Abstract:With special genetic mechanisms, adakitic rock is one of the important rock probes for exploring the deep magmatic dynamic process and regional tectonic evolution. In this paper, zircon U-Pb age, major and trace elements and zircon in-situ Hf isotopes of the Shiwali granite from the eastern part of the North Qilian orogenic belt were systematically analyzed to explore its petrogenesis and geodynamics significance. LA-ICP-MS zircon U-Pb dating yields an emplacement age of 452 ±4 Ma for the Shiwali granite, indicating a product of Late Ordovician magmatic activity. Bulk-rock analyses show that these rocks contain high SiO₂ (68.60%~71.42%), Al₂O₃ (14.95%~15.75%) and Na₂O (5.06%~5.79%) contents, with low K₂O (2.23%~3.10%) and MgO (0.91%~1.73%) contents, and resultant high Mg^# value (55~59), belonging to the weak peraluminous and calc-alkaline series of rocks. These rocks have high concentrations of Ba (1 025×10^-6~1 250×10^-6), Sr (324×10^-6~577×10^-6) and low Y (6.99×10^-6~7.69×10^-6), Yb (0.65×10^-6~0.71×10^-6) contents, with high Sr/Y (45~79) and (La/Yb)_N (17~31) values, and no significant negative Eu anomalies. The εHf(t) values of zircons are relatively high, with a range of +0.5 to +15.5. The geochemical and zircon Hf isotopic compositions of the Shiwali granites are similar to that of high-Mg adakites, which may be the product of partial melting of the basic lower crust of the island arc at a depth of 30~40 km, and there may be Early Paleozoic juvenile crust in the source area. Combined with the research results of ophiolites, high-pressure metamorphic rocks and arc magmatic rocks in the study area, we suggest that the Shiwali high-Mg adakitic granites might be generated during the southward subduction of the oceanic crust in the Laohushan back-arc basin in the Late Ordovician, which affected by the northward subduction of the North Qilian Proto-Tethys ocean.

Abstract:In order to explore the petrogenesis of quartz diorite porphyry and the ore-forming contribution of mantle-derived basic magma, this paper present LA-ICP-MS zircon U-Pb dating, Hf isotope and whole rock geochemical study for quartz diorite porphyries from Dexing porphyry Cu deposit. The LA-ICP-MS zircon U-Pb age of quartz diorite porphyries obtained is 169 Ma, in accordance with that of ore-forming granodiorite porphyries, indicating that they were emplaced during the middle Jurassic. The quartz diorite porphyries are characterized by low SiO₂ (58.41%~63.12%), K₂O (1.68%~2.94%) contents and A/CNK values(0.85~1.04), belonging to the calc-alkaline to high-potassium calc-alkaline rocks. They are enriched in large ion lithophile elements and light rare earth elements but depleted in high field strength elements Nb, Ta, Ti, and heavy rare earth elements. The Hf isotope composition of zircon with relative depletion, εHf(t)=2.20~7.93 (maximum 7.93), indicating that they were crystallized from lithospheric mantle-derived magmas. The zircon REE distribution pattern diagram shows an obvious positive Ce anomaly, and the magmatic oxygen fugacity (lg f_O2) varies from-20.05 to -6.66, reaching the magnetite to hematite oxygen fugacity buffer, indicating that they were crystallized from magma with high oxygen fugacity. Geochemical results show that quartz diorite porphyries, granodiorite porphyries (and the enclosed enclaves) conform to the evolution trend of magma mixing, which indicates that the ore-forming granodiorite porphyry may be the product of large-scale mixing of mantle-derived basic magma and crust-derived acidic magma in the Middle Jurassic, and the quartz diorite porphyry represents the mantle-derived basic end member in the process of magma mixing. Combined with previous research results, it is believed that quartz diorite porphyries in the Dexing deposit were generated by melting of subduction-modified lithospheric mantle, which was triggered by upwelling of the asthenospheric mantle related to the extensional setting during the middle Jurassic in South China. Underplating of the mantle-derived basic magmas could have provided heat for melting of the lower crust and subsequently mixed with the crust-derived acidic magmas, which generated the parent magmas of ore-forming granodiorite porphyries. In addition, the magmatic system of quartz diorite porphyry was highly oxidized, which was favorable for preventing the early sulfide saturation and contributing volatiles and metals to the Dexing ore-forming systems.

Abstract:The Xiangshan uranium orefield in Jiangxi Province is one of the largest volcanic-related uranium orefields in China. The Penggushan district is located in the western part of the Xiangshan uranium orefield, close to the Julongan and Zoujiashan large uranium deposits, and has favorable minerogenetic conditions. In recent years, a significant breakthrough in the exploration of uranium deposits has been made in the Penggushan area, where the hydrothermal alterations are high-temperature alteration with less later superimposed alteration, so it is an ideal place to study the relationship between high-temperature hydrothermal alteration and uranium mineralization. In view of this, on the basis of a field geological survey, this paper analyzes the geochemical characteristics of hydrothermal alteration in Penggushan area through petrographic and whole rock geochemical analysis and discusses the characteristics of high-temperature hydrothermal alteration and its relationship with uranium mineralization. The results show that the high-temperature hydrothermal alterations are commonly dominated by albitization, desilication, chloritization, and illytization, and locally overprinted by apatitization, pyritization, carbonation, and silicification. The uranium mineralization shows a close spatial relationship with the albitization, apatitization, carbonation, and desilication. In the Penggushan district, uranium mineralization is alkali-metasomatized and formed in a medium-high temperature reductive environment. The occurrence of apatite in fluid is possibly an important factor for the formation of high-grade mineralization in the study area. Apatitization and carbonation superimposed on alkali metasomatic alteration are most strongly developed in the ore body, which are regarded as the most important prospecting indicators in future uranium resource exploration of Penggushan area.

Abstract:The Shizhushan wollastonite deposit in Jiangxi Province is the world's largest reserve of wollastonite deposits and is located in the Pingle Depression of the eastern Qinhang metallogenic belt. In order to clarify the nature of ore-forming fluids and further prospecting potential in the area, this paper divides the garnet of the deposit into early (GrtⅠ) and late (GrtⅡ) generations according to the interpenetration relationship and optical characteristics between minerals. On the basis of detailed field work, this paper systematically studied the garnet in Shizhushan deposit by using electron probe analysis (EMPA) and LA-ICP-MS in-situ microanalysis technology. The results show that the garnets in Shizhushan wollastonite deposit belong to the grossularite to andradite solid solution series. The early generation garnet (GrtⅠ) has higher Fe content and developed oscillatory zoning, while the late generation garnet (GrtⅡ) has complex zoning. GrtⅠ and GrtⅡ are depleted in large ion lithophile elements (LILE) such as K, Rb, Ba, Sr, etc., while high field strength elements (HFSE) such as Nb, Ta, Zr are relatively high, and U content is proportional to ∑REE. The ∑REE of GrtⅡ is low (12.92×10^-6~21.12×10^-6), with a flat REE distribution pattern, slightly enriched in LREE (Ce, Pr, Nd, Sm), and weak Eu anomaly. The ∑REE of GrtⅠis higher (13.78×10^-6~73.52×10^-6), and it is more enriched in LREE (Ce, Pr, Nd, Sm) than GrtⅡ. The distribution pattern of rare earth elements is "right-inclined type", and the negative Eu anomaly is obvious. GrtⅠis formed in an acid system with relatively open, high water-rock ratio and high oxygen fugacity. GrtⅡ was formed in a relatively closed intermediate-acid system with low water-rock ratio and high oxygen fugacity, while GrtⅡ is formed in a relatively closed intermediate acid system with low water rock ratio and high oxygen fugacity. In addition, the composition and trace element characteristics of garnet are compared with those of contact metasomatic metal deposits of different minerals in domestic and abroad. The results show that the deposit has the potential to form Cu, Fe and Mo ore bodies.

Abstract:The Dulanggou gold deposit is a typical quartz vein type gold deposit, which is located at the edge of the dome in the Danba metallogenic belt. A large number of visible gold and tellurium-bismuth minerals are developed in the deposit. Taking tellurium-bismuth minerals and native gold in Dulanggou gold deposit as the main research object, the occurrence states of tellurium-bismuth minerals and native gold in the deposit were studied in detail through microscopic petrography observation, scanning electron microscope, energy dispersive spectrometer and electron probe analysis. Simultaneously, the enrichment mechanism of gold was also discussed. The results show that native gold and tellurium-bismuth minerals were mainly produced in the Ⅱ and Ⅲ mineralization stages of the Dulanggou gold deposit. The native gold in the Ⅱ and Ⅲ mineralization stages is mainly silver-bearing native gold, and the gold fineness is high with an average of 881, the main tellurium-bismuth minerals are tsumoite, pilsenite, hedleyite, joseite B, unnamed tellurium-bismuth minerals(Bi₂Te、Bi₈Te₃、Bi₃Te) and native bismuth. These tellurium-bismuth minerals have a close relationship with native gold in time and space. Combined with previous studies on fluid inclusions, it is suggested that the decrease of temperature and tellurium fugacity in the system from mineralization stage Ⅱ to stage Ⅲ are the important reasons for the formation of various tellurium-bismuth minerals. The physical and chemical conditions of the mineralization of the Dulanggou gold deposit, as well as the mineral characteristics of tellurium-bismuth minerals and native gold, indicate that the extraction of gold from the hydrothermal solution by the gold-bismuth-tellurium melt during the mineralization process is the key to the enrichment of native gold in the mineralization process.

Abstract:A series of Yanshanian magmatic hydrothermal Cu, Sn polymetal deposits have been reported in Eastern Inner Mongolia Huang Gang-Ganzhuermiao tin and copper polymetallic metallogenic belt, such as Dajingzi, Anle, Maodeng and Aonaodaba. These deposits are mainly hosted in Permian, but the genetic link between Permian and metallogeny is still unknow. Based on our new discovery of sulfide pressure shadow in Permian slate and detailed petrographic and SEM/EDS, in-situ isotopic results, this paper discusses the genesis Permian wall rock in Hongling Pb-Zn-polymetallic deposit and their contribution to Cu, Zn skarn in the area. The results show that the main wall rock of Hongling deposit are Permian marine volcanic and sedimentary rocks. The slate of the deposit has a slightly deformed volcanic origin, and shows pyroclastic texture and with mainly quartz, K-feldspar as the pyroclasts with minor zircon, apatite, ilmenite, and spinel pyroclasts. The cement composited of micro-grained biotite, quartz, K-feldspar, and plagioclase. The pressure shadow comprises a sulfide core and a quartz and chlorite shadow trending along the schistosity of the slate and deformed together with the bedding. The pressure can be crosscut by hydrothermal vein of main ore-stage which shows no fold deformation. The sphalerite and chalcopyrite in the shadow and their similar S isotopic composition (-0.33‰~+1.75‰) with the sulfide in skarn ore implying a contribution of Permian to the mineralization in the area. The results are helpful for understanding the Cu and Zn mineralization in the area and have important guiding to regional exploration.

Abstract:Lamprophyllite group minerals are the general name of titanosilicate minerals rich in Sr, Na, Ca and Ba etc. So far, there are 19 mineral species, of which fluorlamprophyllite was found in the alkaline rocks of the Serrote Mountain in Brazi for the first time. In this paper, the mineralogical characteristics of the lamprophyllite group minerals in the Saima alkaline rock pluton in Liaoning Province, China, have been studied in detail in terms of chemical composition and crystal structure by means of electron probe micro-analysis and X-ray diffraction. The results show that the minerals occur mainly in columnar, acicular and fibrous aggregates, and the single crystals are in sheet and plate shape. The crystal chemical formula is (Sr_1.00Na_1.00)_Σ2.00Ti₂(Na_1.98Sr_0.33Mn_0.26K_0.12Mg_0.10Ca_0.09Ba_0.05)_Σ2.93(Ti_0.69Fe³⁺_0.33Al_0.02)_Σ1.04(Si_3.80O₁₄) O₂(F_1.16OH_0.84)_Σ2.00. It belongs to monoclinic system, with the space group of C2/m. The unit-cell parameters are a=19.271 9(8) Å, b=7.077 9(3) Å, c=5.388 2(2) Å, β=96.780(2)°, V=729.84(5) ų, Z=2. The mineralogical characteristics mentioned above are consistent with those of fluorlamprophyllite which is a new mineral discovered in the alkaline rock of the Serrote Mountain in Brazil for the first time, and the fluorlamprophyllite studied in this paper is the first discovered in China. At the same time, it is pointed out that the Saima alkaline pluton also includes lamprophyllite, and it implies that there is still a good prospect for the discovery of new minerals in the pluton because of its special element combination and formation conditions.

Abstract:The beryl family is known for its wide range of colors and has always been an important gemstone variety in the market. Over the past few decades, scholars both domestically and abroad have conducted extensive research on the coloration mechanism and color-modification techniques of beryls of different colors. As one of the important coloration transition-metal ions, the valence state regulation of iron ion is critical in the color-modification process of beryls. Therefore, the valence state, site occupancy, and corresponding chromogenic effects of iron ions have always been the focus of beryl research. Iron ions are believed to exist in various sites within the beryl crystal structure, including the aluminum octahedral Al³⁺ site, silicon tetrahedral Si⁴⁺ site, beryllium tetrahedral Be²⁺ site, structural channel 2a or 2b site, and lattice interstitial site 6g, and are the main color-causing elements for blue, green, or yellow beryls. Through a review and comprehensive analysis of the literature on the crystal structure of beryl, site occupancy and the arrangement of outer electrons of iron ions, we suggest that Fe²⁺ and Fe³⁺ play a dominant role in the coloration of blue and yellow beryls, respectively. Further research is needed to determine the specific differences in color-causing effects when Fe²⁺ and Fe³⁺ are located in different sites within the lattice.

Abstract:The determination of lead content in new cerium iron boron material has been studied and a new method of determination of lead content in cerium iron boron by inductively coupled plasma optical emission spectrometry (ICP-OES) has been developed. The selection of analytical spectrum lines was studied. Cerium and iron were used as matrix to prepare the standard solutions, and the content of lead in cerium iron boron was determined by matrix matching method. Finally, the reliability of the method was verified by calculation of detection limit, standard recovery test, parallel test and repeatability test. The test results showed that the detection limit of the method was 0.007 mg/L, the recovery rate was 100.6%, and the content of lead in the sample was 0.006%. The parallelism between the two tests was good, and the repeatability was lower than 2.3%. This method is feasible in laboratory, and can provide a basis for the analysis of lead content impurity in the production of new cerium iron boron, as well as a reference for the detection of heavy metal pollution.

Abstract:Petrology and mineralogy are important branches of Earth Science, and related research can provide in-depth understanding of significant scientific issues such as planetary formation and evolution, resource enrichment, and environmental changes on habitable Earth. Acta Petrologica et Mineralogica is an important domestic journal in the field of petrology and mineralogy. In-depth exploration of the articles published in the journal helps to sort out the research progress and provide background information for discipline practitioners to conduct further research. It can also provide a reference for the journal's future direction of publication. This paper conducts quantitative research on the arcticles published in Acta Petrologica et Mineralogica from 1982 to 2022 using big data analysis and visualization technologies. The research found that petrology and mineralogy have always been the main focus of the journal. Geochemistry, granite, zircon U-Pb dating, adsorption, and mineralogy are hot keywords of publication. Among them, "geochemistry" has the highest co-occurrence intensity, closely related to keywords such as granite, rock genesis, volcanic rocks, and petrology; followed by lattice parameters, with relevant keywords such as optical properties, powder diffraction data, and new minerals. The specific research topics include five different themes, such as rock composition and characterization analysis, study of metamorphic processes and rock metamorphism, characteristics of mineral deposits and ore-forming processes, analysis of sedimentary environments and stratigraphic features, and research on environmental mineralogy. Compared with data from renowned domestic and international journals in the field of petrology and mineralogy, it is believed that future publications should encourage the development and application of new technologies and methods, interdisciplinary research, and new paradigm research driven by big data and machine learning.