2023 Vol.6(1)

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Original Articles
Characteristics of B, Zn and Se in stream sediments of Tanzania and their agricultural applications: Based on 1∶1000000 geochemical survey
Kang-kang Xu, Hong-wei Sun, Wei Xie, Fu-qing He, Xiao-yang Liu, Kai Sun, Sheng-fei He, Xing-yuan Wu, Peng-hui Gong, Godfrey Machumu
2023, 6(1): 1-14. doi: 10.31035/cg2022049
[Abstract](3401) [FullText HTML] (2361) [PDF 16955KB](126)
Tanzania is located in eastern Africa with a predominantly agricultural ecomomy, the potential for developing and utilizing cultivated land are promising, but scientific guidance is required. B, Zn and Se are essential micronutrients for plants and human body with crucial biological functions, in particular, Se is significant for human health and considered as “the king of anti-cancer”. As these elements required by human or plants are mainly absorbed from soil directly or indirectly, therefore, it is important to understand the contents and distributions of them in the soil of cultivated land for guiding agricultural production. In this work, low-density geochemical survey at the scale of 1∶1000000 was carried out in Tanzania, and the results show that the concentrations of B, Zn and Se in stream sediments are low and their distributions are heterogeneous. According to the distributions of geological units, the existing cultivated land resources can be divided into five regions in Tanzania. Compared with the national background values, the concentrations of B, Zn and Se are insufficient overall but enriched locally in these regions. In general, element concentrations in stream sediments and soil have a positive correlation because of their similar sources, which is essential in agriculture application. Based on the information provided by low-density geochemical data and maps, the Se-sufficient and Se-rich regions were delineated in Tanzania, where can be used to develop Se-rich industries. Finally, this paper believes that geochemical survey is a powerful tool for cultivated land evaluation, agriculture management and land development.
Ecological risk assessment and early warning of heavy metal cumulation in the soils near the Luanchuan molybdenum polymetallic mine concentration area, Henan Province, central China
Zhen-yu Chen, Yuan-yi Zhao, Dan-li Chen, Hai-tao Huang, Yu Zhao, Yu-jing Wu
2023, 6(1): 15-26. doi: 10.31035/cg2023003
[Abstract](2048) [FullText HTML] (1500) [PDF 2063KB](92)
The Luanchuan molybdenum polymetallic mine concentration area is rich in mineral resources and has a long history of mining. The environmental impact of long-term mining activities cannot be ignored. It is of great significance to study the ecological risk and the accumulation trends of heavy metals in the soil of mining areas for scientific prevention and control of heavy metal pollution. Taking the Taowanbeigou River Basin in the mine concentration area as the research object, the ecological pollution risk and cumulative effect of heavy metals in the soil of the basin were studied by using the comprehensive pollution index method, potential ecological risk assessment method and geoaccumulation index method. On this basis, the cumulative exceeding years of specific heavy metals were predicted by using the early warning model. The comprehensive potential ecological risk of heavy metals in the soil near the Luanchuan mine concentration area is moderate, and the single element Cd is the main ecological risk factor, with a contribution rate of 53.6%. The overall cumulative degrees of Cu and Pb in the soil are “none-moderate”, Zn and Cd are moderate, Mo has reached an extremely strong cumulative level, Hg, As and Cr risks are not obvious, and the overall cumulative risks order is Mo>Cd>Zn>Cu>Pb>Hg. According to the current accumulation rate and taking the risk screening values for soil contamination of agricultural land as the reference standard, the locations over standard rates of Cu, Zn and Cd will exceed 78% in 90 years, and the over standard rate of Pb will reach approximately 57% in 200 years. The cumulative exceeding standard periods of As, Cr and Hg are generally long, which basically indicates that these elements do not pose a significant potential threat to the ecological environment. Mining activities will accelerate the accumulation of heavy metals in soil. With the continuous development of mining activities, the potential pollution risk of heavy metals in the soil of mining areas will also increase.
Passability test and simulation of sand control string with natural gas hydrates completion in large curvature hole
Hao-xian Shi, Yan-jiang Yu, Ru-lei Qin, Jun-yu Deng, Yi-xin Zhong, Li-qiang Qi, Bin Li, Bo Fan, Qiu-ping Lu, Jian Wang, Kui-wei Li, Ye-cheng Gan, Gen-long Chen, Hao-wen Chen, Zhi-ming Wu
2023, 6(1): 27-36. doi: 10.31035/cg2022024
[Abstract](5043) [FullText HTML] (2683) [PDF 4853KB](35)
To meet the requirements of marine natural gas hydrate exploitation, it is necessary to improve the penetration of completion sand control string in the large curvature borehole. In this study, large curvature test wells were selected to carry out the running test of sand control string with pre-packed screen. Meanwhile, the running simulation was performed by using the Landmark software. The results show that the sand control packer and screen can be run smoothly in the wellbore with a dogleg angle of more than 20°/30 m and keep the structure stable. Additionally, the comprehensive friction coefficient is 0.4, under which and the simulation shows that the sand control string for hydrate exploitation can be run smoothly. These findings have important guiding significance for running the completion sand control string in natural gas hydrate exploitation.
Application of tensor CSAMT with high-power orthogonal signal sources in Jiama porphyry copper deposit, South Tibet
Peng-liang Yu, Ting Qu, Ri-zheng He, Jian-li Liu, Su-fen Wang, Xiao-long Chen
2023, 6(1): 37-49. doi: 10.31035/cg2021065
[Abstract](5444) [FullText HTML] (2928) [PDF 5306KB](66)
The Jiama porphyry copper deposit in Tibet is one of the proven supergiant copper deposits in the Qinghai-Tibet Plateau at present, with the reserves of geological resources equivalent to nearly 20×106 t. However, it features wavy and steep terrain, leading to extremely difficult field operation and heavy interference. This study attempts to determine the effects of the tensor controlled-source audio-magnetotellurics (CSAMT) with high-power orthogonal signal sources (also referred to as the high-power tensor CSAMT) when it is applied to the deep geophysical exploration in plateaus with complex terrain and mining areas with strong interference. The test results show that the high current provided by the high-power tensor CSAMT not only greatly improved the signal-to-noise ratio but also guaranteed that effective signals were received in the case of a long transmitter-receiver distance. Meanwhile, the tensor data better described the anisotropy of deep geologic bodies. In addition, the tests also show that when the transmitting current reaches 60 A, it is still guaranteed that strong enough signals can be received in the case of the transmitter-receiver distance of about 25 km, sounding curves show no near field effect, and effective exploration depth can reach 3 km. The 2D inversion results are roughly consistent with drilling results, indicating that the high-power tensor CSAMT can be used to achieve nearly actual characteristics of underground electrical structures. Therefore, this method has great potential for application in deep geophysical exploration in plateaus and mining areas with complex terrain and strong interference, respectively. This study not only serves as important guidance on the prospecting in the Qinghai-Tibet Plateau but also can be used as positive references for deep mineral exploration in other areas.
Response to the Lomagundi-Jatuli Event in the southwestern margin of the Yangtze Plate: Evidence from the carbon and oxygen isotopes of the Paleoproterozoic Yongjingshao Formation
Jun-ping Liu, Wei Yin, Shi-pan Yang, Jiang-tai Zhao, Wen-tao Zeng, Feng Tang, Shi-jun He, Wei-ke Li
2023, 6(1): 50-60. doi: 10.31035/cg2022033
[Abstract](5210) [FullText HTML] (2710) [PDF 6162KB](89)
The Lomagundi-Jatuli Event (LJE) refers to the significant positive carbon isotope excursion in seawater constituents that occurred immediately after the increase in atmospheric oxygen content during the Paleoproterozoic (2.22‒2.06 Ga). The δ13C values of 46 dolostone samples collected from the Paleoproterozoic Yongjingshao Formation varied in the range of 0.05‰‒4.95‰ (V-PDB; maximum: 4.95‰) in this study, which may be related to the multicellular eukaryotes in the Liangshan Formation in the Yimen Group. They are much higher than the δ13C values of marine carbonates (−1.16‰ on average). The δ13C values of other formations in the Paleoproterozoic Yimen Group are negative. The notable positive carbon isotope anomalies of the Yongjingshao Formation indicate the response to the LJE at the southwestern margin of the Yangtze Block, which is reported for the first time. Furthermore, they are comparable to the δ13C values of carbonates in the Dashiling Formation of the Hutuo Group in the Wutaishan area in the North China Craton, the Wuzhiling Formation of the Songshan Group in the Xiong’er area, Henan Province, and the Dashiqiao Formation of the Liaohe Group in the Guanmenshan area, Liaoning Province. Therefore, it can be further concluded that the LJE is a global event. This study reveals that LJE occurred in Central Yunnan at 2.15‒2.10 Ga, lasting for about 50 Ma. The macro-columnar, bean-shaped, and microfilament fossils and reticular ultramicrofossils of multicellular eukaryotes in this period were discovered in the Liangshan Formation of the Yimen Group. They are the direct cause for the LJE and are also the oldest paleontological fossils ever found. The major events successively occurring in the early stage of the Earth include the Great Oxygenation Event (first occurrence), the global Superior-type banded iron formations (BIFs), the Huronian glaciation, the Great Oxygenation Event (second occurrence), the explosion of multicellular eukaryotes, the positive carbon isotope excursion, and the global anoxic and selenium-rich sedimentary event. The authors think that the North China Craton and the Yangtze Craton were possibly in different tectonic locations of the same continental block during the Proterozoic.
Quantitative relationship between surface sedimentary diatoms and water depth in North-Central Bohai Bay, China
Zhi-wen Shang, Jian-fen Li, Holger Freund, Pei-xin Shi, Hong Wang
2023, 6(1): 61-69. doi: 10.31035/cg2022040
[Abstract](3248) [FullText HTML] (2179) [PDF 2257KB](43)
To study the quantitative relationship between surface sedimentary diatoms and water depth, 67 surface samples were collected for diatom analysis on eight profiles with water depth variation from the muddy intertidal zone to the shallow sea area in North-Central Bohai Bay, China. The results showed that the distribution of diatoms changed significantly in response to the change in water depth. Furthermore, the quantitative relationship between the distribution of dominant diatom species, their assemblages, and the water depth was established. The water depth optima for seven dominant species such as Cyclotella striata/stylorum, Paralia sulcata, and Coscinodiscus perforatus and the water depth indication range of seven diatom assemblages were obtained in the study area above the water depth (elevation) of 10 m. The quantitative relationship between surface sedimentary diatoms and water depth provides a proxy index for diatom-paleo-water depth reconstruction in the strata in Bohai Bay, China.
A comparative study of the main factors controlling geohazards induced by 10 strong earthquakes in Western China since the Wenchuan earthquake in 2008
Chao Peng, Zhi-qiang Yin, Xu-jiao Zhang, Hai Shao, Ming-fei Pang
2023, 6(1): 70-84. doi: 10.31035/cg2022009
[Abstract](5262) [FullText HTML] (2823) [PDF 15924KB](47)
Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response. By studying these factors, the geomorphic and geological factors controlling the nature, condition, and distribution of earthquake-induced geohazards can be analyzed. Such insights facilitate earthquake disaster prediction and emergency response planning. The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events, examining ten earthquakes including the Wenchuan, Yushu, Lushan events, to elucidate the main control factors of seismic geohazard. The authors observed that seismic geohazard occurrence is usually affected by many factors, among which active nature of the seismogenic fault, seismic peak ground acceleration (PGA), topographic slope and geomorphic height differences, and distance from the fault zone and river system are the most important. Compared with strike-slip earthquakes, thrust earthquakes induce more high-altitude and high-speed remote landslides, which can cause great harm. Slopes of 0°–40° are prone to secondary seismic geohazards, which are mainly concentrated 0–6 km from the river system. Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area. The maximum seismic PGA and secondary seismic geohazard number are positively correlated, and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation, respectively. Through the research, the spatial distribution of seismic geohazards is predicted, providing a basis for the formulation of emergency response plans following disasters.
Petrological and geochemical characteristics of mafic rocks from the Neoproterozoic Sugetbrak Formation in the northwestern Tarim Block, China
Hong-zhe Xie, Xiang-kun Zhu, Xun Wang, Yuan He, Wei-bing Shen
2023, 6(1): 85-99. doi: 10.31035/cg2021067
[Abstract](5228) [FullText HTML] (2908) [PDF 7734KB](123)
The Neoproterozoic Sugetbrak Formation in the Aksu area, which is located at the northwest margin of Tarim Block, comprises mafic rocks and provides key records of the evolution of the Rodinia supercontinent. However, the genetic relationship among these mafic rocks exposed in different geographical sections are still unclear. In this study, the petrology, geochemistry, and Sr-Nd-Pb isotope geochemistry of the mafic rocks exposed in the Aksu-Wushi and Yuermeinark areas have been studied in some detail along three sections. The authors found that the mafic rocks in these three typical sections were mainly composed of pyroxene and plagioclase, containing a small amount of Fe-Ti oxides and with typical diabasic textures. All the mafic rocks in this region also showed similar geochemical compositions. They were characterised by high TiO2 contents (1.47%–3.59%) and low MgO (3.52%–7.88%), K2O (0.12%–1.21%). Large ionic lithophile elements (LILEs) (Rb, Sr, and Cs) were significantly depleted. Meanwhile, high field strength elements (HFSEs) were relatively enriched. In the samples, light rare earth elements (LREEs) were enriched, while heavy rare earth elements (HREEs) were depleted. Based on the Zr/Nb, Nb/Y, and Zr/TiO2 ratios, the Aksu mafic rocks belong to a series of sub-alkaline and alkaline transitional rocks. The mafic rocks along the three typical sections showed similar initial values of 87Sr/86Sr (ISr) (0.7052–0.7097) and εNd(t) (–0.70 to –5.35), while the Pb isotopic compositions with 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb values of 16.908–17.982, 15.487–15.721, 37.276–38.603, respectively. Most of the samples plot into the area near EM-Ⅰ, indicating that the magma of the mafic rocks might have derived from a relatively enriched mantle with some crustal materials involved. The geochemical element characteristics of most samples showed typical OIB-type geochemical characteristics indicating that the source region had received metasomatism of recycled materials. Combining with the regional geological background and geochemical data, we inferred that the mafic rocks of the Sugetbrak Formation in the Aksu area were formed in an intraplate rift environment. Summarily, based on our study, the mafic rocks of the Sugetbrak Formation in the Aksu area were derived from a common enriched mantle source, and they were product of a magmatic event during the rift development period caused by the breakup of the Rodinia supercontinent.
Review Articles
Geology and mineralization of the Duobaoshan supergiant porphyry Cu-Au-Mo-Ag deposit (2.36 Mt) in Heilongjiang Province, China: A review
Sen Zhang, Nan Ju, Guo-bin Zhang, Yuan-dong Zhao, Yun-sheng Ren, Bao-shan Liu, Hui Wang, Rong-rong Guo, Qun Yang, Zhen-ming Sun, Feng-ming Xu, Ke-yong Wang, Yu-jie Hao
2023, 6(1): 100-136. doi: 10.31035/cg2023006
[Abstract](1746) [FullText HTML] (1391) [PDF 4960KB](49)
The reserves of the Duobaoshan porphyry Cu-Au-Mo-Ag deposit (also referred to as the Duobaoshan porphyry Cu deposit) ranks first among the copper deposits in China and 33rd among the porphyry copper deposits in the world. It has proven resources of copper (Cu), molybdenum (Mo), gold (Au), and silver (Ag) of 2.28×106 t, 80×103 t, 73 t, and 1046 t, respectively. The major characteristics of the Duobaoshan porphyry Cu deposit are as follows. It is located in a zone sandwiched by the Siberian, North China, and paleo-Pacific plates in an island arc tectonic setting and was formed by the Paleozoic mineralization and the Mesozoic mineralization induced by superposition and transformation. The metallogenic porphyries are the Middle Hercynian granodiorite porphyries. The alterations of surrounding rocks are distributed in a ring form. With silicified porphyries at the center, the alteration zones of K-feldspar, biotite, sericite, and propylite occur from inside to outside. This deposit is composed of 215 ore bodies (including 14 major ore bodies) in four mineralized zones. Ore body No. X in the No. 3 mineralized zone has the largest resource reserves, accounting for more than 78% of the total reserves of the deposit. Major ore components include Cu, Mo, Au, Ag, Se, and Ga, which have an average content of 0.46%, 0.015%, 0.16 g/t, 1.22 g/t, 0.0003%, and 0.001%‒0.003%, respectively. The ore minerals of this deposit primarily include pyrite, chalcopyrite, bornite, and molybdenite, followed by magnetite, hematite, rutile, gelenite, and sphalerite. The ore-forming fluids of this deposit were magmatic water in the early metallogenic stage and then the mixture of meteoric water and magmatic water at the late metallogenic stage. The ore-forming fluids experienced three stages. The ore-forming fluids of stage I had a hydrochemical type of H2O-CO2-NaCl, an ore-forming temperature of 375‒650°C, and ore-forming pressure of 110‒160 MPa. The ore-forming fluids of stage II had a hydrochemical type of H2O-CO2-NaCl, an ore-forming temperature of 310‒350°C, and ore-forming pressure of 58‒80 MPa. The ore-forming fluids of stage III had a hydrochemical type of NaCl-H2O, an ore-forming temperature of 210‒290°C, and ore-forming pressure of 5‒12 MPa. The Cu-Au-Mo-Ag mineralization mainly occurred at stages I and II, with the ore-forming materials having a mixed crust-mantle source. The Duobaoshan porphyry Cu deposit was formed in the initial subduction environment of the Paleo-Asian Ocean Plate during the Early Ordovician. Then, due to the closure of the Mongol-Okhotsk Ocean and the subduction and compression of the Paleo-Pacific Ocean, a composite orogenic metallogenic model of the deposit was formed. In other words, it is a porphyry - epithermal copper-gold polymetallic mineralization system of composite orogeny consisting of Paleozoic island arcs and Mesozoic orogeny and extension.
Lithium extraction from hard rock lithium ores (spodumene, lepidolite, zinnwaldite, petalite): Technology, resources, environment and cost
Tian-ming Gao, Na Fan, Wu Chen, Tao Dai
2023, 6(1): 137-153. doi: 10.31035/cg2022088
[Abstract](2481) [FullText HTML] (2382) [PDF 2512KB](154)
Lithium production in China mainly depends on hard rock lithium ores, which has a defect in resources, environment, and economy compared with extracting lithium from brine. This paper focuses on the research progress of extracting lithium from spodumene, lepidolite, petalite, and zinnwaldite by acid, alkali, salt roasting, and chlorination methods, and analyzes the resource intensity, environmental impact, and production cost of industrial lithium extraction from spodumene and lepidolite. It is found that the sulfuric acid method has a high lithium recovery rate, but with a complicated process and high energy consumption; alkali and chlorination methods can directly react with lithium ores, reducing energy consumption, but need to optimize reaction conditions and safety of equipment and operation; the salt roasting method has large material flux and high energy consumption, so require adjustment of sulfate ratio to increase the lithium yield and reduce production cost. Compared with extracting lithium from brine, extracting lithium from ores, calcination, roasting, purity, and other processes consume more resources and energy; and its environmental impact mainly comes from the pollutants discharged by fossil energy, 9.3‒60.4 times that of lithium extracted from brine. The processing cost of lithium extraction from lepidolite by sulfate roasting method is higher than that from spodumene by sulfuric acid due to the consumption of high-value sulfate. However, the production costs of both are mainly affected by the price of lithium ores, which is less competitive than that of extracting lithium from brine. Thus, the process of extracting lithium from ores should develop appropriate technology, shorten the process flow, save resources and energy, and increase the recovery rate of related elements to reduce environmental impact and improve the added value of by-products and the economy of the process.
Formation and evolution of the South China Sea since the Late Mesozoic: A review
Xue-jie Li, Zhe Wang, Yong-jian Yao, Hong-fang Gao, Song Zhu, Zi-ying Xu
2023, 6(1): 154-167. doi: 10.31035/cg2022021
[Abstract](5015) [FullText HTML] (2725) [PDF 10314KB](47)
The existing genetic models of the South China Sea (SCS) include an extrusion model of the Indochina Peninsula, a back-arc extension model, and a subduction and dragging model of the Proto-South China Sea (PSCS). However, none of these models has been universally accepted because they do not fully match a large number of geological phenomena and facts. By examining the regional tectonics and integrating them with measured data for the SCS, in this study, a back-arc spreading-sinistral shear model is proposed. It is suggested that the SCS is a back-arc basin formed by northward subduction of the PSCS and its formation was triggered by left-lateral strike-slip motion due to the northward drift of the Philippine Sea Plate. The left-lateral strike-slip fault on the western margin caused by the Indo-Eurasian collision changed the direction of the Southwest Sub-basin’s spreading axis from nearly E–W to NE–SW, and subduction retreat caused the spreading ridge to jump southward. This study summarizes the evolution of the SCS and adjacent regions since the Late Mesozoic.
Short Communications (Research Advances)
Report of 2.7 Ga zircon U-Pb age of orthogneiss in the Wenquan metamorphic complex, West Tianshan, China
Chu Wu, Tao Hong, Xing-wang Xu, Cheng-xi Wang, Lian-hui Dong
2023, 6(1): 168-170. doi: 10.31035/cg2021071
[Abstract](5385) [FullText HTML] (2959) [PDF 3834KB](79)
SHRIMP zircon U-Pb age and O isotopic analysis of the dunite from Kudi ophiolite in the West Kunlun, China
Geng-biao Qiao, Wen-ming Li, Tian-hu Li
2023, 6(1): 171-173. doi: 10.31035/cg2021047
[Abstract](5203) [FullText HTML] (2773) [PDF 1793KB](78)
Zircon U-Pb age evidence of the Mesoarchean (2.9–3.2 Ga) crustal remnant in the Southern Dabie Orogen, South China
Da-liang Xu, Lian-hong Peng, Xin Deng, Chao-ran Liu, Le Wan, Xiao-ming Zhao
2023, 6(1): 174-176. doi: 10.31035/cg2022056
[Abstract](2777) [FullText HTML] (1868) [PDF 2140KB](48)
News and Highlights
IUGS released first 100 Geological Heritage Sites and China has seven in the list
Li-qiong Jia, Xi-jie Chen, Ting Jia, Zi-guo Hao
2023, 6(1): 177-182. doi: 10.31035/cg2023004
[Abstract](2104) [FullText HTML] (1576) [PDF 2703KB](7)
An extraordinary multielement apparatus of conodont Nicoraella from the Middle Triassic Luoping Biota, southwest China
Jin-yuan Huang
2023, 6(1): 183-184. doi: 10.31035/cg2023008
[Abstract](1663) [FullText HTML] (1120) [PDF 3188KB](12)
Editorial Committee of China Geology
2023, 6(1): 185-185.
[Abstract](834) [FullText HTML] (808) [PDF 0KB](24)