framework were established, and its sedimentary evolution history was analyzed. It further defines the horizontal and vertical spatial distribution, evolution characteristics and the response relationship with the structure of each group of sedimentary facies, revealed that the sedimentation has a control relationship with all kinds of reservoirs, and established two typical coal accumulation models. On this basis, combined with gas logging data, the water and gas barriers and gas bearing systems are identified and divided within the sequence stratigraphic framework, the vertical distribution characteristics of coal seam gas content and the sealing characteristics of sequence structure on gas bearing systems are revealed, and the division of gas bearing systems of Late Paleozoic Coal measures are completed. There are two gas-bearing systems about Class I in sequence 2 of Taiyuan Formation and sequence 4 of Shanxi Formation.

 Enormous breakthrough have been made in shale oil exploration of Fengcheng Formation in Mahu sag, Junggar basin. However, according to generally accepted evaluation standard of shale oil source rock, the quality characteristics of source rocks in this area are not ideal. In order to scientifically evaluate the quality of source rocks in Mahu sag, the sedimentary environment of Fengcheng Formation was studied, and the source rocks was evaluated according to the mineral composition of fine-grained rocks on the basis of systematic core observation and organic geochemical analysis. Fine grained rocks of Fengcheng Formation in Mahu sag were mainly deposited in normal semi deep lake, salinized semi deep lake and semi-salinized semi deep lake, hydrothermal semi deep lake and shallow lake. The organic matter characteristics of fine grained rocks in each environment are different, and the semi-salinized semi deep lake was favored to enrich organic matter, and the averaged TOC was nearly 1%. Further combining with the discrimination diagram of organic matter types, it showed that the source of organic matter in salinized semi deep lake and hydrothermal semi deep lake was dominated by aquatic organisms, while there were mixed organic matter sources of lacustrine and land in other environments. Based on the hydrocarbon generation potential evaluation and maturity estimation of organic matter (Vre=0.74%), it was revealed that the source rocks of Fengcheng Formation were in the mature stage of hydrocarbon expulsion, and the free hydrocarbons in fine-grained rocks were identified as primary hydrocarbons. Finally, due to the difference of adsorption capacity of different mineral composition of source rocks, the classification evaluation is carried out according to continental argillaceous source rocks and carbonate source rocks. The results showed that the Fengcheng Formation deposited effective source rocks with a cumulative thickness of nearly 250 m, with organic matter dominated by algae.