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    Volume 43,2024 Issue 3
      前言
    • QIAN Xue-wen, LI Jing-jing, YANG Li, XU Ya-fen

      2024,43(3):495-502, DOI: 10.20086/j.cnki.yskw.2024.0301

      Abstract:

      X-ray powder diffraction, infrared spectroscopy, electron microprobe, laser ablation inductively coupled plasma mass spectrometry and ultraviolet-visible spectrophotometer were used to test and analyze the phase composition and color genesis of different shades of pink opal samples from Peru. The results show that the main mineral composition of pink opal is Opal-CT, palygorskite, quartz and water, and the type of water is rich, including crystal water, structural water and zeolite water. Combined with X-ray powder diffraction, electron microprobeand infrared spectrum analysis, it is considered that the color of pink opal is related to palygorskite, and the content of palygorskite was quantitatively analyzed by XRD, which was positively correlated with color. UV-visible spectrophotometer combined with electron microprobe and laser ablation inductively coupled plasma mass spectrometry showed that the color of pink opal was related to the organic quinones, β-carotene and Mn2+, and the more the content of Mn2+, the darker the color. At the same time, the effect of Fe3+ on color was proposed, and it was found that Fe3+ only appeared in dark samples.

    • YANG Shu-qi, LIU Ying-xin

      2024,43(3):503-517, DOI: 10.20086/j.cnki.yskw.2024.0302

      Abstract:

      The natural Tanzanian zoisite (tanzanite), with its distinctive blue-violet tone, is a rare and valuable gemstone. Heat treatment can optimise the color of zoisite and make it more economically valuable. However, the exact cause of this captivating blue-violet of zoisite has been a subject of debate for years. This study presents an examination of natural yellow and blue zoisites. The color changes of stones at different thermal stages were observed by setting three different temperature conditions 300℃, 400℃ and 500℃, and using the L*a*b* color parameter. The research findings indicate that the gemological properties of different colored zoisites remain consistent before heat treatment. It was determined that a temperature of approximately 500℃ is optimal for achieving a light blue-violet tone in zoisite. Heat treatment results in a pronounced enhancement of the blue-violet hues, enabling the modulation of zoisites’ yellow or brown undertones through temperature control. Notably, the yellow zoisite experiences a fascinating color transformation from yellow-brown to blue-violet, with the critical temperature range between 400℃ and 500℃. Using energy dispersive X-Ray spectroscopy (EDXRF), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and ultraviolet and visible spectrophotometry (UV-VIS) techniques, the study identified that the blue color in natural zoisite is primarily caused by V3+ and Ti3+ ions working in tandem. On the other hand, the yellow color is mainly attributed to Ti3+. The V/Ti ratio plays a supporting role in coloration of natural zoisite. Moreover, the development and intensification of blue-violet tones in heat-treated zoisite, as well as the transition from yellow to blue-violet, are intricately linked to the charge migration of Ti3++V4+→Ti4++V3+.

    • TANG Jun, CHEN Yang-ling, GUO Ying, HE Qing, QIN Qiao-hong

      2024,43(3):518-524, DOI: 10.20086/j.cnki.yskw.2024.0303

      Abstract:

      Photochromism is the most significant and valuable optical characteristic in hackmanite. EDXRF, FTIR, UV-VIS-NIR, D65 standard light source, illuminator and colorimetry method were applied in this paper to study the decolortation efficiency of photochromism in hackmanite from Mogok, Myanmar (Burma). The results indicated that the major elements of hackmanite are Na, Al, Si, O, Cl and S, its trace elements should include Ca, K and Fe. There are three absorption peaks of 472, 540 and 667 nm in UV-VIS-NIR spectrum, with 540 nm having the strongest absorption peak. The peaks stay stable but their intensity decrease with time during decoloration. The absorption peak area of 540 nm is significantly negative corelated with time during 0~80 s (R2=0.99). The decoloration efficiency grows significantly when the luminance increases from 5 000 lx to 30 000lx. During decoloration, the lightness of hackmanite color increases, while its chroma decreases. The color parameter a* decreases and b* increase. Its hue turns from purple to pink slightly. All the color effect of photochromism in hackmanite is a direct result of charge transfer leading to the destruction of the F center in hackmanite.

    • ZHENG Yu-yu, YU Xiao-yan, XU Bo, GUO Hong-shu, YAN Ying, ZHANG Yi, TANG Jun, ZHAO Si-yi

      2024,43(3):525-561, DOI: 10.20086/j.cnki.yskw.2024.0304

      Abstract:

      Emerald is a precious colored gemstone, and its origin has a significant impact on the evaluation of its value. The identification of the origin of emerald has become an important technology in gemstone laboratories and a research hotspot in the field of gemology. The inclusion, spectral characteristics, and chemical composition of emerald are commonly used and critical information for origin determination. However, with the accumulation of research data on the origin of emerald, traditional methods for origin determination are facing challenges. This article systematically summarizes and analyzes the gemological characteristics, inclusion information, spectral features, and major and trace element data of emeralds from various occurrences around the world. Based on a review of previous research results, it systematically elucidates the current research status of emerald origin determination, summarizes the gemological characteristics and inclusion characteristics, reveals the component fingerprint of emeralds from each occurrence, and uses case studies to illustrate the methods of distinguishing common and important origins of emeralds. Although the comparison at a global scale indicates that the inclusion varieties of emerald from different origins are mostly similar, with spectral convergence and significant overlap in component content ranges, novel approaches for origin determination are proposed based on inclusion frequency, UV-VIS-NIR spectral patterns, absorption patterns of HDO and D2O, and the parameter selection of compositional diagrams.

    • TANG Gan-yu, LAI Yong

      2024,43(3):562-574, DOI: 10.20086/j.cnki.yskw.2024.0305

      Abstract:

      As one of the four famous inkstones in China, She inkstone has high economic and artistic value. She inkstone samples were collected in Wuyuan, Jiangxi Province. To explore the causes of the unique texture of She inkstone, and the mechanism of ink generation in She inkstone, this paper has observed and tested samples under optical microscope, environmental scanning electron microscope (ESEM), energy dispersive spectroscopy (EDS) and electron microprobe (EMPA). The results have indicated that the main minerals of She inkstone include sericite, quartz and chlorite. It has also found that the She inkstone’s different texture is controlled by the degree of metamorphism of primary minerals and the stress deformation of original rock. Combining its microscopic structure and inkstone edge mechanism, quartz provides coarse grinding, sericite and chlorite provide fine grinding during the ink-making process. By calculating the density of She inkstone’s edges, this paper argued that She inkstone is belong to high-density group, and quantitatively evaluated the practical properties of She inkstone from a numerical perspective. Combined with self-sharpening edge mechanism, this paper explains why She inkstone can maintain excellent ink-making performance for a long time. In comparison with other inkstones, She inkstone shows outstanding advantages in both ornamental and practical aspects.

    • DING Zhi-dan, ZOU Yu, WANG Die

      2024,43(3):575-591, DOI: 10.20086/j.cnki.yskw.2024.0306

      Abstract:

      Aquamarine belongs to the beryl group minerals and is produced in granite pegmatites. Its crystallization process can run through different stages of the evolution of pegmatitic magma, and it is also an important host mineral for magma melts and fluid inclusions. Kujierte pegmatite is an LCT type pegmatite that can produce high-quality aquamarine among numerous pegmatite veins in the Koktokay area of Altay, Xinjiang. This article investigates the main, trace elements, and fluid inclusions of aquamarine produced in Kujierte pegmatite. Fluid inclusion petrology shows that the distribution of melt/melt fluid inclusions (MI/M-FI) and fluid inclusions (FI) in aquamarine exhibits a certain pattern: MI/M-FIs are mainly concentrated from the root to the middle of the crystal, while FIs are enriched in the edge region, indicating that the crystallization process of the aquamarine has undergone a relatively complete stage of pegmatite magmatic evolution. The temperature measurement results show that the homoge-nization temperature of M-FIs is >550℃, and the homogenization temperature range of FIs is 220~400℃, with salinity ranging from 0 to 14% and density ranging from 0.6 to 0.9 g/cm2. The fluid belongs to H2O-NaCl-CO2 system with the medium high temperature and medium low salinity. Based on the orientation of crystal crystallization and the distribution of fluid inclusions, the magma hydrothermal transition stage and post magmatic hydrothermal stage were divided. Electron probe analysis (EPMA) and laser ablation plasma mass spectrometry (LA-ICP-MS) analysis results showed that Fe element dominated the coloration of aquamarine. During the growth process of aquamarine, Fe2+ entered the mineral lattice in a channel octahedral substitution mode of Na++Fe2+→ Al3+, resulting in a light blue coloration. In the early to middle stages of the evolution of pegmatites, the content of alkali metals (Li, Na, K, Cs) and transition metal (Fe, Mg, Mn) elements in aquamarine remained stable, and in the late stage, the content of these metal elements increased sharply. Combined with the long-term compression and subduction of plate in the region, which has led to the overflow of deep material in the earth, and the evolution of pegmatite magma in an unclosed system, it is believed that the fluid enriched with Fe, Mg, and Mn in the deep magma chamber was injected in a pulsating manner in the late stage, resulting in a fluctuating change in the composition of the original hydrothermal fluid.

    • LIANG Rong, LAN Yan, GAO Kong, ZHANG Xiao-hu, CHEN Mu-yu, WANG Hong-hao, LU Tai-jin

      2024,43(3):592-598, DOI: 10.20086/j.cnki.yskw.2024.0307

      Abstract:

      In order to improve the screening efficiency and accuracy of batch small particle diamonds, this paper developed a new type of ultraviolet photoluminescence image high-speed acquisition device—jewelry observation and identification instrument (DDO). Through the selection of excitation light source, industrial camera, structural design technology breakthroughs, and innovation in the collection method of luminescence phenomena, it achieved batch observation of photoluminescence phenomena and luminescence delay differences between different gemstones, thereby achieving efficient detection of gemstones. The DDO test results on over 20000 colorless natural diamonds, synthetic diamonds, and imitation diamonds show that 98% to 99% of colorless natural diamonds exhibit a blue phosphorescence phenomenon within 0.1~10 ms after the cessation of ultraviolet light excitation, which is a typical feature of natural diamonds. The luminescence characteristics (luminescence color, intensity, duration, structural zoning) of synthetic diamonds and other colorless gemstones are significantly different from natural diamonds. Therefore, a new method for rapid and accurate screening of colorless natural diamonds is established by observing the differences in continuous luminescence (phosphorescence) characteristics, including fluorescence and decay time within 100 ms, as screening conditions. This device improves the accuracy and detection efficiency of diamond identification, with a screening pass rate of up to 99% for natural diamonds and 100% for synthetic and imitation diamonds.

    • LIU Fu-kang, GUO Ying, LIU Wei-ming, ZHAO Bei, LIU Xin, SONG Yuan-meng

      2024,43(3):599-610, DOI: 10.20086/j.cnki.yskw.2024.0308

      Abstract:

      This study conducted corrosion experiments on different types of pearls, including heating, ultraviolet radiation, sweat, shower gel, and sunscreen, to analyze the effects of these corrosion methods on the color and chemical composition of pearls. The results show that heating has the least impact on the decrease of pearl color, while sunscreen and shower gel have the greatest corrosion effect. Gold pearls exhibit the most significant decrease in color under various corrosion methods. In the chemical composition analysis of pearls before and after corrosion, it was found that various corrosion methods generally led to an increase in Ca content and a significant decrease in Si content on the surface of pearls. The content changes of Mn and Sr are related to the type of pearl and the corrosion method. Exploring the effects of different external conditions on the color changes of pearls can provide reference for museum exhibitions and consumer purchases.

    • XIAO Qi-run, LIU Ying-xin

      2024,43(3):611-618, DOI: 10.20086/j.cnki.yskw.2024.0309

      Abstract:

      This study comprehensively analyzed the basic gemological characteristics, X-ray fluorescence spectroscopy (XRF), infrared spectroscopy, Raman spectroscopy, and other aspects of green apophyllite samples with different tones in the Huanggangliang area of Inner Mongolia, and systematically explored the chemical composition and spectral characteristics of green apophyllites samples with different tones. Through high-pressure X-ray diffraction (HPXRD) spectroscopy testing, the crystal structure characteristics of the mineral under high-pressure environment were analyzed in depth, providing key clues for revealing the stable depth of existence of apophyllites after subduction into the crust during geological movement. The research results indicate that the apophyllites in the Huanggangliang area of Inner Mongolia belong to fluorine apophyllites, the content of Fe3+ and crystalline water exert a significant influence on the intensity of the green color in apophyllites. In the HPXRD experiment, as the pressure increases, the axial length and cell volume of apophyllites gradually decrease, especially the compression rate of the c-axis is higher than that of the a-axis. At the pressure nodes of 9.0 GPa and 15.3 GPa, a sudden change in compression rate was observed, accompanied by the emergence of new diffraction peaks and the splitting and disappearance of old diffraction peaks. This discovery reveals two distinct phase transitions of apophyllites crystals in high-pressure environments. This study provides strong scientific basis for identifying apophyllites and searching for mineral resources, and also provides a new perspective and understanding for further research on apophyllites in the field of geology.

    • CHEN Yi-fang, JIN Xue-ping, LIU Zi-qi, ZHOU Zheng-yu, ZHENG Jun-hao, GUAN Qi-yun, CHEN Qi

      2024,43(3):619-629, DOI: 10.20086/j.cnki.yskw.2024.0310

      Abstract:

      The conventional gemological properties, chemical composition, crystal structure, and inclusions composition and characteristics of the Nigerian gahnite were analyzed in depth by conventional gemological testing, electron probe, single crystal X-ray diffraction, and Raman spectroscopy. The gahnite exhibits well-preserved octahedral crystal morphology, strong vitreous luster, and semi-transparency, with a relative density ranging from 4.48 to 4.61 and a refractive index of 1.792 to 1.794, displaying inert fluorescence under ultraviolet light. The electron probe analysis determined its chemical formula as Zn(0.87~0.92)Fe(0.06~0.07)Al(1.98~2.01)O4. Single-crystal X-ray diffraction revealed a cubic crystal system with space group Fd3m, lattice parameter a=8.089(2)Å, tetrahedral bond length T—O=1.953(4)Å, and octahedral bond length M—O=1.912 9(19)Å. Characteristic Raman absorption peaks for gahnite were identified at 418 cm-1 and 659 cm-1, corresponding to the Eg mode and high-frequency T2g(3) mode, respectively. Raman spectroscopy of inclusions confirmed the presence of various minerals in gahnite, including sphalerite, albite, muscovite, quartz, beryl, zircon, and phenacite. Combined with previous studies, it is believed that gahnite in Nigeria is formed in granite-pegmatite rich in Li, Cs, Rb, Be and Ta.

    • FU Yu-lei, SHI Miao, CAO Qin-yuan, MA Shi-yu

      2024,43(3):630-642, DOI: 10.20086/j.cnki.yskw.2024.0311

      Abstract:

      In recent years, a kind of black cyan nephrite containing pyrite has appeared in the domestic market. It is mainly produced in Xinjiang and belongs to a relatively rare nephrite variety, which has mining and utilization value. This article systematically analyzed the mineralogical and geochemical characteristics of seven samples using conventional gemological instruments, polarized light microscopy, infrared spectroscopy, Raman spectroscopy, X-ray powder diffraction (XRD), electron probe (EPMA) laser inductively coupled plasma mass spectrometry (LA-ICP-MS), and isotope mass spectrometer (MC-ICP-MS). The results show that the color of black cyan nephrite is dark green to black, the refractive index is 1.61, the relative density is 3.08~3.17, and the Mohs hardness is 6.0~6.5. The main component mineral is tremolite, the secondary mineral is mainly pyrite, and a small amount of chlorite, epidote, sphene, zircon, and graphite are also contained, with a typical fiber interlaced structure; The characteristic peaks of infrared and Raman spectra are consistent with the standard peaks of nephrite; The main chemical components of the sample are SiO2, MgO, CaO and FeO. The Mg/(Mg+Fe2+) value indicates that some tremolite has transitioned to actinolite. Based on the trace element Cr-Ni mapping, the sample is identified as a dolomite marble type genesis, while the content of rare earth elements is relatively low, in a left leaning mode, The ore-forming hydrothermal fluid is mainly magmatic water, containing a small amount of metamorphic water. The sample contains pyrite with Co/Ni>1 and small amounts of As, Se, Cu, Zn and Pb, δ34S ranges from 8.87‰ to 20.92‰, suggesting that it is of magmatic-hydrothermal origin and the source of sulfur is a mixture of magma and formation sulfur.

    • SHANG Yan-ran, WANG Wei-zhao, JIN Tian-li, HUANG Lin-ming, WU Zhong-yun, GUO Ying

      2024,43(3):643-651, DOI: 10.20086/j.cnki.yskw.2024.0312

      Abstract:

      55 Myanmar purple jadeite-jades samples were comprehensively analyzed by electron microprobe analysis (EMPA), energy-dispersive X-ray fluorescence (ED-XRF) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-VIS) spectroscopy and colorimetric methods. The results show that the main chemical compositions of Myanmar purple jadeite-jades are SiO2, Al2O3 and Na2O, and the contents are close to those of standard jadeite. Chromaticity test analysis showed that the chroma C* of purple jadeite-jade is mainly controlled by the colour coordinate a*, while the hue h° is mainly controlled by the colour coordinate b*. Myanmar purple jadeite-jades can be classified into two types: Type Ⅰ show the main absorption bands at 570 nm which is assigned by chromophore Mn3+ and Type Ⅱ with two main absorptions at 540 nm and 610 nm are colored by charge transfer between Fe2+-Ti4+. The absorption peaks of Fe3+ existed in both types of Myanmar purple jadeite-jades, and the full iron content in the samples determined their hue and lightness.

    • NIU Jia-rui, GUO Ying

      2024,43(3):652-662, DOI: 10.20086/j.cnki.yskw.2024.0313

      Abstract:

      The color characteristics, chemical composition and spectroscopic characteristics of the yellow-red Huanglong jade samples from Myanmar were studied through Fourier transform infrared spectrum, laser Raman spectrometer, ultraviolet-visible spectroscopy, an X-ray fluorescence spectrometer, electron microprobe analyzer, and an X-Rite SP62 hand-held spectrophotometer. The quantitative relationship between the color and spectral characteristics of Huanglong jade from Myanmar was analyzed. The results show that yellow-red Huanglong jade from Myanmar is mainly composed of SiO2, with small amounts of Fe, Cu, Cr and other transition metal elements, and belongs to the cryptocrystalline quartz jade. Under CIE D65 standard light source and N9 Munsell neutral background, there is a high correlation between the lightness and the hue angle of the Huanglong jade from Myanmar, and the change of iron content has a significant effect on the lightness and hue angle of the Huanglong jade from Myanmar. The first derivatives of the ultraviolet-visible absorption spectra can infer the relative contents of goethite and hematite in the Huanglong jade from Myanmar, and the color of the Huanglong jade from Myanmar changes from yellow to red as the position of the primary wave trough shifts toward the long-wave direction.

    • GUO Yi-lin, GUO Ying

      2024,43(3):663-672, DOI: 10.20086/j.cnki.yskw.2024.0314

      Abstract:

      Yellow silicified scleractinia has gained popularity in the market due to its unique pattern and beautiful color. To comprehend the structural characteristics and color origin of silicified scleractinia, three natural yellow silicified scleractinia were studied using X-ray powder diffractometry, polarising microscopy, thermal field emission scanning electron microscopy, UV-visible spectrophotometry, and Raman spectroscopy. There are differences in the morphology, species, and distribution of quartz particles in the space and the septa area of the scleractinia samples. The quartz particles will develop along the inner wall to the center, with irregular fine grain, xenomorphic medium grain, and xenomorphic semidiomorphic coarse grain when the space between the septa and the theca or the coenosteum is sufficiently large. The quartz particles are mainly xenomorphic or fibrous fine quartz when the cavity is compressed. In the septa area, the quartz particles are mainly fine quartz. The yellow and brownish-red minerals in silicified scleractinia observed under a polarizing microscope were confirmed to be goethite and hematite, respectively. Hematite is the main cause of the yellow color in silicified scleractinia. Due to the influence of coral bone structure, goethite and hematite always exist in the space of very fine or fine quartz particles in the microcosmic form of pigment points. They are enriched in the septa area and the margin of space.

    • CHEN Xing-yun, ZHANG Liang, WANG Hao-shuai, ZHANG Rui-rui, SUN Si-chen

      2024,43(3):673-684, DOI: 10.20086/j.cnki.yskw.2024.0315

      Abstract:

      Yunxiao is a significant producing area of gem-quality garnet in China. However, the color origin of garnet in this area remains ambiguous, which restricts the understanding of their formation mechanism and subsequent exploitation. In this paper, 7 samples of orange-yellow-orange-red garnet from Yunxiao, Fujian were selected, and the spectral characteristics of the samples were analyzed by Fourier infrared spectrum, UV-visible spectrum and Raman spectrum, and the characteristics of main and trace elements were defined by electron probe (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis. It is concluded that the color of the garnet is predominantly influenced by the absorption of visible light by Mn2+ and Fe2+. Mn2+ dictates the yellow tone of the garnet, while a minor amount of Fe2+ governs the orange-red tone. Additionally, a trace amount of Ti4+ imparts a brownish appearance to the garnet. The samples exhibited a relatively low manganese content and high iron and magnesium content in their core, a gradual increase in manganese content from the core to the rim. The samples also displayed a left-leaning partition pattern, with an enrichment of heavy rare earth elements and a deficit of light rare earth elements. Europium (Eu) showed a negative anomaly. These findings suggest that the garnets from Yunxiao, Fujian were formed during magmatic processes and are products of late-stage magmatic crystallization.

    • LI Yu-xuan, HUANG Ying, LIU Ying-xin

      2024,43(3):685-696, DOI: 10.20086/j.cnki.yskw.2024.0316

      Abstract:

      The Brazilian diamond samples were analyzed by conventional gemological testing instruments combined with Fourier transform infrared spectrometers (FTIR), laser Raman spectroscopy, and Diamond ViewTM. The results revealed that the surface microforms of Brazilian diamonds are extremely diverse, featuring various growth mounds, trigonal, hexagonal, or irregular fusion pits, as well as plastic deformation slip lines. The Brazilian diamond samples are predominantly composed of the ⅠaAB type, accounting for over 90% of the total samples. It exhibits a nitrogen content ranging from 400×10-6~1 700×10-6 and a B core conversion rate between 15% and 66%. These findings indicate that Brazilian diamond samples are characterized by a high nitrogen content and a low to moderate degree of nitrogen aggregation. Raman spectroscopy analysis shows that there is residual compressive stress or poor crystallinity inside the sample. Diamond ViewTM luminescence images reveal blue and yellow-green fluorescence is popular in Brazilian ⅠaAB diamonds. Type ⅠaB diamonds exhibit blue fluorescence with green hues and an uneven blue fluorescence. The Type Ⅱa diamond samples exhibit dark orange and blue fluorescence.

    • LI Wen-juan, YU Xiao-yan, BAI Feng

      2024,43(3):697-708, DOI: 10.20086/j.cnki.yskw.2024.0317

      Abstract:

      Henan Miyu jade is an important variety of jade in China, which belongs to the phanerocrystalline quartzite. A systematic geological study of the Miyu jade deposit in Xinmi City, Henan Province, has been carried out, but its gemmological characteristics and color genesis remain controversial. This paper synthesizes the research results of the previous researchers, and obtains the gemological characteristics, spectroscopic research characteristics and chemical composition characteristics of the green series of Henan Miyu jade samples by routine gemological testing, FTIR spectroscopy, UV-VIs spectroscopy, Raman testing and electron microprobe testing. The results show that Miyu jade is a quartzite with good crystallinity. The main mineral component is α-quartz, and minor minerals include muscovite, hematite, carbonaceous minerals, rutile, tourmaline, etc. It has a granular metamorphic structure and a microscopic fine-grained metamorphic structure. Significant characteristic absorption peaks of Cr3+ were seen in the UV-visible spectrum. The green color of Miyu jade is related to chromium-containing white mica, and the green color of chromium-containing white mica is caused by the trace elements it contains, such as Cr, V, Ni and other color-causing elements. The darker the green color, the higher the content of Cr, Ni and V. With the increase of Fe3+ content, the yellow tone of the sample is more obvious.

    • LI Jia-rong, LI Yan, WU Jia-xin

      2024,43(3):709-718, DOI: 10.20086/j.cnki.yskw.2024.0318

      Abstract:

      This paper presents a comparative study of the spectral characteristics of copal resins from six different origins: Russia, New Zealand, Borneo, Madagascar, Colombia, and Sumatra. The study uses gemstone microscopy, infrared spectroscopy, ultraviolet fluorescence observation, and three-dimensional fluorescence spectroscopy to identify the characteristics of the resins. The results indicate that the infrared spectra of Borneo and Sumatra copal resins are mainly characterized by four absorption peaks in the range of 3000~2800 cm-1, absorption peaks at 1708 cm-1 and a shoulder peak at 1732 cm-1, a weak absorption peak at 888 cm-1. Similarly, the main features of the infrared spectra of New Zealand copal resin are three absorption peaks in the range of 3000~2800 cm-1 and weak absorption peaks at 1 642 and 888 cm-1. The infrared spectra of copal resins from Madagascar, Colombia, and Russia exhibit similarities, with three combined characteristic absorption peaks associated with C=C, a strong absorption peak at 1 692 cm-1, and two absorption peaks of comparable intensity at 1270 and 1180 cm-1. Under long-wave UV fluorescence, the fluorescence intensity of Borneo and New Zealand copal is stronger than that of resins from other origins, but the fluorescence intensity of Borneo copal is significantly stronger and the fluorescence intensity of Madagascar copal is the weakest. Borneo and Sumatra copal resins emit three typical peaks at 445, 474 and 505 nm, which can be optimally excited by 416,447 nm. The strongest emission peak of New Zealand copal is at 385 nm, which can be best excited by 352 nm. The strongest emission peak of Russian copal is at 399 nm, which can be best excited by 354 nm. The strongest emission peak of Colombian copal is centered at 470 nm, which can be best excited by 400 nm; and the relative fluorescence intensity of Madagascar copal is the weakest, the strongest fluorescence peak is at 465 nm, which can be best excited by 378 nm. It was concluded that the fluorescence and infrared spectroscopic characteristics of the copal resin could provide a basis for the identification and classification of the resin.

    • 非主题来稿
    • CHENG Hai-feng, DU Li-lin, YANG Chong-hui, SU Rong-kun, MENG Qing-tao, LIU Guang, WANG Ming-ming, ZHANG Zheng-ping, JING Jing-jing, WANG Xiao-dong

      2024,43(3):719-736, DOI: 10.20086/j.cnki.yskw.2024.0319

      Abstract:

      The North China Craton (NCC) has undergone a long and complicated geological process. During the Mesozoic, a series of intermediate-acid granitoids were formed in the Taihang Mountains. Mapeng granitic pluton is located in the northern part of Taihang Mountains, emplaced in Fuping complex, with porphyritic monzonitic granite, granodiorite and quartz diorite exposed from the center to the edge. The petrology, petrochemistry, genetic type of Mapeng granitic pluton have been studied by predecessors, but the type and source of granitic pluton are still controversial. In this paper, the petrochemistry, zircon SHRIMP U-Pb isotopic chronology and Lu-Hf isotopic composition of porphyritic monzonitic granite, granodiorite and quartz diorite in Mapeng pluton are systematically studied, and the geochemical type, formation age and magma source nature of Mapeng granite are further discussed. Geochemical magmas show that the Mapeng granite has high SiO2、Na2O+K2O、Ba、Sr、LREE and the ratio of K2O/Na2O, lower Al2O3、MgO、Rb、Nb、Ta、Th、U、Y、HREE and Mg#value, no obvious Eu anomaly and obvious depletion of high field strength elements such as Nb, Ta, P and Ti. The SHRIMP U-Pb isotopic ages of the three newly obtained granites with different facies belts are 129.4±1.4 Ma, 131.2±2.2 Ma, 129.5±1.3 Ma, and they have similar major element compositions and REE and trace element distribution patterns. It also reflects that the Mapeng pluton is a magmatic activity of the same period, and has undergone rapid emplacement and cooling crystallization. Lu-Hf isotopic analysis shows that the εHf(t) value of magmatic zircon from the Mapeng granite is -27.00~-15.44, and the two-stage model age tDM2 is 2 358~1 765 Ma. The magma source of the Mapeng granite is the result of mixing of mantle magma and magma formed by partial melting of Precambrian metamorphic basement.

    • WANG Le-le, LIU Ping-hua, ZHOU Wan-peng, DU Li-lin, YANG Chong-hui, ZHANG Wen, CAO Qiu-xiang, CHEN Li-mei

      2024,43(3):737-775, DOI: 10.20086/j.cnki.yskw.2024.0320

      Abstract:

      The Changzhougou Formation is one of the oldest sedimentary cover on the Archean-Paleoproterozoic metamorphic basement of the North China Craton. The analysis for the U-Pb geochronology and Hf isotopes of the detrital zircons from the Changzhougou Formation is of great significance for exploring the formation age and source characteristics of the Changcheng System as well as the basement evolution. In this study, LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) and LA-MC-ICP-MS (laser ablation multiple inductively coupled plasma mass spectrometry) were employed to analyze detrital zircon U-Pb ages and rare earth element composi-tions and Lu-Hf isotopic compositions of samples from the Changzhougou Formation of the Changcheng System in the Wengcheng area, Zanhuang Complex, respectively. The main peak ages of detrital zircons in two sandstone samples is 2 500 Ma, and the detrital material of the quartz sandstones is mainly derived from the late Neoarchean metamorphic basement in the North China Craton, and the 207Pb/206Pb age of youngest detrital zircon is 1 822 Ma, combining with the 1850 ~ 1800 Ma metamorphic ages which was recorded by the Zanhuang metamorphic basement and the 1635 Ma age of magmatic zircon from the volcanic rocks in the upper Dahongyu Formation, further define that the initial depositional timing of Changzhougou Formation of Changcheng System in the Zanhuang Complex is later than 1800 ~ 1635 Ma. The εHf(t) values of the detrital zircon from one quartz sandstone sample vary from -6.8 to +5.2, and the corresponding two-stage model peak age is 2 820 Ma. Combined with the published Hf isotope results of 2900 ~ 2700 Ma magmatic zircons and detrital zircons from the Zanhuang Complex, it is further indicated that 2900 ~ 2700 Ma is the most important period of crustal growth in the Zanhuang Complex. Integrating with the published sedimentary and new geochronological data of the Changzhougou Formation of the central and southern parts of the Taihangshan area, it is speculated that the Changzhougou Formation in Wengcheng area was deposited in the continental rift basin.

    • QIU Jia-wei, LIU Xin-xing, XUE Zhe, ZHANG Juan, CHENG Jia-wei, LU Ke-xuan, WANG Meng, YANG Jun-feng, WANG Ying-xue

      2024,43(3):776-786, DOI: 10.20086/j.cnki.yskw.2024.0321

      Abstract:

      As one of the important antimony mining areas in China, a large number of antimony polymetallic deposits (points) have been discovered in the southern Hubei antimony mining area. With the depletion of shallow antimony ore resources, there has been no new progress in the exploration of middle and deep parts. Therefore, there is an urgent need to find a fast and effective exploration method, conduct in-depth research on the exploration model and prediction of the area, in order to expand the amount of resources and exploration results. This article takes the Jinyinshan antimony polymetallic deposit as the research object. Short wave infrared spectroscopy (SWIR) technology was used to scan the rock cores of ZK3101 and ZK2701 boreholes in Jinyinshan antimony deposit, obtaining information on the types, combinations, and spectral parameters of altered minerals in Jinyinshan antimony deposit. The altered mineral zoning was divided, and the relationship between mineralization and altered mineral zoning was analyzed. The main altered minerals in the Jinyinshan antimony gold deposit include mica, chlorite, carbonate, etc. Among them, the sericite mineralization zone is closely related to mineralization. By calculating the Al—OH spectral characteristic parameters of sericite minerals, it was found that the crystallinity (IC value) of sericite at the mineralized site and the absorption peak value (Pos 2200) of the Al—OH 2200 nm characteristic peak showed low value anomalies (IC<2, Pos 2200<2205 nm), which can be used as an effective indicator of mineralization. It is believed that the application of shortwave infrared spectroscopy technology can quickly delineate antimony gold deposits, effectively guide mineral exploration, reduce exploration costs, improve exploration efficiency, and achieve breakthroughs in mineral exploration.

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    Volume 43,2024 Issue 3
      专题研究
    • LI Ming-ze, QIN Yu-long, LI Zheng, XU Yun-feng, WU Wen-hui, LIU Wei, YE Ya-kang, ZHOU Xiong

      2018,37(3):366-378, DOI:

      Abstract:

      This paper discusses the petrogenesis of the two-mica granite and its genetic relationship with pegmatite in Jiajika area, west Sichuan Province, by detailed field investigation and laboratory analysis. The whole rock analytical results show that SiO2 content of two-mica granite is 73.93%~75.06%, and total alkali is 7.90%~8.36% with high concentration of K, suggesting high-K calc-alkaline series; the content of Al2O3 is 14.24%~14.77%, and A/CNK=1.14~1.24, implying strong peraluminous S type granite; ΣREE=31.18×10-6~41.67×10-6,LREE/HREE=4.15~6.41,δEu=0.46~0.70, and CaO/Na2O=0.07~0.12(<0.3),indicating that its source might have been pelite with rare content of psammite, and high ratio of Al2O3/TiO2 (133.1~279.8) implies that it is high-pressure-low-temperature post-collision granite. The SiO2 content of the granite pegmatite is 72.59%~80.91%, the total alkali is 5.26%~10.60%, Al2O3 is 11.79%~17.64%, σ=0.74~3.80; A/CNK=0.98~2.38; ΣREE=4.03×10-6~8.29×10-6, LREE/HREE=2.61~10.40, and δEu=0.18~0.68. There are considerable differences between two-mica granite and granite pegmatite in the aspect of the content of major and trace elements. And there is close genetic relationship between granite and pegmatite in the area. Magma immiscibility might be the key factor for the formation of (ore-bearing) granite pegmatite. The pegmatite melt riched in volatile components might be separated during the upwelling of granite magma and metasomatized minerals in wall rock to further concentrate rare metal elements during its migration. The difference between two-mica granite and pegmatite might cause the apparent differences in REEs and elements such as Th, Sr, Ti, Y, Rb and Nb. The different characteristics of pathways and environments that the pegmatite melt passed and emplaced might have resulted in element concentration variance in different sites. In comparison with two-mica granite, there existed a certain degree of jumping characteristic during the formation and evolution of the pegmatite in Jiajika area.

    • 宝玉石矿物学
    • GAN Yuan-lu, WANG Chao-wen, LEI Xin-rong, LI Zhuo-yang, WANG Hui-ning, ZHANG Yun-yun, LI Yi-long

      2015,34(3):418-426, DOI:

      Abstract:

      Guilin Chicken Blood Red Jasper (CBRJ) is a kind of quartz jasper. It is characterized by bright red to black colors and high hardness. However, few researches have been focused on the field occurrence, geological background, rock structure and genesis of its color. Field surveys indicate that the Guilin CBRJ is hosted in low-grade metamorphic sandstones which experienced vapor-water hydrothermal metamorphism and iron oxide dissemination. It occurs in the Sanmenjie Formation of Neoproterozoic Danzhou Group in Longsheng area in the north of Guangxi. Tectonically, the ore deposit of Guilin CBRJ is located at the juncture of Yangtze and Cathaysian plates, which has undergone a complex geological process. Its formation was related to multi-phase tectono-magmatic activities from Neoproterozoic to Triassic. Detailed analyses of mineralogy, micro-texture and geochemical composition of Guilin CBRJ were carried out by polarizing microscope, X-ray diffraction, and electronic microprobe. The results indicate that the CBRJ is mainly composed of quartz and hematite, with dolomites in some samples. Quartz grains exhibit two types of allotriomorphic equigranular texture and idiomorphic porphyroblastic texture. The latter one, in which distinct enlargement texture can be observed, reveals a metasomatic metamorphism phase. Hematite occurs in three types: ① single crystal existent between or inside the quartz particles, ② dusty crystals wrapped in the quartz particles, and ③ disseminated crystals filled between the quartz particles. The Fe3+ in the hematite should be responsible for the color of the CBRJ. Electron microprobe analysis shows that the hematites of single crystal and disseminated crystals have 78.9%~85.6% iron oxides, but the dusty crystal is too small to be analyzed. In combination with the different generations of quartz and hematite, the authors have reached the conclusion that the formation of different types of these minerals in the Guilin CBRJ was consistent with the regionally geological evolution in this area.

    • 专题研究
    • ZHANG Li-cheng, WANG Yi-tian, CHEN Xue-feng, MA Shi-qing, WANG Zhi-hua, YU Chang-fa

      2013,32(4):431-449, DOI:

      Abstract:

      The Hongyuntan iron deposit is hosted in pyroclastic rocks of the Lower Carboniferous Yamansu Formation. The ore bodies occur as layers, stratoid bodies or lenses. The principal ore mineral is magnetite, together with minor maghemite, specularite, pyrite and trace chalcopyrite. The gangue minerals include garnet, diopside, actinolite, chlorite, tremolite, epidote, biotite, albite and quartz. The ore structures are mainly of massive and disseminated forms, with occasional banded or veined forms. The ore textures are of subhedral-anhedral granular and metasomatic types. The wall rock alteration shows symmetrical zoning, and the alteration colors change from dark to light from ore bodies outwards. On the basis of observed mineral assemblages and ore fabrics, two periods of ore deposition were recognized, i.e., skarn period and hydrothermal ore-forming period, which could be further subdivided into four metallogenic stages, namely skarn stage, retrograde alteration stage (main ore-forming stage), early hydrothermal stage and quartz-sulfide stage. Electron microprobe analyses show that the end member of garnet is mainly andradite-grossularite. The composition of pyroxene is mainly diopside-asteroite. The amphiboles is composed mainly of actinolite and tremolite with minor magnesiohornblende. The composition of these skarn minerals suggests that skarn in the Hongyuntan iron deposit is calcic skarn, belonging to metasomatic skarn. The characteristics of main and trace elements suggest that the formation of magnetite was closely related to the skarn. In combination with geological characteristics, the authors suggest that the skarn might have resulted from interaction between Ca-rich pyroclastic and Fe-rich magmatic hydrothermal fluid which was transported along the fault system. The formation of magnetite was hence related to the regressive metamorphism of the skarn.

    • 综合资料
    • SHEN Qi-han

      2009,28(5):495-500, DOI:

      Abstract:

      This paper has mainly recommended a mineral abbreviation list (see Table 2 and Table 3). Table 2, which contains 243 minerals, was compiled by IUGS Subcommittee on the Systematic of Metamorphic Rocks (SCMR) in 2007. The author selected other 29 minerals and, on such a basis, formulated Table 3. Thus, the total mineral abbreviations come to 272. It is hoped that they can be popularized in future and become more and more perfect through utilization, so as to provide a basis for ultimate standardization and unification.

    • Gan Guoliang Yichang Institute of Geology, Mineral Resources, Chinese Academy of Geological Sciences Department of Grologicol, Atmospheric Sciences, lows State Univeraity, Ames, IAS0011, U.S.A

      1993,12(2):144-181, DOI:

      Abstract:

      This paper presents partition coefficients of 69 chemical elements (Li, Rb,Cs, K, Na, Ca, Ba, Sr, Mn, Fe, Mg, Cu, Pb, Zn, Co, Ni, Be, La, Ce, Nd,Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc, Cr, In, Ga, Al, B,Cd, Sb, Bi, U, Th, Zr, Hf, Si, Ti, Ge, Sn, Mo, Nb, Ta, W, V, P, F, Cl,S, N, O, C, As, Pu, Re, Os, He, Ne, Ar, Kr and Xe) and the univalent radical (OH) in 28 minerals (olivine, clinopyroxene, orthopyroxene, amphibole,biotite, Phlogopite, plagiocla-se, K--feldspar, quartz, magnetite, ilmenite, garnet,zircon, apatite, allanite, topaz, sphene, cordierite, hauyne, leucite, nepheline,whit-lockite, brookite, petovskite, melilite, armalcolite, spinel and rutile) from 8 types of rocks, namely metaluminous (ultra) basic rock, peralkaline (ultra) basic rock, metaluminous intermediate rock, peralkaline intermediate rock,metaluminous acid rock, peralkaline acid rock, peraluminous acid rock and ultra-acid rock. It is found through an integrated ahalysis and comparison that the composition and structure of minnerals and melts seem to be the most important factors controlling mineral-melt element partitioning. Importanceshould be attached to minral structure and Al-supersaturation of melt which have, not been discussed by research workers. Finally, the present state and theproblems to be solved in the study of mineral--melt element partition coefficients are analysed, and the future trends of this research field are predibted.

    • 综合资料
    • ZHANG Xi-huan, REN Yu-feng

      2008,27(2):135-151, DOI:

      Abstract:

      本文以表格的形式列举了经国际矿物学协会(IMA)新矿物与矿物命名委员会(CNMMN)批准、并于2003年度正式发表的新矿物共55种,其中硅酸盐31种,磷酸盐5种,砷酸盐2种,硫酸盐4种,硫化物3种,碳酸盐2种,钒酸盐2种,硼酸盐1种,硒化物1种,硫盐1种,氧化物1种,氢氧化物1种,复杂卤化物1种.文中表格依次列出了矿物的中外文名称及化学式、晶系及晶胞参数、主要粉晶数据、物理性质、光学性质、产状及共生(伴生)组合等.

    • 方法与应用
    • XU Jie, ZHANG Gui-bin, LI Nan, LIN Meng, WANG Jia-xing

      2020,39(3):323-334, DOI:

      Abstract:

      The combination of multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) and laser ablation provides a useful tool for tracing the geological process by analyzing minerals under microscales. As one of the non-traditional stable isotopes, boron isotope has attracted more and more attention. In this study, the authors developed an in-situ method for high-precision analysis of B isotope in tourmaline with high-content boron and muscovite with low-content boron. Tourmaline and glass reference materials were applied to correcting the mass fractionation respectively, and in-situ B isotopes of two natural samples from southwestern Tianshan were also tested. In addition, the boron isotope of the in-house standard T-PKU was calibrated as -13.07‰±0.42‰ (2SD, n=66). The above testing results reveal that the condition of LA-MC-ICPMS is stable for a long term and suitable to producing high quality data about tourmaline with minimum spot size of 10 μm and muscovite with > 20×10-6 B concentration. The B isotopes of tourmaline and paragonite in Tianshan samples are helpful for tracing fluids sources.

    • 宝玉石矿物学
    • YAN Ruogu, QIU Zhili, DONG Chuanwan, LI Liufen

      2009,28(3):292-298, DOI:

      Abstract:

      High grade black jadeite is a kind of upscale and fashionable jade material that has become one of the jadeites characterized by fastest growing values in the past 20 years. Based on a comparison of mineralogical and geochemical characteristics between black jadeites (inky black jades)from different producing areas of the world, the authors hold that the black jadeites currently on the market can be mainly classified into jadeite jade, omphacitic jadeite jade and hornblende jade whose main components are jadeite, omphacite and dark green hornblende respectively. They include black chicken jade, ink jadeite and black kosmochlor from Myanmar and jade negro and galactic gold from Guatemala, with black chicken jades similar to those from Myanmar also seen in Japan and Kazakhstan. The research results suggest that the main mineral composition, jade structure and inclusion characteristic combinations of black jadeite jades from different producing areas have their respective typomorphic natures, which can be used as the distinctive characteristics for their sources.

    • 专题研究
    • HE Shi-ping, WANG Hong-liang, XU Xue-yi, ZHANG Hong-fei, REN Guang-ming

      2007,26(4):295-309, DOI:

      Abstract:

      Early Paleozoic volcanic rocks in Tianshui and Baoji areas along the eastern segment of North Qilian orogenic belt consists of Hongtubu basaltic lavas and Chenjiahe intermediate-acid volcanic rocks. Geochemical analyses show that Hongtubu basaltic lavas are similar to the intercalated basalts in Chenjiahe intermediate-acid volcanic rocks in characteristics, both fallen in the tholeiite series with high TiO2 (1.50%~2.73%). Their∑REE are 65.97×10-6~133.46×10-6 and 78.04×10-6~175.55×10-6 respectively, both are slightly enriched in LREE [(La/YbN being 2.00~4.40 and 2.71~4.40 respectively],and both have no obvious Eu anomaly or weak Eu negative anomaly(δEu being 0.85~1.10 and 0.85~0.99 respectively). Basalts from two groups are typically characterized by selected enrichment of LILEs, low abundances of HFSEs relative to NMORB, and prominent troughs of Nb and Ta, with low Nb/La ratio(0.28~0.43), which indicates the affinity of these volcanic rocks to island arc tholeiite(IAT). In addition, εNd(t)(+2.22~+4.08)values of basalts suggest that their mantle sources are similar to the depleted mantle source. Zr/Nb=17.21~36.33 and Ce/Nb=5.73~8.17, implying geochemical characteristics of N-MORB. Sr, Nd and Pb isotopes from Hongtubu basalts are similar to those in Chenjiahe basalts in composition. In the diagrams of εNd(t)-(87Sr/86Sr)t, (207Pb/204Pb)t-(206Pb/204Pb)t,(87Sr/86Sr)t-(206Pb/204Pb)t and εNd(t)-(206Pb/204Pb)t for basalts, the data are fallen in the DM, EMⅠand EMⅡ areas, probably with a little crustalontamination, indicating that the magma of basalts might have had a mixed gin.Thentermediate-acid volcanic rocks from Chenjiahe belong to the calc-alkaline series,they have relatively high abundances of REE∑REE=127.51×10-6~276.01×10-6), and are significantly enriched in LREE[(La/YbN= 4.79~13.51]. Most intermediate-acid volcanic rocks show weak Eu negative anomaly (δEu=0.53~1.20). The trace element patterns of Chenjiahe acid volcanic rocks are similar to those of the ocean ridge granite (ORG), with marked troughs of Nb, Ta, Zr and Hf. A synthetic study shows that the Chenjiahe intermediate-acid volcanic rocks in the eastern segment of North Qilian orogenic belt were formed in an island-arc setting, whereas the Hongtubu basalts were formed in an intra-arc rift setting (or an initial back-arc basin setting), probably being products of the early spreading evolution of the island_arc system towards the back-arc basin in the eastern segment of North Qilian during late Early Paleozoic. The results obtained provide evidence for the existence of the trench-arc-basin system at the juncture of Qilian and North Qinling orogenic belts.

    • 环境矿物学
    • XING Run-hua, SUI Xin-xin

      2022,41(1):185-194, DOI:

      Abstract:

      The geochemical characteristics and abnormal sources of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in the soil of Southern Xuancheng were analyzed and studied by using the 1:250 000 land quality geochemical survey data. It is found that the geological background is the main controlling factor for the content of soil elements, and that the spatial distribution characteristics of heavy metal elements in the surface and deep soil in the area are significantly consistent with the geological background and sedimentary environment. The high content of heavy metal in the soil parent rock geological background (Hetang Formation, Piyuancun Formation and Lantian Formation, etc) is the main influencing factor for the high anomaly of soil heavy metal elements. In addition, mining and atmospheric dry and wet deposition are also one of the factors affecting high anomaly of heavy metals in soil. It is found that Pb, Hg, Cd and Cr in soil have input sources of atmospheric dry and wet deposition. The main impact index of heavy metal in soil pollution risk in the survey areas was Cd. The proportion of samples that soil Cd exceeded the control value of soil pollution risk of agricultural land was 2.56%. The morphological analysis results show that soil Cd is mainly in ion-exchange state. Combined with crops investigation, it is found that there is a certain ecological risk in the area with high abnormal soil Cd.

    • 专题研究
    • LIN Bin, TANG Ju-xing, ZHENG Wen-bao, LENG Qiu-feng, LIN Xin, WANG Yi-yun, MENG Zhan, TANG Pan, DING Shuai, XU Yun-feng, YUAN Mei

      2016,35(3):391-406, DOI:

      Abstract:

      The Cuonadong leucogranite is one of the most important parts of North Himalayan leucogranite belt. Geochemical data show that Cuonadong leucogranite is the calcium alkaline and strong peraluminous granite with high silica (SiO2 is 74.20%~74.52%), poor iron (Fe2O3 is 0.04%~0.20%, FeO 0.04%~0.58%), poor magnesium (MgO is 0.06%~0.14%), and calcium alkaline (σ is 2.15~2.32) as well as strong peraluminous nature (A/CNK is 1.11~1.15). Its total rare earth is relatively low (∑REE is 47.24×10-6~57.59×10-6), with enrichment of LREE (LREE is 39.85×10-6~49.23×10-6), depletion of HREE (HREE is 6.91×10-6~8.68×10-6) and obvious negative Eu anomaly (0.49~0.80). It is characterized by an enrichment of some large ion lithophile elements (Rb, Th, U, K) and loss of high field strength elements (Nb, Ta, Zr Ti). Zircon U-Pb dating results show that the Cuonadong leucogranite's formation time is Miocene (21 Ma), which belongs to the peak of the late stage of north Himalayan leucogranite (24~12 Ma). Zircon εHf(t) values are negative with a wide variation (-3.92~-17.64), which shows that its magma source was the crust, mostly from the metapelite, with the probable mixing of many kinds of materials in its source. The petrogenesis of Cuonadong leucogranite is that the high Himalayan crystalline rock series experienced decompression melting during the rapid pull-back of the plate in the post-collision tectonic setting, with the initial magma crystallization temperature being 675~702℃.

    • PAN Rong-hao, ZHU Lei, WANG Si-jia, WANG Ji-chen, WU Jia-yi, HOU Tong

      2022,41(3):519-536, DOI:

      Abstract:

      Quantitatively determining the timescale during mantle-derived magma ascent from the source to eruption or emplacement is essential for the understanding of magmatism, however, the timescales of eruption/emplacement are still poorly constrained. Shanxi Datong Cenozoic volcanic field, north of the North China Craton, is an ideal area for the investigation. In this study, we focused on the mantle olivine xenocrysts entrained in ca. 0.2 Ma Shenquansi alkali basalt, and its timescale of residence in the host magma prior to eruption. According to mineral chemistry, cores of these mantle olivine xenocrysts have Fo values up to 97.7, which can be defined as extremely magnesian olivine. They are also characterized by the extremely low contents in Ca, Mn and Ni, suggesting they were captured from metasomatized mantle peridotite. Moreover, both of the mantle olivine xenocrysts display complex CaO profiles, attributed to complex magmatic processes in the magma plumbing system. The reaction rim widths of one olivine xenocryst vary significantly, implying it has experienced multiple crack processes when captured or dur- ing transport. The Fo values of the mantle olivine xenocrysts rims are about 70, indicating they are in diffusion equilibrium with the host magma (alkali basalt) at rims. Timescales obtained by Fe-Mg diffusion chronometry of olivine mantle xenocrysts show that they have only resided in the magma for months. For a lithospheric mantle thickness of 40~70 km, the fastest average ascent rate may exceed 500 m/d.

    • CAO Guang-yue, XUE Huai-min, WANG Jin-guang

      2014,33(6):1019-1038, DOI:

      Abstract:

      In this paper,LA-ICP-MS zircon U-Pb dating was carried out for four samples of volcanic rocks from Qingshan Group in Jiaodong area and, as a result, their concordant ages were obtained, which are 119.4±0.9 Ma, 118.2±1.0 Ma,120.2±0.9 Ma and 120.0±0.8 Ma, respectively. The results show that all the volcanic rocks in Jiaodong area were formed from about 120 Ma to 118 Ma in the Early Cretaceous period. The ages of Qingshan Group volcanic rocks from Shandong Province controlled by Tan-Lu fault are similar to those from the Su-Wan segment of the Tan-Lu fault zone,but younger than those around the Tan-Lu fault zone,which indicates that the duration of volcanic eruption along Tan-Lu fault is probably longer than the duration in other areas under the background of lithospheric thinning in eastern China. Geochemically, all the intermediate and acidic volcanic rocks have high K2O, ALK, LREE values and low MgO, TiO2, Ni, Cr, HREE values. According to the geochemical features, the volcanic rocks can be subdivided into trachyte-trachydacite and rhyolite. The trachyte-trachydacite is characterized by LILE enrichment(Rb,Ba,K)and HFSE depletion(Nb,Ta,Ti,P), but the rhyolite exhibits stronger depletion of Ba,Sr and HFSE (Ti,P). Compared with the rhyolite,the trachyte-trachydacite possesses higher Sr and Ba values as well as La/Nb and Ba/Nb ratios,but lower Rb/Ba ratios and δEu values. All these data indicate that they might have been derived from different magma sources. It is inferred that the trachyte-trachydacite rocks were derived from the mixture of the partial melting of the lower crust(Yangtze Craton or North China Craton)and enriched lithospheric mantle. In addition, the rhyolites were related to the partial melting of the lower crust in the regional extension environment and high geothermal anomaly background with crystallization differentiation during the magma evolution.

    • 综述与进展
    • ZHANG Wei

      2014,33(4):747-762, DOI:

      Abstract:

      Cordierite is a mineral material characterized by low thermal expansion coefficient and good thermal shock resistance. Cordierite mineral material is relatively rare in nature, so cordierite is synthesized usually by the method of artificial synthesis. Based on the newest investigation results of synthetic cordierite, this paper deals with the progress of researches on such synthesis methods of cordierite as high purity oxide solid reaction at high temperature, natural mineral solid reaction at high temperature, the utilization of industrial wasted materials, the employment of agricultural wasted materials, the sol-gel and the low-temperature combustion synthesis. At present, the method of natural mineral solid reaction at high temperature is used for the preparation of cordierite in industry. In spite of a lot of advantages, this method also has many disadvantages. Therefore, the development trend of cordierite synthesis seems to solve the problem as to how to apply other synthesis methods to industrial preparation.

    • 宝玉石矿物学
    • GUO Li-he, HAN Jing-yi, LUO Hong-yu

      2006,25(4):349-356, DOI:

      Abstract:

      At present, the infrared transmission spectroscopy is the best technique for determining whether jadeite is polymer-impregnated or not, and the infrared reflectance spectroscopy is a nondestructive and rapid determination method that provides mainly the fundamental frequency vibration spectra data of minerals and shows new application potentials in gemological research, especially in the identification of gem species. The gemological application of IR reflectance spectroscopy and the identification system of IR spectra of gems, including a database of 318 spectra and a searching and identifying program, are described in this paper.

    • 专题研究
    • LIN Guang-chun

      2013,32(4):485-495, DOI:

      Abstract:

      Petrology, geochemical and Nd isotopic data are reported for the Neoproterozoic Danba metabasalt in the Kangdian Rift on the western margin of the Yangtze block. Samples were collected from alkaline basalts, which are enriched in MgO, TiO2, with Mg# being 0.51~0.59. They have high total rare earth elements and show high fractionation between LREE and HREE. The trace elements are characterized obviously by enrichment of Th, Nb, Ta, Zr, Hf and LREE but depletion of Y and HREE. Their geochemical and Nd isotopic characteristics suggest that they are similar to OIB. The basaltic magma was generated in an intraplate setting, and was generated by partial melting of OIB mantle source region, with variable degrees of contamination of SCLM during magma ascending; in addition, some samples might have experienced contamination of the lower crust. These samples reveal some plume magmatism characteristics in petrochemistry, and imply that magmatism was probably related to the Neoproterozoic plume event, which resulted in the breakup of Rodinia supercontinent.

    • ZHANG Kan, ZHU Xiang-kun

      2013,32(4):529-537, DOI:

      Abstract:

      The newly-exposed lower strata of the Xiamaling Formation near Tielingzi Village in Jixian County contain rich siderites. This paper reports the basic geological characteristics of these siderite-rich strata in terms of the field outcrop, petrology and major elements. Studies show that the profile is characterized by black shale interbedded with silty iron-rich layers/siderite concrete layers, and also has minor siltstone. Some iron-rich strata have turned into limonite layers in the outcrop because of intense weathering. Siderite is the main iron mineral phase in the strata. Siderites can form iron concretes, showing micritic or microcrystalline granulitic textures under the microscope, or form silty ferruginous layers with almost a comparable amount of silty quartz; it can also distributed sporadically in siltstone and black shale with relatively coarse particles. There also exists very little siderite residue in weathered limonite layers. The overall features of major elements show that the strata are rich in SiO2, TFe and TOC, but poor in MnO, CaO, MgO, P2O5 and S. Except for ferriciron in weathered layers, there is mainly ferrous iron in the strata. The TOC content decreases in order of siderite concrete, silty iron-rich layer, black shale and siltstone. The correlation diagram between TFe and Al2O3 content shows a negative correlation in iron-rich layers, while a positive correlation between them exists in normal black shale and siltstone, which suggests that iron in the former form originated from the ocean itself, while iron in the latter form originated mainly from terrigenous detritus. In addition, FeO content has a positive correlation with TOC content in fresh samples, which implies that the genesis of siderites may have some relationship with organic matter.

    • 其他
    • LUO Yue-ping, DENG Wang-hui, DUAN Ti-yu, WANG Chun-sheng

      2011,30(Z1):181-186, DOI:

      Abstract:

      As more and more treated turquoises appear on Chinese gem market, the authors collected lots of turquoises from different deposits on Chinese gem market in order to sum up the characteristics of the natural turquoises on Chinese gem market. At the same time, different types of treated turquoises were studied to find general difference between them and natural turquoises. The results show that natural turquoise and treated turquoise have different shades of color, inclusions and appearances. IR spectra of both natural and treated turquoises were studied, indicating that there are absorption peaks at 1 735, 1 600 and 1?500 cm-1 in treated turquoises, which are caused by the man-made polymer. If the turquoise is treated by polymer, there are absorption peaks at 1 735, 1 600 and1 500 cm-1 in a turquoise, and this can serve as convincing evidence in this aspect.

    • Zhou Zheng

      1997,16(1):81-90, DOI:

      Abstract:

      From the discovery of the first new mineral hsianghualite in 1958 to the end of 1995,74 new minerals found in China had been approved by IMA CNMMN. Among them, 2/3 were discovered after 1981. The discovery of new minerals in China has the following features:(1) With the development of analytical methods, the number of new minerals discovered per year increases gradually: from the end of 1950s to 1960s, only one new mineral was discovered every year on the average, whereas from 1980s till now, three new minerals were discovered averagely every year. (2) The structures of many new minerals have been determined. (3) Most of the new minerals are in the lower category, mainly in the monoclinic system, and perfect crystals are rare; hsianghualite has the most abundant crystal faces, whose ideal faces can reach 146. (4) Among those new minerals, silicates take the first place in number, followed by native elements, alloys, and then oxides. (5) The modes of occurrence of new minerals are varied, most of them occurring in oxidized zones of various deposits and deposits related to ma fic or ultramafic rock masses. There are a few new minerals occurring in skarn and placer deposits or even in cosmic dusts and meteorite.(6) The new minerals are characterized by wide but uneven distribution. Till now, new minerals have been discovered in 20 provinces or autonomous regions, especially in Hebei, Qinghai, Inner Mongolia and Henan. The number of new minerals found in North China is larger than that found in South Chine. (7) The number of discoverers of new minerals is in tens. The first discoverer of new mineral is Prof. Huang Yunhui, whereas Prof. Yu Zuxiang is the one who discovered the most numerous new minerals in China, totally disclosing 11 new minerals by himself or together with other experts. Most of the discoverers are members of the Chinese Academy of Geological Sciences, China University of Geosciences, and Institute of Geochemistry, Academia Sinica as well as other educational and scientific research institutions. The discovery of new minerals has promoted the development of mineralogy in China. Tens of discoverers were awardees of the National Natural Sciences Prize or the Science and Technology Progress Prize of the Ministry of Geology and Mineral Resources for the discovery and research results of new minerals in 1980s. More than 60 new mineals discovered in China were collected by the Geological Museum of China, with some of them exhibited in the Minerals and Rocks Exhibiting Room.

    • TAO Ji_xiong 1, HU Feng_xiang 1, CHEN Zhi_yong 1, 2

      2003,22(2):112-118, DOI:

      Abstract:

      Indosinian S-type granites are widely distributed in central Inner Mongolia on the northern margin of North China landmass. Spread in nearly EW direction, the granites have formed a gigantic compound granite belt, with porphyritic biotite-admellite and moyite being the two main types. SiO2is abundant, Al2O3is 12.38%~15.34%. A/NKC (molecule ratio)>1.1, K2O/Na2O=1.1~3.1,δ=1.9~2.6,ΣREE is 45.778 ×10-6~486.501×10-6, andδEu=0.1~0.8. A series of zircon U-Pb surface ages (207~227 Ma) for the granites have been recently obtained from 1/50 000 regional geological survey. As the lithofacies and geochemical characteristics of the granites are similar to those of S-type granites, the authors conclude that the Indosinian granite in this area was formed in a post-collision setting instead of in the setting of syn-collision between North China plate and Siberia plate.

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    Editor:Zengqian Hou

    ISSN 1000-6524

    CN 11-1966/P