检索结果-南通市图书馆

Potash-rich volcanic rocks and lamprophyres in western Shandong Province:^(40)Ar-^(39)Ar dating and source tracing

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2002年第2期47卷 91-99页

作者： QIU Jiansheng, XU Xisheng & LO Ching-Huastate key laboratory of mineral Deposit research of nanjing university, nanjing 210093. china Department of Earth Sciences, nanjing university, nanjing 210093. china Department of Geology, Taiwan Unive state key laboratory of mineral Deposit research of nanjing university Nanjing China Department of Earth Sciences Nanjing University Nanjing China Department of Geology Taiwan University Taibei China

Highly precise 40Ar-39Ar dating results demon-strate that the ages of potash-rich volcanic rocks in western Shandong Province are 114.7-124.3 ma, and that of the lamprophyres is 119.6 ma. The potash-rich volcanic rocks have relatively high (87Sr/86Sr)i ratios ( 0.708715-0.711418) and distinctly negative εNd values ( -11.47--17.54), and are enriched in radiogenic lead (206Pb/204Pb=17.341-17.622, 207Pb/204Pb=15.525-15.538, 208Pb/204Pb=37.563-37.684). Similarly, the lamprophyres also have quite low εNd values (-11.57 - -19.64). Based on the fact that the Sr, Nd and Pb isotopic compositions of potash-rich volcanic rocks are very consistent with that of the clinopyroxene separates, and by integrating comprehensive analyses of their tectonic settings, and extensive comparisons of the Sr, Nd isotopic composi-tions with that of the related simultaneous rocks, it is con-cluded that the potash-rich volcanic rocks and lamprophyres in western Shandong Province were most possibly derived from the partial melting

关键词： potash-rich volcanic rocks lamprophyres 40Ar-39Ar dating Sr-Nd-Pb isotope tracing western Shandong Province.

Trace element geochemistry of the Lower Cambrian black rock series from northwestern Hunan, South china

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:materials International 2004年第1期14卷 65-71页

作者： PAN Jiayong 1,2 *, ma dongsheng 1 and CAO Shuanglin 1,2 (1.The state key laboratory for mineral deposits research, nanjing university, nanjing 210093. china 2. East china Institute of Technology, Fuzhou 344000, china) nanjing Univ State Key Lab Mineral Deposit Res Nanjing 210093 Peoples R China E china Inst Technol Fuzhou 344000 Peoples R China

Samples of black rock series collected from the Lower Cambrian Niutitang Formation, northwestern Hunan Province, china, were analyzed for trace elements. The trace element geochemical characteristics of the ore layer (high enrichments of Ni, Mo, V, U, Cu, Pb, Zn, Cd, Tl and Ba; high U/Th ratios and LREE enriched patterns with positive Eu and Y anomalies) support the assumption that the Ni Mo polymetallic layer is of submarine hydrothermal origin. High field strength elements (HFSE) and lithophile elements such as Nb, Ta, Zr, Hf, Li, Be, Rb, Cs, Th and Sc are remarkably higher in the upper unit than those in the lower unit of the Niutitang Formation. These features may reflect that hydrothermal contributions were diminished, and terrigenous constituents were increased in the sediments of the upper unit of the Niutitang Formation.

关键词： black rock series Early Cambrian trace elements northwestern Hunan china

Geothermal and fluid flowing simulation of ore-forming antimony deposits in Xikuangshan

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth Sciences 2006年第8期49卷 862-871页

作者： YANG Ruiyan1,2, ma dongsheng2, BAO Zhengyu3, PAN Jiayong2, CAO Shuanglin2 & XIA Fei2 1. School of mathematics and Physics, china university of Geosciences, Wuhan 430074, china 2. state key laboratory for research of mineral deposits, nanjing university, nanjing 210093. china 3. Faculty of Earth Sciences, china university of Geosciences, Wuhan 430074, china 1. School of mathematics and Physics China University of Geosciences Wuhan 430074 China 2. state key laboratory for research of mineral deposits Nanjing University Nanjing 210093 China 3. Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China

The Xikuangshan Antimony Deposit located in the Mid-Hunan Basin, china, is the larg- est antimony deposit in the world. Based on the hydrogeological and geochemical data collected from four sections, Xikuangshan-Dajienao (AO), Xikuangshan-Dashengshan (BO), Xikuang- shan-Longshan (CO) and Dafengshan (DO) in the Basin, an advanced metallogenic model related to deep-cyclic meteoric water of Xikuangshan Antimony Deposit is put forward in this paper using a model of heat-gravity-driving fluid flow transportation. The simulation results show that the ore-forming fluid of the deposit mainly comes from the Dashengshan and Longshan areas where BO and CO sections are located if the overall basin keeps a constant atmospheric precipitation and infiltration rate during mineralization, and that the average transportation speed of the ore-forming fluids is about 0.2―0.4 m/a.

关键词： ore-forming fluid, numerical simulation, geothermal field, geofluid transport, Xikuangshan, antimony deposits.

mapping soil organic matter in cultivated land based on multi-year composite images on monthly time scales

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2024年第4期23卷 1393-1408页

作者： Jie Song dongsheng Yu Siwei Wang Yanhe Zhao Xin Wang Lixia ma Jiangang Li state key laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Agricultural and Rural Bureau of Luanping County Luanping 068250China Chinese Academy of Sciences university Beijing 100049China

Rapid and accurate acquisition of soil organic matter(SOM)information in cultivated land is important for sustainable agricultural development and carbon balance *** study proposed a novel approach to predict SOM with high accuracy using multiyear synthetic remote sensing variables on a monthly *** obtained 12 monthly synthetic Sentinel-2 images covering the study area from 2016 to 2021 through the Google Earth Engine(GEE)platform,and reflectance bands and vegetation indices were extracted from these composite *** the random forest(RF),support vector machine(SVM)and gradient boosting regression tree(GBRT)models were tested to investigate the difference in SOM prediction accuracy under different combinations of monthly synthetic *** showed that firstly,all monthly synthetic spectral bands of Sentinel-2 showed a significant correlation with SOM(Pmarch,April,October,and ***,in terms of single-monthly composite variables,the prediction accuracy was relatively poor,with the highest R^(2)value of 0.36 being observed in *** monthly synthetic environmental variables were grouped in accordance with the four quarters of the year,the first quarter and the fourth quarter showed good performance,and any combination of three quarters was similar in estimation *** overall best performance was observed when all monthly synthetic variables were incorporated into the ***,among the three models compared,the RF model was consistently more accurate than the SVM and GBRT models,achieving an R^(2)value of *** for band 12 in December,the importance of the remaining bands did not exhibit significant *** research offers a new attempt to map SOM with high accuracy and fine spatial resolution based on monthly synthetic Sentinel-2 images.

关键词： soil organic matter Sentinel-2 monthly synthetic images machine learning model spatial prediction

Incorporation of source contributions to improve the accuracy of soil heavy metal mapping using small sample sizes at a county scale

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2024年第1期34卷 170-180页

作者： Jie SONG Xin WANG dongsheng YU Jiangang LI Yanhe ZHAO Siwei WANG Lixia ma state key laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Chinese Academy of Sciences university Beijing 100049China Agricultural and Rural Bureau of Luanping County Luanping 068250China

Estimating heavy metal(HM) distribution with high precision is the key to effectively preventing Chinese medicinal plants from being polluted by the native soil. A total of 44 surface soil samples were gathered to detect the concentrations of eight HMs(As, Hg, Cu, Cr, Ni, Zn, Pb, and Cd) in the herb growing area of Luanping County, northeastern Hebei Province, china. An absolute principal component score-multiple linear regression(APCS-MLR) model was used to quantify pollution source contributions to soil HMs. Furthermore, the source contribution rates and environmental data of each sampling point were simultaneously incorporated into a stepwise linear regression model to identify the crucial indicators for predicting soil HM spatial distributions. Results showed that 88% of Cu, 72% of Cr, and 72% of Ni came from natural sources;50% of Zn, 49% of Pb, and 59% of Cd were mainly caused by agricultural activities;and 44% of As and 56% of Hg originated from industrial activities. When three-type(natural, agricultural, and industrial) source contribution rates and environmental data were simultaneously incorporated into the stepwise linear regression model, the fitting accuracy was significantly improved and the model could explain 31%–86% of the total variance in soil HM concentrations. This study introduced three-type source contributions of each sampling point based on APCS-MLR analysis as new covariates to improve soil HM estimation precision, thus providing a new approach for predicting the spatial distribution of HMs using small sample sizes at the county scale.

关键词： absolute principal component score-multiple linear regression Chinese herbal medicine influencing factors spatial distribution stepwise multiple regression

Chronological and geochemical studies of granite and enclave in Baimashan pluton, Hunan, South china

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2007年第11期50卷 1606-1627页

作者： CHEN WeiFeng1, CHEN PeiRong1, HUANG HongYe2, DING Xing1,3 & SUN Tao1 1 state key laboratory of mineral Deposit research, Department of Earth Sciences, nanjing university, nanjing 210093. china 2 research Institute No.230, CNNC, Changsha 410011, china 3 Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, china 1. state key laboratory of mineral Deposit research Department of Earth Sciences Nanjing University Nanjing 210093 China 2. research Institute No.230 CNNC Changsha 410011 China 3. Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

Zircon LA-ICP-MS U-Pb dating reveals that the Baimashan Pluton is composed mainly of late Indosinian (204.5±2.8 ma-209.2±3.8 ma) biotite granodiorites/monzonitic granites (LIGs) and early Yanshanian (176.7±1.7 ma) two-micas monzonitic granites (EYGs), and the coeval (203.2±4.5 ma-205.1±3.9 ma) mafic microgranular enclaves (MMEs) are generally found in the former. In addition, the ages of cores within zircons from LIGs and MMEs ranging from 221.4±4.0 ma to 226.5±4.1ma provide evidence of multistage magma intrusion during Indosinian in the study area. Measured 3010±20.6 ma of inherited zircon age suggests that there may be recycling Archaean curstal material in existence in this area. LIGs and EYGs share some similar geochemical features: subalkaline and peraluminous granites, enrichment of Th, U, K, Ta, Zr, Hf and LREE but depletion of Ba, Nb, P, Ti and Eu, low εNd(t) values but high (87Sr/86Sr)i ratios, and old T2DM (ca. 1.9-2.0 Ga). The behaviors of incompatible elements and REE are mainly dominated by fractional crystallization of plagioclase, K-feldspar, ilmenite and apatite, but that of Sr isotope mainly controlled by EC-AFC. They are crust-sourced and derived from partial melting of paleo-Proterozoic metagreywackes and related to biotite dehydration melting. LIGs are formed in post-collisional tectonic setting as crustal local extension and thinning during late Indosinian. But EYGs may be evolved products of congeneric granitic magma with LIGs formed in late Indoinian, which were emplaced again when crust underwent extensive thinning and extension in post-orogenic tectonic setting during Yanshanian in SC after undergoing EC-AFC. MMEs should be cognate enclaves and derived from liquid immiscibility of host magma.

关键词： granite,mafic microgranular enclave,zircon LA-ICP-MS dating,lithogenesis,EC-AFC

Petrogenesis and significance of early Yanshanian syenite-granite complex in eastern Nanling Range

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第7期48卷 912-924页

作者： CHEN Peirong1, ZHOU Xinmin1, ZHANG Wenlan1, LI Huimin2, FAN Chunfang1, SUN Tao1, CHEN Weifeng1 & ZHANG Min1 1. state key laboratory of mineral deposits research, Department of Earth Sciences, nanjing university, nanjing 210093. china 2. Tianjin Institute of Geology and mineral Resources, china Geological Survey, Tianjin 300170, china state key laboratory of mineral deposits research Department of Earth Sciences Nanjing University Nanjing 210093 China Tianjin Institute of Geology and mineral Resources China Geological Survey Tianjin 300170 China

In the eastern Nanling Range there exists the early Yanshanian syenite-granite assemblage. A representative example is the Pitou-Tabei complex composed of the Tabei syenite pluton and the Pitou syenogranite pluton in southern Jiangxi Province. U-Pb zircon dating yields ages of 188.6±2.2 ma for the Tabei pluton and 186.3±1.1 ma for the Pitou pluton. The Tabei syenite is characterized by relatively low SiO2 content (62.40% - 68.75%), high alkalis (K2O+Na2O = 10.56%-11.96%), low percent K2O/Na2O ratios (0.56-0.93), metaluminous fea- ture (A/CNK = 0.80-1.00), enrichment in LILE (Rb, Ba, K) and HFSE (Th, U, Nb, Ta, Zr, and so on), weakly negative to positive Eu anomalies (δ Eu = 0.63-1.82), relatively low (87Sr/86Sr)i (0.70412-0.70543), and relatively high ε Nd(t) (3.14-3.52). The Pitou syenogranite is charac- terized by high silicon content (SiO2 = 71.06%-76.28%), relatively low alkalis (K2O+Na2O = 8.10%-9.80%), high percent K2O/Na2O ratios (1.22-1.94), metaluminous feature (A/CNK = 0.94-1.07), enrichment in Rb, Th (U), K, depletion in Ba, Nb, Ta, Sr, P , Zr, Ti, high ΣREE (av- eraging 451.03 μg/g), strong negative Eu anomalies (δ Eu = 0.27-0.33), relatively high (87Sr/86Sr)i (0.70805-0.70912), and relatively low ε Nd( t ) (?5.35-?6.29). The Tabei syenite and Pitou syenogranite both have the characteristics of A-type granites. The former is considered to be from the asthenosphere mantle, and the latter was the product of the crust-mantle mixture. They both were probably formed in a rifting setting.

关键词： syenite-granite assemblage single zircon U-Pb age rifting environment Nanling Range.

Sm-Nd isotopic ages of Tiqiushan eclogites in Xinyi region and its geological significance

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第S2期44卷 144-146页

作者： WANG Yinxi~(1,2), YANG Jiedong~(1,2), TAO Xiancong~(1,2), GE Ningjie~4, CHEN Peirong~3, FAN Chunfang~3 and LI Jianhua~5 1. Center of Modern Analysis, nanjing university, nanjing 210093. china 2. state key laboratory for research of mineral deposits, nanjing university, nanjing 210093. china 3. Department of Earth Science, nanjing university, nanjing 210093. china 4. Department of Earth and Space Sciences, university of Science and Technology of Chian, Hefei 230026, china 5. No.5 Geological Party of Jiangsu Province, Xuzhou 221005, china Center of Modern Analysis Nanjing University Nanjing 210093 China state key laboratory for research of mineral deposits Nanjing University Nanjing 210093 China Department of Earth and Space Sciences University of Science and Technology of Chian Hefei 230026 China Department of Earth Science Nanjing University Nanjing 210093 China No. 5 Geological Party of Jiangsu Province Xuzhou 221005 China

GEOLOGICAL scientists have paid much attention to the suture zones formed by collision between the Sino-Korean and Yangtze blocks because of the discovery of the ultrahigh pressue metamorphic (UHPM) rocksfrom northern Jiangsu Province (Su), southern Shandong Province (Lu) and the Dabie *** the age of 200-240 ma is probably the best estimation for UHPM metamorphism in the DabieMountains, the primary intrusive and metamorphic ages of the complex from northern Jiangsu Provincehave not been determined before. Using the Sm-Nd isotopic dating method, our study is aimed at datingthe UHPM metanorphic event of northern Jiangsu Province and researching a probable relation between theUHPM rocks from the Dabie Mountains and the UHPM rocks from northern Jiangsu Province.

关键词： northern Jiangsu eclogite rocks Sm-Nd isotopic ages.

The history of crustal uplift and metamorphic evolution of Panzhihua-Xichang micro-palaeoland, SW china:Constraints on Sm-Nd, ^(40)Ar/^(39)Ar and FT ages of granulites

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2004年第8期47卷 689-703页

作者： XU Shijin1, LIU Wenzhong1, WANG Rucheng1, YU Hangbo1, LI Daming2, WAN Jinglin2 & FANG Zhong1 1. Department of Earth Sciences and state key laboratory for mineral deposits research, nanjing university, nanjing 210093. china 2. Institute of Geology, china Seismological Bureau, Beijing 100029, china 1. Department of Earth Sciences and state key laboratory for mineral deposits research Nanjing University 210093 Nanjing China 2. Institute of Geology China Seismological Bureau 100029 Beijing China

Panzhihua-Xichang (Panxi) micro-palaeoland is the oldest terrane on the western margin of the Yangtze Block. Some intermediate-basic granulites are considered to be the crys-talline basement of lower crust in the terrane. Granulite-facies metamorphism of the granulites was developed in the period from 1186 ma to 1128 ma. The origin of granulites was related to the collision orogenic process occurring when the micro-palaeolands merged to form the Rodinia Supercontinent. Amphibolite-facies retrogressive metamorphism of granulites took place in the period from 877 ma to 825 ma. This period was consistent with the breakup time of the Rodinia Supercontinent. 40Ar/39Ar ages and fission track (FT) ages of granulites in the Panxi mi-cro-palaeoland show that the vertical movement history of crustal rocks was a slow uplift process of the rigid terrane in the time from Neoproterozoic to Mesozoic. The subduction of India Plate towards Euroasia Plate resulted in the rapid uplift of the Qinghai-Tibetan Block in Cenozoic. Meanwhile, the Qinghai-Tibetan Block moved towards east. Consequently the Panxi terrane was uplifted rapidly. As a result of the collision orogeny between the Qinghai-Tibetan Block and the Panxi terrane, the granulite-facies crystalline basement in this region was exhumed and exposed to the surface.

关键词： granulite,isotope geochronology,crustal uplift movement,Panzhihua-Xichang region,western margin of Yangtze Block.