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Copyright of Journal of Geomechanics is the property of Journal of Geomechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of High Pressure Physics is the property of Chinese Journal of High Pressure Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This is an article in the field of earth sciences. To reveal the mineral chemistry characteristics and metamorphic temperature of garnet in the Liwu Group due to core of Jianglang dome, the major, trace and rare earth elements of garnet were analyzed at different locations in this paper. The results show that the major-element composition of garnet in schist from the Jianglang dome is mainly Alm. ICP-MS (average content 85.82%) and LA-ICP-MS (average content 83.51%) is basically consistent within the error range of the Alm content obtained.The total content of rare earth elements (REE) is high, and show obvious LREE-depleted and HREE-enriched left-declined REE distribution patterns, with unobvious Eu anomalies and negative Ce anomalies, Enriched in large ionic strength elements (U, Ta, Hf)and depleted high field lithophile elements (K, Sr, Ba). In addition, the formation temperature of garnet in schist from the Jianglang dome is 512～583 ℃, and the formed metamorphic pressure is relatively low. It is a negative correlation between the metamorphic temperature and the distance to the Xinhuoshan granite. In conclusion, the Jianglang dome experienced “Barrovian-type” metamorphism of high greenschist facies.

This is an article in the field of earth sciences. Jiulong area is the most concentrated area of Yanshanian granite found in western Sichuan, including Tiechanghe, Qiaopengzi-Landiao and Xinhuoshangranite. In this paper, LA-ICP-MS zircon U-Pb dating were carried out to determine the formation age of the granite， and its temporal-spatial relationship with the surrounding granites, providing a basis for the comparative study of Liwu copper deposit in the southern margin of Songpan-Ganzi block. The results show thatthe diagenetic age of Huajiaoping granite is (163.1±1.4) Ma, andit underwent magmatic or tectonic thermal events at (146±3) Ma, which is consistent withthe geological events ofTiechanghe, Xinhuoshan and Luomogranite. The magma temperature of Huajiaoping granite is 592～727 ℃ (average temperature 648 ℃), which is significantly lower than that of Qiaopengzi granite (766～804 ℃). Combined with the regional geological background, about 170 ～ 140 Ma, the lithosphere in the southern margin of Songpan Ganzi block is in the extension stage. The granite magma activity dominated in the early stage (163 Ma) by Huajiaoping granite, and in the late stage (146 Ma) by magmatism or tectonic thermal events. This discovery enriched the Yanshannian granitic magmatic thermal events in Jiulong area.

This is an article in the field of earth sciences. The newly discovered Maoping graphite deposit is a super-large crystalline graphite deposit that is located in the middle-northern section of the Kang-Dian fault-uplift belt on the western margin of the Upper Yangtze paleo-continent, and the research on the source of mineralization and its mineralization age is relatively weak. The orebodies occur in the epimetamorphic rocks of Mesoproterozoic Tianbaoshan Formation. In this paper, the geochemical characteristics of major ores, trace amounts and rare earth elements were mainly studied. The results show that the original rock of the ore-bearing rock layer is parametamorphic rock, a set of carbonaceous quartz-bearing siltstone, which is deposited in an oxygen-deficient environment. The characteristics of trace elements indicate that the original rock of the ore body is formed by the deposition of offshore terrigenous clasts. The ores show sedimentary characteristics of coastal tidal flat facies, with an average ΣREE of 158 g/t, average δ Ce value of 0.63 (weak negative anomaly), and an average δ Eu value of 0.69 (negative abnormaly). The graphite ore body has a δ13C value of -28.35‰～-29.08‰, with an average of -28.59‰, indicating that the mineralized carbon is dominated by organic carbon. The LA-MC-ICP-MS Zircon U-Pb of amphibole zircon from Xijie hornblende diorite Zircon is (823.4±3.6) Ma, which is later than the formation era of volcanic rocks of the Tianbaoshan Formation (954 Ma), representing the time of superposition metamorphism of graphite. In summary,the genetic type of the ore deposit is sedimentary- metamorphism and its metamorphism may include the regional dynamic metamorphism of Jinning period that is superimposed by contact metamorphism.

This is an article in the field of earth sciences. Manganese ore is one of the strategic minerals in short supply in China. The area of Northern Guizhou-Eastern Yunnan is the most typical distribution area of manganese ore in Permian, which is also rare in the Late Paleozoic in the world. It is rich in manganese ore resources and has great prospecting potential, so it is called "Zunyi type manganese ore". The results show that the manganese ore is produced in the late Permian Maokou, and its distribution is strictly controlled by the northern Guizhou rift basin. The manganese ore is formed in the center of graben basin by exhalation deposition, but no manganese ore is distributed in the barrier area, and the ore-body spatial distribution direction is basically consistent with the basin distribution direction. Among them, manganese ore in Zunyi - western Guizhou area is spatially distributed in the basin facies area, and can be divided into three manganese ore facies belts, namely, the central phase, the transition phase and the edge, which further indicates the specific metallogenic location of manganese ore and shows that the manganese ore is controlled by the center of the basin. Based on the Zunyi-Xuanwei manganese ore belt, it can be divided into four manganese ore concentration areas in the Zunyi-Qianxi manganese ore mineralization subzone: Shenxi-Bali, Longping-Xinglong, Tuanxi-Shangji and Qianxi, and two manganese ore concentration areas in shuicheng - Xuanwei manganese ore mineralization subzone: Shuicheng - Nayong and Gexue.The research results are of great significance to search for Permian concealed manganese deposits in northern Guizhou and eastern Yunnan and to carry out metallogenic prediction.

This is an article in the field of earth sciences. Xidamingshan polymetallic ore concentration area is critical mineral prospecting district in Guangxi. With the promotion of the large-scale mineral breakthrough work, the Xidamingshan mineral exploration, the Nongtun large-scale Pb-Zn deposit has been newly discovered. However, the understanding of the metallogenic characteristics of the deposit, especially the genesis of the deposit, is still at the superficial stage. Based on detailed field geological investigations and previous work, this paper systematically summarizes the regional metallogenic geological background, mining area and geological characteristics, and analyzes the genesis of the Nongtun lead-zinc deposit to find out the metallogenic mechanism. The study shows the Nongtun Pb-Zn deposit is related-magmatic hydrothermal deposit, the ore-forming fluids originated from magmatic, and later mixed with meteoric water. The fluids extracted Pb and Zn ore-forming elements from the strata during long-distance transport, and combined with S of magmatic fluids to synthesize [HS]-ligand that converged in the fracture zone and transported to the shallow part, thus forming Pb-Zn ore vein. The above research results have established the metallogenic model of the Nongtun Pb-Zn deposit, which provides a good guidance for prospecting prediction and exploration.

This is an article in the field of earth sciences. Magmatic rocks of the Gondwana Belt are one of the most popular problems in basic geological research on the Xizang-Qinghai Plateau. In this paper, we analyze the physical origin and regional tectonic properties of the Gachatai granite using LA-ICP-MS zircon U-Pb dating method, combined with the geochemical characteristics of the rocks and various graphical methods. The rocks are characterized by high alkali (average Na2O+K2O content of 6.26%), potassium (K2O/Na2O=1.03), low TiO2 (average 0.50%) and quasi-aluminous (aluminum saturation index A/CNK=0.933～1.033, average 0.991) high potassium-calcium-alkaline rock system. Rare earth elements show negative anomalies at Eu, which is the Eu-deficient type, and Ce has weak negative anomalies; trace elements show enrichment of large ion-parental elements Rb, Th, Nd, La and K; high field strength elements Nb, Ba, U, Ta, Ce, Sm and Ti are deficient; reflecting the mixed crust-mantle type of magma origin and the presence of subduction oceanic crustal melting. The zircon LA-ICP-MS U-Pb isotopic age is （345.3±1.8） Ma, and its formation age is Early Carboniferous. The analysis of the regional geological data suggests that this magmatic event is a product of the formation of the northern part of the eastern Gondwana continent after the breakup of the Rodinia supercontinent. The project points go to I-type granite, the discriminant diagrams indicate it’s formed from continental island arc, going through time before plate collision to co-collisional orogenic movement, which indicates a long period time of magmatic evolution; the rock geochemical characteristics show the environment of magmatic evolution changed from the start of island arc(primary island arc)-development(early stage island arc)-maturement(full-grown island arc).

This is an article in the field of earth sciences. Taka dome and Jianglang dome are located in the southern margin of Songpan-Ganzi block, and their geological characteristics indicate similar composition and metamorphic-deformation characteristics. Liwu, Heiniudong and Zhongsui deposits have been found in Jianglang Dome, while no similar deposits have been found in the same horizon of Taka Dome. To investigate the medium-deep part structure characteristics and mineralization of the Taka Dome, the geophysical electrical parameters and audio magnetotelluric sounding profiles of different strata of different ages were measured to obtain the electrical characteristics of the middle and deep subsurface. The results show that the overall characteristics of the dome are low and medium resistance on both sides, and high resistance in the core is mainly mixed with low resistance. The overall electrical characteristics are consistent with the spatiotemporal law of the dome structure. There are three main low-resistivity anomaly zones in the deep electrical profile, which are inferred to reflect the low-resistivity lithology, fault or structural fracture zone. The three main high-resistivity anomaly belts are inferred to be reflected by the upper member of the Mesoproterozoic Liwu Group (Pt2l3) with complete medium-high resistivity characteristics in the Taka dome. The above understanding provides geophysical evidence for exploring the medium-deep geological spatial structure of the Taka Dome.

This is an article in the field of earth sciences. According to insufficient research on the distribution characteristics, genetic mechanism, lithium extraction technology, and economic benefits of high-temperature geothermal water lithium resources in Southern Xizang. Through the analysis of plate tectonics, the test of geothermal water components, the comparative analysis of the applicability of lithium extraction technology in salt lakes, and the establishment of an economic evaluation model for lithium extraction from geothermal water, the following achievements have been achieved: (1) The geothermal water lithium in Southern Xizang is mainly distributed on both sides of the Yarlung Zangbo River deep fault zone and its southern region, Lithium-rich granite wall rock leaching and magmatic hydrothermal solution, it provides rich lithium sources for the formation of lithium-rich geothermal water. (2) In accordance with the characteristics of low concentration and low magnesium/lithium ratio in geothermal water lithium, the extraction method and precipitation method are selected to extract and utilize lithium in geothermal water. (3) Take geothermal well in the Gudui geothermal field as an example, with a lithium concentration of 23.5 mg/L in geothermal water, and the extraction process is used to extract lithium, establishing an economic evaluation model, using cash flow method to evaluate the economy, and the economic evaluation results showed that when the price of lithium carbonate is not less than 250000 yuan/t, the extraction of lithium from geothermal water has good economic benefits.

This is an article in the field of earth sciences. Based on the 1∶25000 trench soil geochemical survey carried out in the Yongxi gold polymetallic mining area in Danba County, this paper reveals the element geochemical characteristics and anomaly distribution laws represented by gold, silver, arsenic and antimony in this area, finds a number of valuable geochemical comprehensive anomalies, analyzes the prospecting potential of geochemical anomaly areas, further narrows the prospecting scope, and delimits a prospecting target area. The engineering verification of the target area has achieved good prospecting results, which proves that the trench soil geochemical survey method is effective in the geological exploration work in this area, and provides a scientific basis for further geological work.

This is an article in the field of earth sciences. The copper resources in Ningxia are relatively poor, and 15 copper producing areas have been basically identified, of which 6 deposits have been explored, and the accumulative amount of copper metal has been identified as 29210.71 tons. There are two types of copper deposits: epigenetic medium-low temperature hydrothermal deposit and placer deposit. The mineralization process is magmatism, sedimentation,ore-bearing fluid process (non-magmatic-non-metamorphic process). Copper deposits are mainly distributed in Weining Beishan area, Xiangshan area, South West Huashan area and the southern area of Liupan Mountain. The metallogenic ages are Caledonian, Varissian, Indosinian and Yanshanian, mainly Caledonian and Yanshanian. According to the study on the metallogenic geological law of the existing deposits, the magmatic hydrothermal type and continental sedimentary type are taken as the key prediction types. According to the material composition of the ore-forming series, five ore-forming series related to copper are determined, and the ore-forming genealogy of copper ore is summarized. The research on metallogenic regularity of copper ore is improved. It provides a theoretical basis for the potential evaluation and prediction of copper resources in Ningxia.

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This is an essay in the field of earth sciences. The lithium belt in West Sichuanis the richest area of hard rock lithium resources in China, but the ecological and geological environment in the belt is fragile, so the coordinated development of resources, environment and economy has been a difficult problem for the deep development of regional resources. This paper systematically compares the natural resources, mineral resources, geological environment characteristics and the main environmental geological problems in the lithium belt, constructs an ecological and geological environment carrying capacity evaluation index system based on three subsystems: geological environment, ecological environment and social environment, selects and obtains 19 basic evaluation index data information, and carries out a region-wide carrying capacity evaluation. The results show that: the geological environment of the west Sichuan lithium belt is relatively safe and stable, the existing mining activities in the belt do not have a significant impact on the regional ecological environment, and the impact of human production and life is limited in scope. The proportion of the country area with medium and above carrying capacity reaches 79.16%, the ecological and geological environment carrying capacity in the lithium resource concentration area is high, and the overall ecological and geological environment is in good condition.

This is an essay in the field of earth sciences. With the opening of a new round of mining breakthrough strategic action, the search for key mineral resources such as lithium and rare earth is the core and key to national energy resource security and is crucial to the development of the national economy, national defense and strategic emerging industries. The profile measurement and comprehensive study of the Lower Permian Liangshan Formation (P1l) clay rock system in the Panzhihua area, Sichuan Province are carried out. The key metals such as lithium, gallium and rare earth may come from the weathering products of the underlying layer (ancient weathering crust), which are widely distributed in the area from Panzhihua to Ya 'an. The aluminous clay rock of the Liangshan Formation, which is related to weathering, is a rich layer of lithium, gallium and rare earth metals, which has good prospecting prospects.

Copyright of Arid Land Geography is the property of Chinese Academy of Sciences, Xinjiang Institute of Ecology & Geography and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: It is of great significance to study the breeding environment of the naked carp in Qinghai Lake for the conservation and restoration of natural habitat. The naked carp is the only economic species in Qinghai Lake, colloquially called “Huang Yu”, and plays a core role in the lake ecosystem. As an anadromous species, the naked cap migrates between Qinghai Lake and major rivers to spawn such as the Buha, Shaliu, Quanji, Heima, and Hargai rivers from April to August every year. Due to intensive fishing, arid climate, and the lack of spawning rivers, the amount of the naked carp’s resources has dropped sharply, from 28000 tons in the 1960s to 2263 tons in the 1990s. In view of its important ecological status, it is urgent to restore and protect the resources of naked carp in Qinghai Lake. Since 1982, Qinghai Province has forbidden fishing to restore and protect the fish resources. At the same time, it has established fish conservation bases and artificial breeding and releasing stations around Qinghai Lake. By 2022, the fish resources of the naked carp had increased to 108500 tons, 42 times as many as in the early stages of protection. The breeding environment is the key factor for the continuation of the fish population, and different fish require different parameters of the spawning ground, such as river, light, sediment and water temperature. It is also very important to obtain the reproductive environmental parameters and determine the optimal spawning ground for the protection and expansion of the fish resources. At present, only Zhou et al. have discussed the environmental requirements of natural reproduction of the naked carp by indoor artificial simulation. Therefore, it is of great significance to study the breeding environment of the naked carp for the conservation and restoration of natural habitat. 　 Otolith δ 18O provides a method for fish population identification, migration and environment exploration of spawning ground. Otolith, a calcium carbonate mineral in bony fish, has both auditory and balancing functions and is known as the “recorder” of time and water environment. Microchemical analysis of otolith can reveal the life history and water environment changes of fish. Especially, the core area of otolith is formed at the early stage of incubation, and its microchemical composition can reflect the hydrochemical characteristics of the habitat and solve the problem of fish identification. The otolith δ 18O is closely related to water temperature. Under normal salinity conditions, the δ18O change of 1‰ corresponds to the seawater temperature change of about 5℃. For example, the higher otolith δ 18O values of Pacific bluefin tuna, which migrated across the Pacific from the Western Pacific (WPO) to the Eastern Pacific (EPO), reflected the cold-water temperatures encountered during migration. Similarly, the lower δ18O value in otolith core of Oncorhynchus keta, which migrated between freshwater and marine environments, indicated that Chinese salmon were also anadrotic spawning fish, returned to the ocean after hatching. Yuan et al.[12] analyzed the δ13C and δ18O values in the otolith of small yellow croaker in the Yellow Sea and the Bohai Sea, the population of southern Yellow Sea was subdivided into offshore and coastal populations for the first time, and no station crossing between the two populations was recorded. The overall successful rate of discrimination was recorded to be 82.6% by cluster analysis. Tatsuya et al.[13] conducted otolith δ18O and microstructure analyses to investigate nursery habitat temperatures and early life growth rates. In conclusion, the otolith δ18O provides a method for fish population identification, migration, and environment exploration of spawning ground. In this study, the SHRIMP Ⅱ ion probe was used to determine the otolith δ18O of the naked carp in Qinghai Lake. Combined with the hydrochemical composition of lake water and river water in Qinghai Lake, the optimal migration and spawning sites and environmental conditions of the naked carp were investigated to provide effective information for further revealing its life history. RESULTS: The SHRIMP Ⅱ ion probe was used to determine the in-situ δ 18O composition of the otolith microregion of five naked carp in Qinghai Lake. The in-situ oxygen isotope analysis of otolith was performed by SHRIMP Ⅱ ion probe at the School of Earth Sciences, Australian National University. Sectioned otoliths were prepared for SHRIMP analysis by casting them in epoxy resin, with NBS 18 and 19 reference calcites, to form a 35 mm diameter mount. After being documented by optical photomicroscopy, the samples were coated with high purity Al and transferred to the ANU SHRIMP Ⅱ for analysis using procedures based on those described in detail by Long et al.[21-22] . In brief, the SHRIMP Ⅱ was operated in multi-collector, negative ion mode. A 15kV, ~3nA Cs+ primary ion beam was focused to a 25mm diameter spot on the Al-coated target, producing 200−250pA of secondary 16O − . 16O − and 18O − were measured simultaneously on Faraday cups using Keithley 642 electrometers. Each analysis consisted of a pre-burn of about 3 min to allow the secondary ion isotopic composition to stabilise, followed by 10 or 14 times (10s/time) estimates of the 18O/16O ratio. The accuracy was 0.1‰−0.2‰, and the standard deviation was about 0.3 ‰. The reference material was measured once every 5 samples completed during analysis. The spot starting position of the ion probe was the core of the otolith, along the longest growth axis to the edge. The spot diameter of the ion probe was about 25μm, and the spot depth was about 2−3μm. The spot test was shown in Fig.E.1A. 　　(2) The δ 18O composition along the growth axis of the otolith. The δ 18O ratios along the growth axis of 5 naked carp otoliths were shown in Fig.E.1B. The mean values of otolith δ 18O from No.1 to No.5 were 1.29‰, 1.79‰, 0.99‰, 0.93‰, −7.41‰ respectively, and their interval range were −4.88‰−3.46‰, −0.28‰−3.91‰, −1.43‰−2.94‰, −1.81‰−3.35‰, −9.36‰−5.21‰, respectively. The otolith δ 18O in individual juvenile plaice ranged from 0.2‰ to 1.9‰, when they were reared at two temperatures (11℃ and 17℃), which indicated that the otolith δ 18O ratios were significantly affected by water temperature, but not by feeding level, and there were no significant synergistic effects. The δ 18O ratios of plaice are close to the higher δ 18O ratios of samples 1 to 4 in this study, which is the result of the fact that naked carp lived in the lake with high salinity and low water temperature for part of the time. The Schizothorax kozlovi and the naked carp belong to the subfamily Schizostomus. The average otolith δ 18O ratios of the Schizothorax kozlovi cultured in fresh water is −9.4‰, which is very close to the δ 18O ratios of the naked carp No.5, indicating that sample No.5 has been living in fresh water. The gray bands are the incremental zones of otolith, and the interval zones between the incremental zones are discontinuous zones. The δ 18O ratios of the naked carp in samples 1 to 5 show a trend of lower incremental zones and higher discontinuous zones, because the δ 18O ratios of otolith is inversely correlated with water temperature. The incremental zones of otolith are formed in spring and summer, while the discontinuous zones in autumn and winter, and the water temperature in spring and summer is significantly higher than that in autumn and winter. The otolith δ 18O ratios of the five samples were analyzed by one-way variance analysis. The δ 18O ratios of the No.1, No.3 and No.4 naked carp were not significantly different (P>0.05), while the δ 18O ratios of the No.2 and No.5 naked carp were significantly different from the other three samples (P<0.05). The δ 18O ratios of Qinghai Lake ranged from 1.93‰ to 3.71‰, with an average value of 2.43‰, and that of surrounding rivers ranged from −8.04‰ to −6.20‰. The average δ 18O ratios of Buha River, Shaliu River, Quanji River and Heima River were −6.15‰, −7.21‰, −5.98‰, and −7.31‰, respectively. This is because the δ 18O ratios of different types of water bodies vary greatly, and the δ 18O ratios of lake water are obviously higher than that of surface river water due to strong evaporation. Comparing the δ 18O ratios of lake water and river water with that of 5 samples, it can be seen that the δ 18O signals of lake water and river water are recorded in the otolith of No.1-No.4, indicating that they migrated between lake water and river water, however, the δ 18O signal of river water was only recorded in the otolith of No.5, which indicated that the No.5 naked carp had been living in river water, that is, “sitting water fish”. 　　(3) Composition of δ 18O in otolith cores of the naked carp. The average δ 18O ratios of otoliths from No.1 to No.5 were 1.51 ‰, 0.20 ‰, −0.22 ‰, −2.38 ‰, and −9.14 ‰, respectively, and their interval range were 1.43‰−1.59‰, 0.28‰−0.7‰, 1.02‰−0.64‰, 4.88‰−0.74‰, 9.36‰−8.96‰. The average δ 18O ratios of otolith cores were compared with the δ 18O composition of lakes and rivers, as shown in Fig.E.1C. Since the core area of otolith was formed in the early incubation period of naked carp, the water environment at birth was recorded. From the distribution, the δ 18O ratios of the core area of naked carp No.1-No.3 were closer to the lake water, which indicated that their spawning place was near the estuary. The water body was mixed with lake and river water, and having lower water temperature, which indicated the migration and spawning may have started in late May. The δ 18O ratios of the core area of the No.4 naked carp was closer to the river water, which indicated that the spawning area was far away from the lake and the water temperature was higher, while the No.5 naked carp lived in the river all the time and the water temperature was higher when spawning. In conclusion, the habits of the naked carp are not fixed. Some breed in estuaries, some in upstream rivers, and some migrate between rivers and lakes to spawn, and a small part of the naked carp breed in rivers, which may be related to the local rivers’ cutout in autumn and winter. Some fish that migrate to the upper reaches of rivers to spawn have stayed in rivers for breeding due to the cutout of rivers. Similarly, the otolith cores of Pacific herring born in the Strait of Georgia have lower δ 18O ratios (−8.2‰ to −2.0‰), while the otolith cores of the southern Puget Sound samples have higher δ 18O ratios (−3.9‰ to −0.9‰). DISSCUSION: (1) The relationship between δ 18O ratios of otolith and water temperature. The otolith of the naked carp can record not only the age, but also the water environment and the life history of the fish. The otolith δ 18O ratios of fish is determined by the δ 18O ratios of water body and the water temperature. The δ 18O ratios of the water body are related to the ratio of precipitation to evaporation, runoff and precipitation, while there is an inverse correlation between temperature and otolith δ 18O ratios. The living environment of fish can be inferred from the δ 18O ratios value on the otolith of fish, and the isotopic balance between the surrounding water environment and aragonite minerals is reached or almost reached, therefore, the fractionation of 16O/18O isotopes is closely related to the temperature of the water body, generally showing a negative correlation. For marine fish, the variation of δ 18O ratios at 1‰ corresponds to the variation of sea temperature at about 5℃ under normal salinity conditions. The relationship between temperature variation and otolith δ 18O ratios of freshwater fish at 1‰ has not been established. 　　(2) Experimental research about temperature control on otolith δ 18O ratios. Water temperature, water flow, water depth, riverbed quality and light are the most important environmental parameters in fish breeding. In general, the reproductive activities of fish are not determined by a single environmental factor, and their specific reproductive needs are often multiple environmental factors. When the water temperature of the freshwater tributaries around Qinghai Lake reaches the threshold of 6−16℃, the naked carp will start to migrate, on the one hand, due to the different composition of δ 18O ratios in different spawning sites, and on the other hand, due to the different spawning time, the difference of water temperature is recorded in the otolith δ 18O.The contribution of the δ 18O composition and the change of water temperature to the δ 18O ratios in the otolith of the naked carp cannot be quantified, and needs to be further verified by the artificial control experiment. For example, Nakamura et al.[31] cultured mackerel larvae at six different temperatures (16.3℃, 17.6℃, 18.3℃, 20.0℃, 24.0℃ and 26.5 ℃) and determined the δ 18O ratios, the linear relationship between the water temperature and the otolith δ 18O of mackerel was determined. Willmes et al.[32] reared male oversea fish for 360 days at different salinity (8.75‰, 5.28‰ and 4.06‰) and water temperature (16.4℃, 16.7℃, 18.7℃ and 20.5℃), and then reconstructed the thermal life history of the fish. Wang et al.[33] evaluated whether cooking behavior would lead to further isotopic fractionation of carbonate in otolith and showed that the otolith δ 18O ratios were highly consistent between cooked and uncooked, which indicated the cooking process has no or little effect on the otolith isotope value. 　　(3) Fossil otolith is a good carrier to study the paleoclimate environment. Otoliths are well preserved in sediment, so the fossil otoliths are often used in paleoclimate, palaeoecology and palaeogeography. For example, Wurster et al.[34] analyzed high-resolution δ 18O ratios of Aplodinotus grunniens from the Easterman archeological site to infer climate change in the eastern continental United States during the Holocene. Andrus et al.[35] used the otolith δ 18O ratios of a well-preserved Peruvian catfish fossil to calculate the sea surface temperature of the Peruvian Sea in the Middle Holocene. Surge et al.[36] analyzed the δ 18O ratios of modern and circa 2nd−3rd century AD fossil otoliths of the Mexican sea catfish, and the recovered winter temperatures were very similar to those of modern times. Long et al.[21] analysed the δ 18O ratios of otolith in the sediment of Mungo Lake, Australia, and the variation of the δ 18O ratios indicates an early flood in the lake, a subsequent increase in the δ 18O by 4‰ indicating increasing evaporation of the lake. At the same time, because there is no “Reservoir effect”, the otolith preserved in the sediment is also a good material to measure radioactive carbon. Therefore, fossil otoliths preserved in sediments are not only one of the ideal materials to determine the age of sediments, but also a good carrier to study the paleoclimate environment. 　　(4) Relationship between δ 18O ratios of otolith and fish breeding population. The naked carp in Qinghai Lake is one of the second-class national protected animals in China. Since 1982, Qinghai Province has implemented the closure of the lake to breed fish, covering Qinghai Lake and all the rivers entering the lake. Currently, the sixth closure period in 10 years will end on December 31, 2030. At the same time, the original species preservation bases and artificial breeding and releasing stations have been established around Qinghai Lake. Since 2002, artificial breeding and releasing work has been carried out, and 105 million large-size naked carp fry have been released into the Shaliu and Quanji rivers. Therefore, there should be two populations of natural reproduction and artificial reproduction in Qinghai Lake, and it is difficult to distinguish the two populations only by the otolith δ 18O ratios. 　　(5) In order to identify fish populations more accurately and understand fish life history, many scholars combine the δ 18O and δ 13C ratios of otolith for analysis, because the change of otolith δ 13C ratios can record the maturity of fish and the change in the food chain. For example, Gao et al.[38] analyzed the δ 18O and δ 13C ratios of the otolith core and the second summer season round of Pacific herring in Pikew Bay, Washington, and concluded that there are two types of herring. Ashford et al.[39] tested the δ 18O and δ 13C ratios of cod otolith located on the Patagonia continental shelf and Patagonia in southern Georgia, and found that the δ 18O ratios reflected the sea water temperature in the surrounding environment where the fish lived, so that the different population could be identified. The source of metabolic carbon and the δ 13C ratios of dissolved inorganic carbon (DIC) in seawater affect the δ 13C ratios of otolith. For the first time, Jiang Tao et al.[40] analyzed otolith stable isotope ratios of δ 18O and δ 13C using an isotope ratio mass spectrometry on Coilia nasus juveniles collected from the Changjiang River Estuary. The different environments with different water temperature and food organism composition might be experienced by the two groups of C. nasus fish. He Yongfeng et al.[25] took Sichuan schizostomus of different age groups as the research object to explore the relationship between stable isotopes and environment. The results showed that δ 18O and δ 13C ratios of Schizothorax kozlovi at age 1t were not significantly correlated with otolith mass, but both were significantly different between lapillus and asteriscus. There was no significant difference of lapillus δ 18O and δ 13C between the sexes, but with significant difference among different ages. The correlation of δ 18O with δ 13C was an effective method in identification of different culture stocks of S. kozlovi, which indicates that the isotopic signatures of otolith could be used as a method to identify freshwater fish stocks. [ABSTRACT FROM AUTHOR]

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The 8th symposium on fluid geoscience, mineral resources and environmental disasters reflects the formation and evolution of geological fluids, the enrichment and distribution of mineral resources, and the research progress and development trend of environmental disasters in recent years. The relevant papers of the 8th symposium regarding fluid geoscience, mineral resources and environmental disasters from 6 aspects, including the deep geological processes and mineral resources, the physicochemical techniques of geological fluid research, the fluid geochemical characteristics and seismicity, the occurrence characteristics and development status of geothermal resources, the accumulation characteristics, controlling factors and enrichment rules of geological resources, the fluid geoscience and geographical natural environment, were summarized. The results show that ① the generation and evolution mechanism, enrichment and migration mechanism of oil, gas and mineral resources, and the development of exploration and development technology are still the focus of the current research in the field of fluid geoscience, and the research content also pays more attention to the history and mechanism of resource generation and evolution; ② it is the current main trend to adopt diversified and more accurate new technologies to explore new fields with more complicated geological conditions, deeper burial and more difficult exploration and exploitation; ③ at present, the uncertainty of China's extreme natural disaster risk is affected by many natural, economic and social factors, and it shows an increasing trend; destructive earthquakes are in a period of frequent occurrence, and the sudden, abnormal and complex characteristics of natural disasters are also showing an increasing trend, therefore, it is urgent to improve China's natural disaster prevention and control capacity. [ABSTRACT FROM AUTHOR]

Boron (B) is a light and fluid-mobile element. It has two stable isotopes: 10B and 11B. The two isotopes fractionate significantly in nature due their relatively large mass difference. Therefore, B isotopes are one of the non-traditional stable isotope tracers, which have been used in the research areas of chemistry, environmental, bioscience, earth and planetary sciences. In the last twenty years, the analytical methods of B isotopes have been continuously improved and many important advances have been made. However, there are still some challenges to obtaining high-quality B isotope data. The techniques of B isotope analysis are quite different among laboratories, which arise principally from three stages: sample digestion, purification, mass spectrometry. Because B is volatile and isotopic fractionation may be induced by different coordination in different pH environments, sample digestion, and purification have a great impact on the high - precision measurement of B isotopes. Four digestion methods have been applied for extracting B from samples, including pyro-hydrolysis, acid dissolution, alkali fusion, and ashing. Pyro-hydrolysis requiring large volumes of water is time-consuming. Acid dissolution is one of the most popular techniques due to the small volumes of reagents needed and hence lower levels of contamination. Samples are dissolved with different acids such as hydrochloric, nitric, hydrofluoric, and perchloric. Painstaking attention is required with hydrofluoric acid since BF3 is highly volatile and easily lost in nature. Suitable amounts of mannitol are added during acid dissolution to form a stable boron-mannitol complex to prevent the loss of B and avoid B isotope fractionation. Alternatively, alkali fusion is a dissolution method for solid rock samples. High purity fluxing agent is needed, such as K2CO3, Na2CO3, NaOH, NaOH, and Na2O2. As all the B would be present as borate in the resulting alkaline solution, alkali fusion eliminates the risk of B isotope fractionation due to evaporation. The advantage of this method is that it is rapid and relatively large numbers of samples can be processed. The ashing is mainly used to digest plant samples. Ashing was chosen for plant sample decomposition because ashing removes the organics and avoids the use of reagents carrying a B blank or generating isobaric interferences. Once a sample is dissolved, it is necessary to purify B before analysis. There are two principal methods currently in use, which are ion exchange and microsublimation. The ion exchange techniques can be divided into those involved in using B-specific resin Amberlite IRA 743 and those using cation (AG50W-X8 / AG50W-X12) or anion (Bio-Rad AG MP-1) cation exchange resins. Microsublimation is an effective and simple method to purify B. It is used to purify B from organic-enriched solutions. Microsublimation appears advantageous in terms of matrix removal efficiency and low procedural blank, however the technical challenges involved are also great. There are two main types of B isotope analytical methods: in -situ and solution methods. Solution methods analyse B ratios using thermal ionization mass spectrometry ( TIMS) method or multiple collector inductively coupled plasma-mass spectrometry (MC-ICP -MS). The in-situ method, uses secondary ion mass spectrometry (SIMS) method or laser ablation multiple collector inductively coupled plasma-mass spectrometry (LA-MC-ICPMS) to measure samples with high B concentration. The accurate and precise determination of the B isotope composition is still a difficult task. For solution methods, the difficulty arises principally from the near ubiquitous level of B contamination in most standard clean laboratories, the light mass of the element, the occurrence of only two stable isotopes, and the large mass difference between them. For in - situ approaches, the difficulty arises principally from a lack of reference materials, surface contamination, limited precision in low - concentration samples, and limitations in reproducibility in high -concentration samples. On the whole, MC -ICP -MS is the dominant method for B isotopic analysis, which is still has the challenges of matrix effect, memory effect, and mass bias. The relevant techniques inherent to the three stages of B isotope analysis are summarized and the advantages and disadvantages of the different techniques are discussed. The aim of the work contained in this paper is to further promote the progress and development of domestic and foreign scholars in the research of B isotope geochemistry. [ABSTRACT FROM AUTHOR]

Satellite gravimetry is an efficient technical means to detect the global consistent, high-precision and high-resolution Earth’s gravity field, mainly including high-low satellite-to-satellite tracking (SST-hl), low-low satellite-to-satellite tracking (SST-ll) and satellite gravity gradiometry (SGG). We summarize the main methods to recover the Earth’s gravity field from satellite gravimetry technologies (including SST-hl, SST-ll, SGG and multi-mode combination), and review the latest progress in constructing the static and time-variable gravity field models using challenging mini-satellite payload(CHAMP),gravity recovery and climate experiment(GRACE)/GRACE follow-on(GRACE-FO) and gravity field and steady-state ocean circulation explorer(GOCE) satellite gravity measurements. And the accuracies of the current representative static and time-variable gravity field models are analyzed and evaluated. It is expected to provide reference for the study of the Earth’s gravity field and its geoscience application in the future. [ABSTRACT FROM AUTHOR]

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Objectives: A terrestrial reference system (TRS) is a spatial reference system corotating with the Earth in its diurnal motion in space. A terrestrial reference frame (TRF) is defined as the realization of a TRS, through the realization of its origin, orientation axes and scale, and their time evolution. The TRF is the basis of all surveying and mapping activities and earth science research. Usually, its realization is achieved by a set of physical points with precisely determined coordinates in a specific coordinate system. Methods:The instantaneous positions obtained from different epoch observations are with respect to different reference frames. It is necessary to accumulate the instantaneous positions to form a stable long⁃term reference frame. Taking the instantaneous positions obtained from different epoch observations as input, a fusion model for the long⁃term solutions to a TRF is designed. The function model for the long⁃term solutions is deduced in detail considering the coordinate transformation model and the time⁃varying model of station coordinates. The rank deficiency is solved by applying internal constraints to the Helmert transformation parameters.Results:The daily solutions spanning from 2010⁃08−2014⁃12 from the second reprocessing of International Global Navigation Satellite System Service are used for calculation, and the results are compared with that of the international terrestrial reference frame 2014 (ITRF2014). The results show that for daily solutions the standard deviation is 3.45 mm, 4.04 mm, and 2.84 mm for X, Y and Z directions, respectively, and the weighted root mean square is better than 3 mm for all three directions. In terms of velocity, the accuracy is 1.53 mm/a, 1.46 mm/a, and 1.21 mm/a for X, Y and Z directions, respectively. Conclusions: The derived TRF using the fusion model is consistent with ITRF2014, and the results validate the correctness and reliability of our fusion model, which can provide a theoretical basis for the establishment of the reference frame. [ABSTRACT FROM AUTHOR]

Publishing special issue/column (SI/SC） is important for improving the academic influence of sci-tech journal. The names, number, paper number and page number of SI/SC published by 33 Chinese core geological periodicals from 2012 to 2021 were investigated by CNKI; the publication trend was discussed; and the topic selection and design of SI/SC published by Chinese geological sci-tech journals in different academic levels were suggested. The results show that there are 748 SI/SCs published by 32 Chinese core geological periodicals, only one journal has no SI/SC from 2012 to 2021; SI/SCs increase year by year generally; Earth Science Frontiers is most active in the publication of SI/SC among the 33 Chinese core geological periodicals; the problem-orientated type of SI/SC is predominant, and the number is 603; for the Chinese top-ranking geological sci-tech journals, it is suggested that the journals publish problem-orientated type of SI/SC focusing on national important development strategy, encourage researcher to publish their outstanding scientific achievements in Chinese, in order to serve national socio-economic development better and faster; for the Chinese foremost sci-tech journals in the subdisciplines of geology, it is suggested that the journals publish problem-orientated type of SI/SC focusing on the front field in the subdiscipline, and improve the subdiscipline development; for the other Chinese sci-tech journals, it is suggested that the journals publish spirit-inherited type of SI/SC collecting experts’ and scholars’ strong manuscripts by the emotion, or publish problem-orientated type of SI/SC focusing on local important development strategy, in order to serve local socio-economic development better and faster. [ABSTRACT FROM AUTHOR]

Objectives: Intelligent interpretation based on high-resolution remote sensing is an important way to realize the fine generation and rapid update of geographic information. Based on the background of fine-accurate geographical application using remote sensing, this paper analyzes the limitations of remote sensing information products in production and application. We explain the necessity of remote sensing serving geographical research and the key of coupling the fine shape of the map and the accurate content of the spectrum. Methods: Based on the basic understanding that geography guides the research of intelligent remote sensing, we first put forward the development direction and technical ideas of high-resolution remote sensing geoscience analysis based on fine geographical scenes. Then, we propose an intelligent computing mode via the space-time/satellite-ground collaboration. Furthermore, we take the evaluation of rocky desertification cultivated land in Guanling County, Guizhou Province, China as an application case. Results: Through this case study, three basic models, namely zoning-stratified perception, spatiotemporal synergistically inversion and multi-granular decision-making, are used to show how to carry out fine-accurate application by high-resolution remote sensing collaborative computing in complex mountain areas from a comprehensive perspective of refinement, quantification and topicalization. Conclusions: Combined with the previous work experience and practical cognition, several key scientific problems are discussed, such as spatial expression using irregular grids, multimodal reconstruction of temporal features, multi-source un‐ certainty analysis and iterative optimization guided by uncertainty. We give some potential study directions and research ideas in order to establish a more complete and feasible theoretical system and explore the development paths for the research on intelligent remote sensing under the guidance of geography and the fine-accurate geographical application with remote sensing data. [ABSTRACT FROM AUTHOR]

Objectives: The Earth's radial diameter and mean radius of curvature are the basic parameters commonly used in measurement and Earth science calculation. According to the requirements of Earth science and space science and some requirements, the Earth's radial diameter, mean radius of curvature, mean radius of sphere, equal distance radius of sphere, equal area radius of sphere and equal volume radius of sphere are commonly used. The concept of integral mean values of ellipsoid radius vector and mean radius of curvature is introduced. With the application and development of space technology and computer technology in geodesy and cartography, it is of more important practical value to study the relationship between the Earth's radial diameter and the common Earth radius. Methods: The symbolic expressions of them are deduced by computer algebraic system and are expressed as the power series of eccentricity. We use the method that comparing the radial vector integral mean and the radius integral mean with the four common sphere radius respectively. Results: The results shows that the difference between the radial integral mean and the four common sphere radii is smaller. Since the Earth is a rotating ellipsoid, the radial and the radius of curvature deviate. When the radial vector is the largest, the radius of curvature is the smallest. When the radial is the smallest, the radius of curvature is the largest. Conclusions: The radius of curvature considered by traditional thinking cannot accurately represent the radius of the earth average values, to a certain extent, which means that integral mean value of ellipsoid radius vector is more representative of the average of the Earth's radius. These research results can provide theoretical basis for Earth science, space science and navigation and positioning. [ABSTRACT FROM AUTHOR]

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Copyright of Hydrographic Surveying & Charting / Haiyang Cehui is the property of Hydrographic Surveying & Charting Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Earth Sciences is a multi-disciplinary science, which takes the interaction of Earth's various spheres and their resources and environmental effects as the research object. As a comprehensive and systematic science that not only expands the frontier of human knowledge but also serves the social and economic development of human beings, Earth Sciences not only studies the past and reveals the evolution history of the Earth, but also faces the future and provides solutions for the sustainable development of human beings. Based on the analysis of the international development trends of Earth Sciences and the summary of the development status and sci-tech funding of Earth Sciences in China, this study proposed that the future development direction and research plan of Earth Sciences in China should be arranged from the perspective of system science and national needs; and from the perspective of the Earth system as a whole, while attention should be paid to the interaction of various spheres and elements in the Earth system and their influence on the social and economic development of human beings. It is extremely necessary to guide the development directions of Earth Sciences research with "Four Orientations", carry out major scientific research in an organized way, and improve the mechanisms of sci-tech funding and evaluation, so that the research achievements can better serve the national major strategic needs. [ABSTRACT FROM AUTHOR]

BACKGROUND: Stable chlorine isotope, as an effective tracer, can indicate the water evolution and explore the changes of the geological environment. It has a wide application prospect in earth science. The continuous flow isotope ratio mass spectrometry (CF-IRMS) method has been widely used in the determination of stable isotopes due to the advantages of smaller sample size and higher sensitivity. As a volatile gas, methyl chloride easily escapes during the reaction and the test pipeline, causing sample loss. How to achieve the separation and purification of CH3Cl and improve the conversion rate of CH3Cl of the samples in the reaction and analysis is the key to successful determination of stable chlorine isotopes by CF-IRMS. OBJECTIVES: To understand the influencing factors for the determination of CH3Cl by CF-IRMS. METHODS: The international standard material of chlorine isotope (ISL-354) was chosen as the standard material. The determination method of chlorine stable isotope content in groundwater was studied by using stable isotope ratio mass spectrometer (IRMS) analysis system combined with gas chromatography (GC) separation technology. Three types of samples from analytical pure, standard, and groundwater were chosen. RESULTS: By adopting the combined sampling method of GC manual injection and dual-channel reference gas injection, the loss of methyl chloride during the reaction and testing process was reduced, the concentration of methyl chloride during the online analysis was guaranteed, and better test accuracy was obtained. The results showed that the standard deviation of the 37Cl/35Cl ratio of the samples determined by this method was within the range of 0.20‰. The error of the results from different laboratories was less than 0.035‰, which satisfied the requirement of 0.5‰ reproducibility of geological samples. Parameters such as light, temperature, sulfate removal, continuous helium flow and split ratio were the major factors affecting the test accuracy in the experiment. The influence of these parameters should be strictly controlled in the experiment to ensure the accuracy of this method. CONCLUSIONS: This method has the advantages of simple pretreatment, small sample consumption, large number of test samples and short test period, which can improve the efficiency of the analytical methods of the chlorine stable isotope of groundwater inorganics. [ABSTRACT FROM AUTHOR]

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In order to celebrate the 70th anniversary of Chang'an University, three special issues (Vol. 43, No. 1-3) are published by Journal of Earth S ciences and Environment (JESE) in 2021. The organization, publication, and publicity of the special issues were summarized. JESE Calls for papers from May 2020 to Mar. 2021. The experts and scholars close to Chang'an U niversity, submit 66 high-quality original papers. 39 papers are accepted after double-blind peer r eview, and published in the special issues. The special issues focus on state security of mineral resources, scarce strategic mineral exploration, shale oil exploration, deep geophysical survey, geological survey, prevention of geological hazard, water security and sustainable use, ecological environment management, engineering geology, geomatics and geographic information, land consolidation and planning investigation, and space geophysics, etc. JESE enforces "three reviews and three proofreads" regime in order to improve the academic quality, redesigns the cover and creative title pages, encourages the authors to write warm acknowledgement for celebrating the 70th anniversary of Chang'an University, and publishes the papers online before printing by using CNKI. The papers accepted are immediately reported on the website and Wechat of JESE. JESE will visit the scientific research institutions in the fields of earth sciences and environment, and bring the special issues as a gift for experts and scholars. The above organization, publication, and publicity show that the special issues are high-quality and warm, and positively improve the academic quality of JESE. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: One Rb - Sr certified reference materials (GBW04411) and one Sm - Nd certified reference materials (GBW04419) for geological age, which are potash feldspar and basalt respectively, were produced and certified about 30 years ago. They have only one certified value and their matrices differ from many other geological samples. To better assess the quality of chromatographic separation, measurement procedures and mass spectrometry performance when analyzing Rb - Sr and Sm - Nd, three CRMs which are peridotite, eclogite and granite for Rb - Sr and Sm - Nd analysis were produced, and labelled GBW04139, GBW04140 and GBW04141 respectively. OBJECTIVES: To prepare certified reference materials for analysis of Rb - Sr and Sm - Nd isotopes of different types of rocks. METHODS: Peridotite, eclogite and granite from typical areas in China were used as candidates. Referring to 'Determinations for isotopes of lead, strontium and neodymium in rock samples (GB/T 17672-1999)', 'Determination of Rb Sr isotopic geological age and Sr isotope ratio in rocks and minerals (DZ/T 0184. 4— 1997), Determination of Sm - Nd isotopic geological age and Nd isotope ratio in rocks and minerals (DZ/T 0184.6-1997), Rb, Sr, Sm and Nd were purified by chromatographic separation, and their concentrations were analyzed by ID - TIMS, 87Sr/ 86Sr and 143Nd/ 144Nd ratios were determined by TIMS and MC - ICP-MS, respectively. RESULTS: For homogeneity testing of the three CRMs, fifteen bottles of each were randomly selected (from the 200 bottles prepared) for analysis. F-testing was used to study homogeneity. The result was insignificant (1

BACKGROUND: Cadmium is a volatile element with chalcophile affinity. In the manne environment, Cd is a micronutrient element, while in the ecological environment and agricultural soil environment, Cd is a toxic element. Therefore, Cd isotopes have been used in marine science, earth science, environmental science, and agricultural scientific research, and show great application potential. OBJECTIVES: To summarize the high - precision analytical technology and applications of Cd isotopes in different research fields. METHODS: The recent research progress in digestion methods, separation and purification of Cd, and double - spikes calibration methods for organic matter - rich environmental samples, plant samples and biological samples were summarized. RESULTS: For organic matter - rich samples including environmental, plant and biological samples, microwave digestion, high - pressure ashing and perchloric acid digestion can eliminate the influence of organic matter in Cd isotope analysis. Combined AG MP - 1 ( M) resin with hydrochloric acid leaching system can effectively separate the matrix and interfering elements, which will not result in Cd isotope fractionation. The precision of Cd isotope with m Cd - 113 Cd isotope double - spike correction was around 0. 1 sCd/ amu. The application of Cd isotopes in marine science, geoscience, environmental science, and agricultural science were also summarized in this paper. Cadmium isotopes were used successfully for building marine biological geochemistry cycles, inversion of ancient marine environments and primary productivity change . In sulfide deposits, Cd isotopes were used to trace the evolution of ore fluids and the source of ore metals, and to discriminate different deposit types. In environmental systems, Cd isotopes were applied to distinguish Cd pollution sources, and to investigate Cd sources, migration, circulation and storage mechanisms in agricultural sciences. CONCLUSIONS: The research of the high - precision Cd isotope analytical method and Cd isotope fractionation mechanism and model, will promote to establishment the tracer system of Cd isotope biogeochemistry fractionation and innovative development of non - traditional stable isotope geochemistry. [ABSTRACT FROM AUTHOR]

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The technological progress in the field of artificial intelligence (AI) has brought new opportunities and challenges to the intelligent development and innovative research in geospatial related fields. Geospatial artificial intelligence (GeoAI) refers to the interdisciplinary research direction that combines geography, earth science and artificial intelligence, and seeks to solve major scientific and engineering problems in human-environmental interaction systems through the research and development of spatial intelligence in machines to improve the dynamic perception, intelligent reasoning and knowledge discovery of geographic phenomena and earth science processes. This paper briefly summarizes the historical origins of GeoAI development, introduces spatially explicit and implicit AI models, reviews recent GeoAI research and applications(including spatial representation learning,spatiotemporal prediction and spatial interpolation,monitoring of geographic resources and environment, cartography, and geo⁃text data semantic analysis), and identifies several potential research challenges and directions for the future development of GeoAI. [ABSTRACT FROM AUTHOR]

Hyperspectral remote sensing image is rich in spectral information which has great application potential in forestry, agriculture, geosciences, and other fields. In order to solve the problem of the small sample, multi-dimension, correlation and nonlinearity, and to improve the accuracy of hyperspectral remote sensing image classification, this study proposed a method of hyperspectral image dimension reduction based on t-distribution stochastic neighbor embedding (t-SNE). Convolutional neural network (CNN) was used to extract features and to classify hyperspectral remote sensing images. The t-SNE used the t distribution instead of the Gaussian distribution and defined a symmetric joint probability distribution based on the original SNE, thus it could simplify the gradient calculation. T-distribution was more sensitive to local features because of its long tail character. Using t-distribution instead of Gaussian distribution ensured that the points mapped from high-dimensional space to low-dimensional space were almost unaffected by spatial changes. It was feasible to make intra-class points aggregated closely, and inter-class points dispersed. Meanwhile, it could use the local features of high-dimensional data and maintain the non-linear features of the original data set. To improve the accuracy of hyperspectral remote sensing classification, a novel method based on manifold learning and CNN was proposed. First, the data points in the original high-dimensional space were mapped into the low-dimensional space. The dimensional reduction scale was important for classification results. In order to find the best dimensional reduction scale, an experiment with dimensions ranging from 5 to 30 was conducted. The scale of the Indian Pines dataset was set at 20, the Pavia Center dataset was set at 16 and the Pavia University dataset was set at 18. Perplexity was another important parameter and it had been set at 30 according to the test. Their topological relations were preserved after dimensional reduction. Second, a CNN with a seven layers network structure was designed. It consisted of two convolution layers, two pooling layers, two full connection layers, and one full connection layer. Two convolution layers and two pooling layers existed alternately, and the end of the network related to a full connection layer. A Softmax function was used as a classifier and the AdaGrad algorithm was used for network optimization. With the progress of the optimization process, the learning rate would be reduced for the variables that had decreased a lot. Rectified linear unit (ReLU) has been used as an activation function. The advantages of the ReLU function are more efficient in gradient descent and back propagation because it avoids the problem of gradient explosion and gradient disappearance and it simplifies the calculation process and reduces the overall calculation cost of CNN. The hyperspectral remote sensing data after dimension reduction was used as the input layer to extract the deep features on CNN. Finally, the spatial-spectral features of hyperspectral images were classified. The robustness of the proposed algorithm was verified in three open datasets; (i) Indian Pines, (ii) Pavia Center and (iii) Pavia University. The overall accuracy of classification in three data sets had reached 99.05%, 99.43%, and 98.90%. The proposed algorithm showed a better effect on dimension reduction compared with the original CNN. Since t-SNE was more sensitive to local features and considered inter-class differences, remarkable results had been achieved for small ground object samples. Compared with the original CNN, the problem of "salt and pepper noise" in the hyperspectral image was solved effectively and the overall classification accuracy was significantly improved. The method of manifold learning and convolutional neural networks could also provide a new approach for the hyperspectral remote sensing image classification. It was usually difficult to obtain the labeled sample data of the hyperspectral image, while the performance of the deep learning model depended on many mark samples. In future work, we would consider how to construct the classification model under the condition of limited labeled samples to obtain better classification results. [ABSTRACT FROM AUTHOR]