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oxygen isotope Characteristics of the Footwall Alteration Zones in the Hongtoushan Volcanogenic Massive Sulfide Deposit,Liaoning Province,China and Restoration of Their Formation Temperatures

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Acta Geologica Sinica(English Edition) 2011年第3期85卷 683-693页

作者： ZHENG Yuanchuan GU Lianxing TANG Xiaoqian LIU Sihai WU Changzhi LI Chunhai Institute of Geology Chinese Academy of Geological Sciences 26 Baiwanzhuang Road Beijing 10003 7 China State Key Laboratory for Endogenic Metal Deposits Research （Nanjing University）＂ Department of Earth Sciences Nanjing University Nanjing 210093 China

The Hongtoushan Volcanogenic Massive Sulphide Deposit（VMSD）occurs in the Hunbei granite-greenstone terrane,Liaoning Province,NE China.Rocks in the mining area have been metamorphosed around 3.0-2.8 Ga to upper amphibolite facies at temperatures between 600℃and 650℃.Cordierite-anthophyllite gneiss（CAG）in the Hongtoushan mining area,which occurs hundreds of meters below the ore horizon,corresponds to the metamorphosed semi-conformable alteration zone of the VMSD hydrothermal system,whereas the one immediately below the main ore layer represents the metamorphosed pipe-like alteration zone.Whole-rock oxygen isotope signatures were well preserved in both types of CAGs,although the mineral components have been entirely changed during regional metamorphism.Therefore,whole-rock oxygen isotopes can be used to estimate the formation temperature of both types of alteration zone.Calculations show that the semi-conformable and pipelike alteration zones for the Hongtoushan submarine hydrothermal system were formed at 290-360℃and 285-320°C,respectively,whereas estimates for the former were slightly higher than that of the latter,indicating that the semi-conformable alteration zone represents the deep part of the Hongtoushan seafloor hydrothermal system,while the pipe-like alteration zone represents the discharge conduits for metal-rich fluids,which is closer to the seafloor.

关键词： oxygen isotope formation temperature VMSD footwall alteration zones Hongtoushan Liaoning Province

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Origin of the springtime South China Sea Warm Current in the southwestern Taiwan Strait: Evidence from seawater oxygen isotope

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Science China Earth Sciences 2020年第10期63卷 1564-1576页

作者： Dongyu CHEN Ergang LIAN Yeqiang SHU Shouye YANG Yalong LI Chao LI Pengfei LIU Ni SU State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China

oxygen isotope(δ^18O)of seawater is an excellent proxy for tracing the origins of water masses and their mixing processes.Combining with hydrographic observation,hybrid coordinate ocean model(HYCOM)analysis data,and seawater oxygen isotope,we investigated the source of the South China Sea Warm Current(SCSWC)in the southwestern Taiwan Strait and its underlying mechanism.Results show that the Kuroshio subsurface water(KSSW)can intrude the continental slope in the southwestern Taiwan Strait,and thereby climb up the continental slope coupled with upwelling.Theδ^18O-salinity relationship further indicates that in spring,the SCSWC in the southwestern Taiwan Strait originates from the upslope deflection of the slope current formed by the KSSW intrusion into the South China Sea,rather than from the west segment of the SCSWC formed to the east of Hainan Island.In addition,the southward flowing Zhe-Min Coastal Current(ZMCC)can reach as far as the Taiwan Bank(TB)and deflects offshore over the western TB at approximately 23.5°N,to some extent affecting the SCSWC.Moreover,this study reveals that seawaterδ^18O is exquisitely sensitive to the determination of the origin and transport of water masses as compared with traditional potential temperature-salinity plot(θ-S)and HYCOM analysis data.In addition,their coupling can more reliably interpret the mixing processes of shelf water masses.

关键词： oxygen isotope South China Sea Warm Current Zhe-Min Coastal Current Kuroshio Southwestern Taiwan Strait

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In-situ LA-ICP-MS trace element and oxygen isotope signatures of magnetite from the Yamansu deposit,NW China,and their significance

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Acta Geochimica 2020年第5期39卷 599-615页

作者： Zhiyuan Sun Yuwang Wang Lingli Long Technic Research Center for Deep Resources Exploration in Non-ferrous Metal Mines Beijing Institute of Geology for Mineral Resources5 YardBeiyuanChaoyang DistrictBeijing 100012China

The Yamansu iron deposit is hosted in submarine volcanic rocks in the Aqishan–Yamansu belt of Eastern Tianshan,NW China.A geological cross-section for the Carboniferous strata in the ore district shows that ore bodies in the Yamansu deposit are hosted in andesitic crystal tuff of the third cycle of the Carboniferous Yamansu Formation.This indicates an association between mineralization and volcanism.The orebodies are strata bound and lensoid and generally share the occurrence state of the host rocks.Magnetite mineralization mainly occurs asbreccia ores,ores in the mineralized volcanic rocks,massive ores,and sulfide-rich ores according to their structures and sequences of formation.Trace element compositions of magnetite from various types of ores were determined by LA-ICP-MS.The dataset indicates thatdifferent types of magnetite havedistinct trace element contents correlated to their formation environments.Magnetite crystals from breccia ores have high Ti,Ni,V,Cr,and Co and low Si,Al,Ca,and Mg contents,indicating crystallization from a volcanic magmatic eruption,which is consistent with field evidence of coexisting altered volcanic breccia.Magnetite crystals from ores in the mineralized volcanic rocks have moderate Ti,Ni,V,Cr,and Co contents.In contrast,magnetite from massive ores and sulfide-rich ores have low concentrations of Ti,Cr,Ni,and V,high concentrations of Si,Al,Ca,and Mg,and evidence of hydrothermal magnetite.In-situ magnetite compositions imply a magmatic-hydrothermal process.Although d18 O values for magnetite grains from Yamansu vary(?1.3 to?7.0%),they all plot in the range field of volcanic iron deposits,and they also record a magmatic-hydrothermal process.The compositions of Yamansu magnetites are interpreted as controlled mainly by temperature,fluid,host rock buffering,oxygen fugacity,and sulfur fugacity.The metallogenic conditions of the Yamansu deposit changed from high temperature and low oxygen fugacity to low temperature and high oxygen fugacity.However,more fluid-rock reactions and higher s

关键词： Magnetite Trace element composition LAICP-MS oxygen isotope Yamansu iron deposit Eastern Tianshan

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Quartz-Ferberite oxygen isotope Geothermometer and Its Geological Applications

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Acta Geologica Sinica(English Edition) 1992年第3期66卷 271-281页

作者： Ding Tiping Liu Yushan Wan Defang Liu Zhijian Li Jincheng Zhang Guilan Institute of Mineral Deposits, Chinese Academy of Geological Sciences, Beijing Institute of Mineral Deposits Chinese Academy of Geological Sciences Beijing

Experiments for oxygen isotope exchange between ferberite and water were carried out and the followingequation on oxygen isotope fractionation between ferberite and water against temperature was obtained:Combining this equation with the equation of Clayton et al. (1972) on oxygen isotope fractionation be-tween quartz and water, an equation on oxygen isotope fractionation between quartz and ferberite was ob-tained:The Bigeleison-Mayer function method was used to calculate the oxygen isotope fractionation betweenquartz and ferberite. The theoretical curve obtained agrees with the experimental calibration results quite wellin the temperature range of study.The above calibrated equation has been used in 5 world famous tungsten deposits to determine their tem-peratures of formation. The results show that the temperature range for an idividual deposit determined by thisgeothermometer agrees with those obtained from fluid inclusion determination and other isotopegeothermometers.

关键词： geothermometer oxygen isotope quartz--ferberite

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Typical oxygen isotope Profile of Altered Oceanic Crust Recorded in Continental Intraplate Basalts

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Journal of Earth Science 2017年第4期28卷 578-587页

作者： Huan Chen Qun-Ke Xia Etienne Deloule Jannick Ingrin School of Earth Sciences Zhejiang UniversityHangzhou 310027China School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China UMET UMR CNRS 8207Universite de Lillel59655 Villeneuve d'AscqFrance CRPG UMR 7358CNRS Universite de Lorraine54501 Vandoeuvre-les NancyFrance

Recycled oceanic crust （ROC） has long been suggested to be a candidate introducing en- riched geochemical signatures into the mantle source of intraplate basalts. The different parts of oceanic crust are characterized by variable oxygen isotope compositions （δ^18O=3.7‰ to 13.6‰）. To trace the sig- natures of ROC in the mantle source of intraplate basalts, we measured the δ^18O values of clinopyroxene （cpx） phenocrysts in the Cenozoic basalts from the Shuangliao volcanic field, NE China using secondary ion mass spectrometer （SIMS）. The δ^18O values of the Shuangliao cpx phenocrysts in four basalts ranging from 4.10‰ to 6.73‰ （with average values 5.93‰±0.36‰, 5.95‰±0.30‰0, 5.58‰±=0.66‰e, and 4.55‰±= 0.38‰, respectively） apparently exceed those of normal mantle-derived cpx （5.6‰±0.2‰） and fall in the typical oxygen isotope range of altered oceanic crust. The δ^18O values display the negative correlations with the Eu, Sr anomalies of whole rocks and erupted ages, demonstrating that （1） the ROC is the main enriched component in the mantle source of the Shuangliao basalts and （2） the contributions of ROC var- ied with time. The basalt with the lowest δ^18O value is characterized by a significant K positive anomaly, highest H2O/Ce and Ba/Th ratios, suggesting that the mantle source of basalts with low δ^18O can also in- clude a water-rich sediment component that may be the trigger for partial melting. Considering the continuous subduction of the Pacific slab, the temporal heterogeneity of the source components is likely to be caused by the Pacific slab subduction.

关键词： continental basalt oxygen isotope recycled oceanic crust Pacific slab eastern China.

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High resolution oxygen isotope and grayscale records of a medieval fossil giant clam(Tridacna gigas) in the South China Sea: physiological and paleoclimatic implications

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Acta Oceanologica Sinica 2014年第8期33卷 18-25页

作者： YAN Hong WANG Yuhong SUN Liguang State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of Sciences Institute of Polar Environment School of Earth and Space SciencesUniversity of Science and Technology of China Advanced Management Research Center Ningbo University

Mollusks are well known for their detailed recording of paleoenvironmental and paleoclimatic changes in their carbonate shells. In this study, we constructed 18-year blue color intensity and oxygen isotope profiles of a14C dated （AD 990±40） fossil giant clam,Tridacna gigas, from Shidao Island, South China Sea. Theδ18O profile of theT. gigas specimen displayed regular annual cycles and was probably controlled by seasonal variations of the climatic parameters. The blue color intensity profile showed good agreement with theδ18O series, and both had 18 clear annual cycles in accordance with the 18 visually identified annual growth bands. The annual shell growth rate determined from the blue color intensity and oxygen isotope profiles indicated that the annual shell increment of theTridacna specimen was stable after the onset of sexual ma-turity. Spectral analysis of theδ18O and blue color intensity time series suggested that the El Ni？o-Southern Oscillation （ENSO） period observed in the instrumental temperature and precipitation records of the South China Sea during the past 50 years also existed in medieval times. Our results showed that fossil giant clams could provide a good archive of historical intra-seasonal to decadal climate variations.

关键词： Tridacna gigas oxygen isotope blue color intensity Medieval Warm Period sea surface temperature El Ni?o–Southern Oscillation

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A preliminary study on oxygen isotope of ice cores of Collins Ice Cap,King George Island,Antarctica

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Chinese Journal of Polar Science 1997年第1期8卷 67-73页

作者：闫明

Glacier forming material shows no difference of oxygen isotope for different heights above sea level on Big Dome of Collins Ice Cap. δ 18 O variations of surface firn with depth(time) are extremely similar. Owing to the material and energy exchange between different annual layers, homogeneity of oxygen isotope arises and leads to no avail of δ 18 O ice core dating on Big Dome Summit of Collins Ice Cap. Affected by seasonal variations of temperature, oxygen isotope composition of winter layer is distinctly different from that of summer layer whose δ 18 O value is higher and variation coefficient is smaller. By means of direct comparison oxygen isotope/temperature gradient of Collins Ice Cap is defined as 0.74‰/℃ in use of annual mean temperature and δ 18 O value on Big Dome Summit and Small Dome Top of Collins Ice Cap.

关键词： Collins Ice Cap oxygen isotope climate temperature.

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Sources and transformations of nitrite in the Amundsen Sea in summer 2019 and 2020 as revealed by nitrogen and oxygen isotopes

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Acta Oceanologica Sinica 2023年第4期42卷 16-24页

作者： Yangjun Chen Jinxu Chen Yi Wang You Jiang Minfang Zheng Yusheng Qiu Min Chen College of Ocean and Earth Sciences Xiamen UniversityXiamen 361102China School of Marine Science and Fisheries Jiangsu Ocean UniversityLianyungang 222005China

In this study,the nitrogen and oxygen isotope compositions of nitrite in the upper 150 m water column of the Amundsen Sea in the summer of 2019 and 2020 were measured to reveal the distribution and transformation of nitrite in the euphotic zone of the Southern Ocean.We found that primary nitrite maxima(PNMs)are widely present in the Amundsen Sea,where the depth of occurrence deepens from east to west and nitrite concentrations increases.Evidence from dual isotopes suggests that the formation of PNMs in all regions of the Amundsen Sea is dominated by ammonia oxidation.More importantly,the nitrogen and oxygen isotope compositions of nitrite in the Amundsen Sea mixed layer are abnormal,and their depth profiles are mirror symmetrical.Isotopic anomalies exhibit spatial variations,with central surface water having the lowest nitrogen isotope composition(−89.9‰±0.2‰)and western surface water having the highest oxygen isotope composition(63.3‰±0.3‰).Isotopic exchange reaction between nitrate and nitrite is responsible for these isotope anomalies,as both nitrogen and oxygen isotopes have large isotopic fractionation and opposite enrichment effects.This proves that isotopic exchange reaction operates extensively in different regions of the Amundsen Sea.Our study highlights the unique role of dual isotopes of nitrite in deepening the understanding of nitrogen cycle.Further studies on ammonia oxidation and isotopic exchange between nitrate and nitrite are warranted in the future to understand their roles in the nitrogen cycle in the Southern Ocean.

关键词： nitrogen isotope oxygen isotope nitrite Amundsen Sea

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oxygen isotope compositions of eclogites in Rongcheng,Eastern China

Oxygen isotope compositions of eclogites in Rongcheng,Easter...

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中国科学院地质与地球物理研究所2003学术年会

作者： CHU Xuelei~(1,2),GUO Jinghui~(1,2),FAN Hongrui~(1,2) & JIN Chengwei~1 1.Institute of Geology and Geophysics.Chinese Academy of Sciences, Beijing 100029,China: 2.Key Laboratory for Mineral Resources Research.Chinese Academy of Sciences,Beijing 100101,China Correspondence should be addressed to Chu Xuelei

Collected from the Rongcheng region,Shandong Province,the three types’of eclogites suffering the UHP (i.***.ultra-high pressure)metamorphism have obviously different oxygen isotope compositions.The eclogites occurring in regional orthogneisses and ultramafic rocks have the oxygen isotope compositions of normal eclogites in the world, but the eclogites existing in marbles are extremely enriched in O.By applying oxygen isotope geothermometry,for the all types of eclogites,the temperature estimates of quartzgarnet pair,in principle,indicate the formation temperatures of eclogites,so that the peak-metamorphic temperatures are estimated to be averagcly little higher than 800℃,which are consistent with the estimates by using other geothermometers according to cation partitioning between coexisting phases.TheδO values of eclogitic inclusions hosted in marbles from Yangguantun,Rongcheng region,are far higher than the values of eclogites(including eclogitic inclusions in marbles)from the Dabieshan and other places of the Sulu.The oxygen isotope compositions of various minerals indicate that the formation temperatures of eclogites from the Rongcheng region,in general,are higher than that from the Dabieshan and the southwestern part of the Sulu,but the dispersive temperatures estimated by different mineral pairs probably reflect that the UHP eclogites from the Rongcheng region generally suffered overprinted metamorphisms during the exhumation.

关键词： Sulu UHP terrain eclogite oxygen isotope formation temperature overprinted metamorphism

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Study on Analytical Methods for Hydrogen and oxygen isotope in Water Sample

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Acta Geologica Sinica(English Edition) 2014年第S1期88卷 175-175页

作者： ZHANG Lin LIU Fuliang Institute of Hydrogeology and Environmental Geology

1 Introduction The stable isotopes of hydrogen and oxygen(δ2H andδ18O)are excellent tracers for studies on the natural water cycle.The isotopic signature of different water bodies

关键词： hydrogen isotope oxygen isotope equilibration technique metal chromium

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