检索结果-南通市图书馆

Acta Geochimica 2022年第2期41卷 197-207页

作者： Yong Zhang Haibo Zhao Lei Liu Jiayong Pan Likuan Zhu Guoqi Liu Xiaotian Zhang State Key Laboratory of Nuclear Resources and Environment(East China university of Technology) Nanchang 330013China Zhengzhou Institute of Multipurpose utilization of Mineral Resources CAGSZhengzhou 450006China Institute of Geological Survey of East China university of Technology Nanchang 330013China Xining Center of Natural Resources Comprehensive Survey CGSXining 810000China

Eastern Qinling,China is one of the important rare metal metallogenic provinces with extensively distributed granite pegmatite dikes.The No.5 granite pegmatite intruded into the granitic gneiss of the Qinling Group,and the major minerals are quartz(39.8%),K-feldspar(18.8%),albite(36.3%),muscovite(3.4%),and garnet(1.1%).Monazite u–pb isotopic dating indicates that the No.5 pegmatite from the Eastern Qinling was emplaced at ca.420.2±2.2 Ma,which confirms that highpurity quartz mineralization probably formed during the Early Devonian.In-situ laser ablation inductively coupled plasma mass spectrometry analysis of quartz show that quartz samples from Eastern Qinling have total trace element concentrations(Al,Ti,Sc,Li,B,Cr,Mn,and Fe)ranging from 23.2 to 52.8 ppm,slightly higher than the quartz(impurity element content from 13.4 to 25.9 ppm)of the Spruce Pine high-purity quartz deposit in western North Carolina.The No.5 pegmatite of Eastern Qinling could be defined as one high-purity quartz deposit of China.

关键词： Monazite LA-ICP-MS u-pb High-purity quartz Granite pegmatite Eastern Qinling

Hunting the Datable Garnet using the LA-ICP-MS u-pb Method:Predicting Garnet u Concentration,based on Major and Minor Elements

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2022年第6期96卷 2148-2157页

作者： DENG Yi ZHONG Richen LI Dengfeng LI Yanxia CuI Hao School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China School of Marine Sciences Sun Yat-sen UniversityZhuhaiGuangdong 519082China Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering ZhuhaiGuangdong 519082China

Garnet occurs in a wide range of rock types,from mantle peridotites to granites,from eclogites to skarns.In recent years,garnet LA-ICP-MS(Laser Ablation Inductively Coupled Plasma Mass Spectrometry)u-pb dating has provided a powerful solution for retrieving the ages of rock formations,but successful dating is often prohibited by the low concentration of u.However,the concentration of u,a trace element of garnet,is unknown prior to the LA-ICP-MS analysis.In this study,we propose that the u concentration in garnet can be predicted by the contents of major and minor elements,which can be quantitatively obtained by EPMA(electron probe microanalysis).using a supervised machine learning method(neural network),a model is trained to discriminate u-rich(>2 ppm)and u-poor(ults.Results of cross validation shows that the model has an average accuracy of~92%and is a powerful tool in detecting datable u-rich garnet.To facilitate the use of the discriminator,it is programmed as a stand-alone Microsoft Excel spreadsheet(HighuGarnet)and users directly paste the molar proportions of garnet end members into it and obtain the discrimination result.

关键词： garnet u-pb LA-ICP-MS machine learning

Genetic links of porphyry Mo-epithermal pb–Zn–Ag mineralization system:a case study of the Shipingchuan polymetallic deposit,South China

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2022年第2期41卷 307-323页

作者： Yongbin Wang Peiling Feng Lingli Zhou Qingdong Zeng Yunnan Key Laboratory of Earth System Science Yunnan University650500 KunmingChina Key Laboratory of critical minerals metallogeny in universities of Yunnan province Yunnan University650500 KunmingChina iCRAG and School of Earth Sciences University College DublinBelfi eld Dublin 4Ireland Key Laboratory of Mineral Resources Institute of Geology and GeophysicsChinese Academy of Sciences100029 BeijingChina Innovation Academy for Earth Science Chinese Academy of Sciences100029 BeijingChina College of Earth and Planetary Sciences University of Chinese Academy of Sciences100049 BeijingChina

Compared with the porphyry Cu-epithermal Au mineralization system,detailed studies on the porphyry Mo-epithermal pb–Zn–Ag–Au mineralization are rare due to limited exposures.The Shipingchuan polymetallic deposit,located in the South China Mo Province(SCMP)represents a typical example containing both porphyry Mo and epithermal pb–Zn–Ag mineralization.The Mo mineralization mainly occurs as molybdenite-quartz veins in veinlets or as disseminated molybdenite within the potassic,silicic,and sericitic syenogranite.The pb–Zn–Ag mineralization is characterized by veinlet-type sphalerite–galena–pyrite–quartz–calcite vein within the volcanic rocks accompanied with silicifi cation and propylitization.Five molybdenite samples yield a Re–Os isochron age of 104.7±0.7 Ma that is consistent with the zircon age(107.5±2.1 Ma)of the ore-bearing syenogranite within errors.Together with previous reported Ar–Ar ages(106.6–121.8 Ma)of pb–Zn–Ag related volcanic rocks,the Mo and pb–Zn–Ag mineralization belong to a magmatic-hydrothermal event in the Early Cretaceous.Meanwhile,the total Re contents of molybednite range from 1.28 to 45.55 ppm,indicating the ore-forming materials were from a mixture between the mantle and crustal material.Moreover,previous sulfur isotopic values(3.7–4.3‰)of the pyrites from the porphyry Mo mineralization were consistent with the reported range of 4.0–6.1‰of the sphalerites from the pb–Zn–Ag mineralization,implying that the sulfur of two-types of mineralization was derived from magma.The above-mentioned spatial,temporal,and isotopic lines of evidence suggest that the Mo and pb–Zn–Ag mineralization of the Shipingchuan deposit was formed from the same metallogenic system.In consideration of regional tectonic evolution history,we propose that the porphyry Mo-epithermal pb–Zn–Ag mineralization formed in an extensional tectonic setting caused by the continued rollback and the eventual slab break-off of the subducting PaleoPacifi c plate.

关键词： u-pb Re-Os Shipingchuan South China Mo Province Porphyry Polymetallic deposit

Laser ablation in situ u-pb dating and its application to diagenesis-porosity evolution of carbonate reservoirs

在线全文

学校读者我要写书评

暂无评论

Petroleum Exploration and Development 2019年第6期46卷 1127-1140页

作者： SHEN Anjiang Hu Anping CHENG Ting LIANG Feng PAN Wenqing FENG Yuexing ZHAO Jianxin Key Laboratory of Carbonate reservoirs CNPCXihu DistrictHangzhou 310023China PetroChina Hangzhou Research Institute of Geology(HIPG) Xihu DistrictHangzhou 310023China Radiogenic Isotope Facility School of Earth and Environmental SciencesThe University of QueenslandBrisbaneQLD 4072Australia Beijing SHRIMP Center Institute of GeologyChinese Academy of Geological Sciences(CAGS)Haidian DistrictBeijing 100037China Research Institute of Exploration and Development PetroChina Tarim OilfieldKorla 841000China

Through the development and calibration of a reference material which is 209.8 Ma old using a newly-developed Laser Ablation(LA)Multi-Collector Inductively Coupled Plasma Mass Spectrometry(MC-ICP-MS)technique,we successfully overcome the difficulty in sampling and dating ultra-low u-pb ancient marine carbonates,which was previously untenable by isotope dilution(ID)methods.We developed the LA-MC-ICP-MS in situ u-pb dating technique for ancient marine carbonates for the study of diagenesis-porosity evolution history in Sinian Dengying Formation,Sichuan Basin.By systematically dating of dolomitic cements from vugs,matrix pores and fractures,we found that the burial and diagenetic process of dolomite reservoirs in Sinian Dengying Formation was characterized by progressive filling-up of primary pores and epigenic dissolution vugs.The filling of vugs happened in three stages,early Caledonian,late Hercynian-Indosinian and Yanshanian-Himalayan,while the filling of matrix pores mainly took place in early Caledonian.The unfilled residual vugs,pores and fractures constitute the main reservoir sapce.Based on the above knowledge,we established the diagenesis-porosity evolution history of the dolomite reservoir in Sinian Dengying Formation,Sichuan Basin.These findings are highly consistent with the tectonic-burial and basin thermal histories of the study area.Our study confirmed the reliability of this in situ u-pb dating technique,which provides an effective way for the investigation of diagenesis-porosity evolution history and evaluation of porosity in ancient marine carbonate reservoirs before hydrocarbon migration.

关键词： laser ablation in-situ u-pb dating Sichuan Basin Sinian Dengying Formation diagenesis-porosity evolution carbonates

Zircon SHRIMP u–pb age of Late Jurassic OIB-type volcanic rocks from the Tethyan Himalaya: constraints on the initial activity time of the Kerguelen mantle plume

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2018年第3期37卷 441-455页

作者： Yuruo Shi Chenyang Hou J. Lawford Anderson Tianshui Yang Yiming Ma Weiwei Bian Jingjie Jin Beijing SHRIMP Center Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China China university of Geosciences Beijing 100083 China Department of Earth and Environment Boston UniversityBoston MA 02215 USA

This work presents zircon u–pb age and wholerock geochemical data for the volcanic rocks from the Lakang Formation in the southeastern Tethyan Himalaya and represents the initial activity of the Kerguelen mantle plume. SHRIMP u–pb dating of zircons from the volcanic rocks yielded a ^(206) pb/^(238) u age of 147 ± 2 Ma that reflects the time of Late Jurassic magmatism. Whole rock analyses of major and trace elements show that the volcanic rocks are characterized by high content of Ti O_2(2.62 wt%–4.25 wt%) and P_2O_5(0.38 wt%–0.68 wt%), highly fractionated in LREE/HREE [(La/Yb)N= 5.35–8.31] with no obvious anomaly of Eu, and HFSE enrichment with no obvious anomaly of Nb and Ta, which are similar to those of ocean island basalts and tholeiitic basaltic andesites indicating a mantle plume origin. The Kerguelen mantle plume produced a massive amount of magmatic rocks from Early Cretaceous to the present, which widely dispersed from their original localities of emplacement due to the changing motions of the Antarctic, Australian, and Indian plates. However, our new geochronological and geochemical results indicate that the Kerguelen mantle plume started from the Late Jurassic. Furthermore, we suggest that the Kerguelen mantle plume may played a significant role in the breakup of eastern Gondwanaland according to the available geochronological, geochemical and paleomagnetic data.

关键词： Volcanic rocks Late Jurassic ZirconSHRIMP u-pb age Kerguelen mantle plume TethyanHimalaya Lakang Formation

Possible early Neoproterozoic magmatism associated with slab window in the Pingshui segment of the Jiangshan-Shaoxing suture zone: Evidence from zircon LA-ICP-MS u-pb geochronology and geochemistry

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2009年第7期52卷 925-939页

作者： CHEN ZhiHong GuO KunYi DONG YongGuan CHEN Rong LI LongMing LIANG YiHong LI ChunHai Yu XiMing ZHAO Ling XING GuangFu Nanjing Institute of Geology and Mineral Resources Nanjing 210016China Department of Earth Sciences The University of Hong KongHong KongChina College of Earth Sciences Jilin UniversityChangchun 130026China Zhejiang Pingtong Gorporation Shaoxing 310520China

We report here geochemical data, u-pb zircon ages, and Hf isotopes for the high-Mg diorites (HMDs), Nb-enriched basaltic porphyrys (NEBPs) and plagiogranites (PLAGs) in the Pingshui segment of the Jiangshan-Shaoxing suture zone. The HMDs are characterized by high Mg# (>60), high Na and LREE contents, depletion of HREE and HFSE, and pronounced positive εNd(t) values of 7.0 to 7.7, similar to some adakitic high-Mg andesites. The NEBPs are relatively Na-rich (Na2O/K2O>6) and display high abundances of P2O5 (~1.00%), TiO2 (~3.08%) and HFSE (e.g., Nb=9.53-10.27 ppm). Their Nd isotopic compositions (εNd(t)=6.8-8.0) are comparable to those of the HMDs. The PLAGs are metaluminous (A/CNK=0.84-0.89) and sodic (Na2O/K2O>10). Their depletion in HFSE (e.g., Nb, Ta) is consistent with 'SSZ-type' plagiogranite. Zircon LA-ICP-MS u-pb dating yields an age of 932±7 Ma for the HMD, 916±6 Ma for the NEBP, and 902±5 Ma for the PLAG, respectively, indicating that they were products of early Neoproterozoic magmatism. The PLAGs exhibit relatively high zircon Hf isotopes and positive εHf(t) values of 11.0 to 16.2, consistent with their Nd isotopic data (εNd(t)=7.5-8.4). Such features are similar to those of oceanic plagiogranites in ophiolites and distinct from those of crust-derived granites. The PLAGs were most likely derived from partial melting of subducted oceanic crust in an active continental margin. Considering these results in the context of the regional geology, we suggest that a slab window in the subducting oceanic crust between the Yangtze Block and Cathaysia Block was possibly the principal cause for the unique arc magmatism in the area. The upwelling asthenosphere below the slab window may have provided significant thermodynamic conditions.

关键词： zircon LA-ICP-MS u-pb dating geochemistry slab window early Neoproterozoic Pingshui of Shaoxing Jiangshan-Shanxing suture zone

Constraints on sedimentary ages of the Chuanlinggou Formation in the Ming Tombs, Beijing, North China Craton: LA-ICP-MS and SHRIMP u–pb dating of detrital zircons

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2018年第2期37卷 257-280页

作者： Jing Ding Yuruo Shi Alfred Kroner J. Lawford Anderson Beijing SHRIMP Center Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China China university of Geosciences Beijing 100083 China Institut fur Geowissenschaften Universitat Mainz55099 Mainz Germany Department of Earth and Environment Boston University Boston MA 02215 USA

Detrital zircons in five sedimentary samples,MC1 to MC5, from the bottom of the Chuanlinggou Formation in the Ming Tombs District, Beijing, were dated with the LA-ICP-MS and SHRIMP u–pb methods. Age spectra of the five samples show a major peak at 2500 Ma and a secondary peak at 2000 Ma, suggesting their provenances were mainly from the crystalline basement of the North China Craton and the Trans-North China Orogen.The youngest zircon has an age of 1673 ± 44 Ma, indicating that the Chuanlinggou Formation was deposited after this age. From sample MC4 to MC5, lithology changed from a clastic rock(fine-grained sandstone) to a carbonate rock(fine-grained dolomite), suggesting that the depositional basin became progressively deeper. The age spectrum of sample MC5 shows a major peak at 2500 Ma and a secondary peak at 2000 Ma. Sample MC4, which is stratigraphically lower than sample MC5, only had one peak at 2500 Ma. We conclude that there was a transgressive event when sediments represented by MC5 was deposited, and seawater carried ca. 2000 Ma clastic materials to the basin where the Chuanlinggou Formation was deposited, leading to the addition of ca. 2000 Ma detritus.Our research indicates that the source area for the sediments became more extensive with time. We conclude thatthe Chuanlinggou Formation in the Ming Tombs District was deposited in a low-energy mud flat sedimentary environment in the inter-supra tidal zone because it is mainly composed of silty mudstone and fine-grained sandstone with relatively simple sedimentary structures.

关键词： LA-ICP-MS 沉积结构 u-pb 年龄中国锆石岩屑北京

Zircon u-pb Geochronology and Geochemistry of the Middle Permian Siliceous Clastics and Basalt from Central Qiangtang, Northern Tibet: Implications for the Evolution of Permian

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2019年第2期30卷 286-295页

作者： Xueren Li Jian Wang Chinese Academy of Geological Sciences China university of Geosciences Key Laboratory for Sedimentary Basin and Oil and Gas Resources Ministry of Land and Resources Chengdu Center of China Geological Survey

In this study, we report zircon u-pb age and geochemical data on the Middle Permian siliceous clastics and basalt samples of Lugu Formation collected in the Yaqu region from central Qiangtang. Combined with the published data, we establish the spatial and temporal evolution of the rift in central Qiangtang from the Early to Late Permian. Zircon u-pb dating by LA-ICP-MS yields a concordant age with a weighted mean 206 pb/238 u age of 266.6±2.8 Ma(n=6, MSWD=0.55) for the basalt. The results of detrital zircons from the siliceous clastics exhibit a prominent population of 257–270 Ma with a maximum depositional age of 265.4±2.6 Ma(n=19, MSWD=2.7) and three minor populations with peak ages of 450, 700–800, 1 800 Ma, as well as one older age of 2 039 Ma, generally coinciding with the geological events that occurred at different epochs in Qiangtang. The basalts display enrichments in highfield-strength elements(HFSE) such as Th, Ta and Hf, but show relative depletion in large-ion-lithophile elements(LILE) such as Ba, K and Sr, as well as slight depletion in Nb and exhibiting no Eu anomalies. All the samples are distributed in the within-plate setting on the Zr vs. Zr/Y and Th/Hf vs. Ta/Hf discrimination diagrams. The integration of these new data together with the regional geological background indicates that the Lugu Formation was formed in a continental rift-related setting of the central Qiangtang terrane during the Middle Permian. We propose a temporal and spatial framework that the continental rift opened as a result of the break-up of Gondwana during the Early Permian, ran to its peak in the Middle Permian and closed in the Late Permian(290–257 Ma), which could be a key constraint on the Permian evolution of Qiangtang.

关键词： zircon u-pb siliceous clastics basalt Qiangtang Middle Permian

u–pb zircon age of the base of the Ediacaran System at the southern margin of the Qinling Orogen

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2018年第3期37卷 414-421页

作者： Lecai Xing Taiyi Luo Zhilong Huang Zhikuan Qian Mingzhong Zhou Hongtao He School of Earth Science and Engineering Hebei University of Engineering Handan 056038 China State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081 China Guizhou Minzu university Guiyang 550025 China School of Geographical and Environmental Sciences Guizhou Normal University Guiyang 550001 China

Global abrupt climate change from Marinoan snowball Earth to greenhouse Earth, recorded as cap carbonate overlain on diamictite, had shed the first light on Cambrian bio-radiation. The most documented cap carbonate sections are typical with comprehensive d13 C negative values and ubiquitous sedimentary structures, such as tepee-like, sheet-crack etc., which are associated with successive glacial eustatic variation caused by isostatic rebound in shallow-water facies. Here we report a deepwater basinal cap carbonate section with strong negative δ^(13) C values in the southern margin of the Qinling Orogen,Heyu, Chengkou County, Chongqing in China, which consists of massive dolostone with abundant carbonaceous laminae. However, it lacks the sedimentary structure as mentioned above and is overlain by thin-bedded silicious shales and cherts. A K-bentonite bed was discovered within the base of cap carbonates, about 0.7 m above the top of the Marinoan diamictite. Magmatic zircons that were separated from the K-bentonite bed yield a SIMS concordia u–pb age of 634.1 ± 1.9 Ma(1 r, MSWDCE= 0.31,ProbabilityCE= 1.000, n = 20). The age is in good agreement with previously reported TIMS u–pb ages for the termination of Marinoan glaciation and provides ageochronological constraint for the Ediacaran successions in the Qinling Orogen.

关键词： Neoproterozoic Cap dolostone K-bentonite u-pb age Qinling Orogen

新疆北部喇嘛苏铜矿床成矿时代与构造背景:来自石榴子石原位LA-ICP-MS u-pb测年的证据

在线全文

学校读者我要写书评

暂无评论

现代地质 2023年第3期37卷 645-661页

作者：王晓彤刘军杨艳何军成中国地质科学院矿产资源研究所自然资源部成矿作用与资源评价重点实验室北京100037 中国地质大学(北京) 北京100083 中国地质调查局发展研究中心北京100037

石榴子石是矽卡岩型矿床中最常见的蚀变矿物,石榴子石u-pb定年技术的发展应用为准确限定矽卡岩成矿作用时代提供了新手段。我国西天山地区发育大量矽卡岩型铜矿床,由于缺乏精确的成矿年代学数据,制约了矿床成因和成矿动力学背景认识的... 详细信息

石榴子石是矽卡岩型矿床中最常见的蚀变矿物,石榴子石u-pb定年技术的发展应用为准确限定矽卡岩成矿作用时代提供了新手段。我国西天山地区发育大量矽卡岩型铜矿床,由于缺乏精确的成矿年代学数据,制约了矿床成因和成矿动力学背景认识的深入。为了精确厘定西天山地区矽卡岩型铜矿化时代,本文选取代表性的喇嘛苏大型铜矿床矽卡岩带中石榴子石为研究对象,利用电子探针和LA-ICP-MS原位u-pb定年技术开展了矿物成分和年代学分析。根据喇嘛苏矿床石榴子石的岩相学特征,将其分为红棕色石榴子石、浅棕色石榴子石和黄绿色石榴子石三类。电子探针分析显示,三类石榴子石的端元组分均主要为钙铁榴石(56.96%~85.09%),其次为钙铝榴石(14.33%~43.85%),属于钙铁榴石-钙铝榴石系列。u-pb定年获得3件石榴子石的加权平均年龄介于(389.1±2.0)~(387.0±2.3)Ma之间,表明成矿时间为中泥盆世。结合区域构造演化史,喇嘛苏矽卡岩型铜矿床形成于北天山洋壳的俯冲环境。

关键词： LA-ICP-MS u-pb 石榴子石矽卡岩喇嘛苏新疆