First Multi‐Isotopic (Pb‐Nd‐Sr‐Zn‐Cu‐Fe) Characterisation of Dust Reference Materials (ATD and BCR‐723): A Multi‐Column Chromatographic Method Optimised to Trace Mineral and Anthropogenic Dust Sources     

Aubry Vanderstraeten  Steeve Bonneville  Stefania Gili  Jeroen de Jong  Wendy Debouge  Philippe Claeys  Nadine Mattielli 《Geostandards and Geoanalytical Research》2020,44(2):307-329

Atmospheric dust is an integral component of the Earth system with major implications for the climate, biosphere and public health. In this context, identifying and quantifying the provenance and the processes generating the various types of dust found in the atmosphere is paramount. Isotopic signatures of Pb, Nd, Sr, Zn, Cu and Fe are commonly used as sensitive geochemical tracers. However, their combined use is limited by the lack of (a) a dedicated chromatographic protocol to separate the six elements of interest for low‐mass samples and (b) specific reference materials for dust. Indeed, our work shows that USGS rock reference materials BHVO‐2, AGV‐2 and G‐2 are not applicable as substitute reference materials for dust. We characterised the isotopic signatures of these six elements in dust reference materials ATD and BCR‐723, representatives of natural and urban environments, respectively. To achieve this, we developed a specific procedure for dust, applicable in the 4–25 mg mass range, to separate the six elements using a multi‐column ion‐exchange chromatographic method and MC‐ICP‐MS measurements.  相似文献   

滇东南南秧田钨矿床白钨矿原位Sr同位素对成矿的指示     

王忠强  李超  张定才  江小均  周利敏  严清高 《岩矿测试》2020,39(2):285-299

南秧田钨矿床位于滇东南老君山W-Sn矿集区,地处扬子地块和印支地块的结合部位,地质背景复杂并遭受了多期岩浆活动和区域变质事件,其成矿时代和成因一直存在争议。本文对矽卡岩型和长石-石英脉型白钨矿开展了年代学、原位微量元素、Sr同位素研究,分析了两类白钨矿年龄、成因以及物质来源的差异。结果表明,长石-石英脉内与白钨矿共生辉钼矿的Re-Os同位素等时线年龄为151.0±1.3Ma,明显晚于矽卡岩矿体年龄,属于后期成矿事件。矽卡岩型白钨矿的轻稀土富集、重稀土强烈亏损,Eu呈明显负异常(δEu=0.46),∑REE平均含量为65.60μg/g,Mo平均含量为240.16μg/g,Sr平均含量为883.43μg/g;长石-石英脉型白钨矿稀土呈Eu正异常(δEu=2.8)的平坦型,∑REE平均含量为194.40μg/g,Mo平均含量为16.01μg/g,Sr平均含量为129.26μg/g。以上两者微量、稀土元素含量的差别显示它们具有性质明显不同的流体来源,Eu异常指示矽卡岩型白钨矿形成于氧逸度较高的环境,长石-石英脉型白钨矿形成于还原性环境。矽卡岩白钨矿~(87)Sr/~(86)Sr值相对较低,并且比较均一,介于0.71319～0.71491之间,表明成矿流体主要来自岩浆热液;长石-石英脉型白钨矿~(87)Sr/~(86)Sr值较高且变化范围大,介于0.71537～0.72803之间,平均0.72079,呈现出变质流体特征。两种不同类型白钨矿Sr同位素都具有二元混合的特征,显示长石-石英脉型白钨矿对矽卡岩型白钨矿有叠加改造作用,成矿流体与围岩的强烈交代作用是白钨矿形成的关键。  相似文献   

Determination of Radiogenic 87Sr/86Sr and Stable δ88/86SrSRM987 Isotope Values of Thirteen Mineral,Vegetal and Animal Reference Materials by DS‐TIMS     

Jean‐Michel Brazier  Anne‐Dsire Schmitt  Eric Pelt  Damien Lemarchand  Sophie Gangloff  Tho Tacail  Vincent Balter 《Geostandards and Geoanalytical Research》2020,44(2):331-348

This work presents new ⁸⁷Sr/⁸⁶Sr and δ^88/86Sr_SRM987 isotopic values of thirteen mineral, vegetal and animal reference materials. Except for UB‐N, all our results are consistent with previously published data. Our results highlight intermediate precisions among the best presently published and a non‐significant systematic shift with the calculated δ^88/86Sr_SRM987 mean values for the three most analysed reference materials in the literature (i.e., IAPSO, BCR‐2 and JCp‐1). By comparison with the literature and between two distinct digestions, a significant bias of δ^88/86Sr_SRM987 values was highlighted for two reference materials (UB‐N and GS‐N). It has also been shown that digestion protocols (nitric and multi‐acid) have a moderate impact on the δ^88/86Sr_SRM987 isotopic values for the Jls‐1 reference materials suggesting that a nitric acid digestion of carbonate can be used without significant bias from partial digestion of non‐carbonate impurities. Different δ^88/86Sr_SRM987 values were measured after two independent Sr/matrix separations, according to the same protocol, for a fat‐rich organic reference material (BCR‐380R) and have been related to a potential post‐digestion heterogeneity. Finally, the δ^88/86Sr_SRM987 value differences measured between animal‐vegetal and between coral‐seawater reference materials agree with the previously published results, highlighting an Sr isotopic fractionation along the trophic chain and during carbonate precipitation.  相似文献   

A 560–440 ka tephra record from the Mercure Basin,southern Italy: volcanological and tephrostratigraphic implications          下载免费PDF全文

BIAGIO GIACCIO  PAOLO GALLI  EDOARDO PERONACE  ILENIA ARIENZO  SEBASTIEN NOMADE  GIAN PAOLO CAVINATO  MARCO MANCINI  PAOLO MESSINA  GIANLUCA SOTTILI 《第四纪科学杂志》2014,29(3):232-248

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Petrology and geochemistry of the Karaj Dam basement sill: Implications for geodynamic evolution of the Alborz magmatic belt     

《Chemie der Erde / Geochemistry》2015,75(2):237-260

The northeastward subduction of the Neo-Tethyan oceanic lithosphere beneath the Iranian block produced vast volcanic and plutonic rocks that now outcrop in central (Urumieh–Dokhtar magmatic assemblage) and north–northeastern Iran (Alborz Magmatic Belt), with peak magmatism occurring during the Eocene. The Karaj Dam basement sill (KDBS), situated in the Alborz Magmatic Belt, comprises gabbro, monzogabbro, monzodiorite, and monzonite with a shoshonitic affinity. These plutonic rocks are intruded into the Karaj Formation, which comprise pyroclastic rocks dating to the lower–upper Eocene. The geochemical and isotopic signatures of the KDBS rocks indicate that they are cogenetic and evolved through fractional crystallization. They are characterized by an enrichment in LREEs relative to HREEs, with negative Nb–Ta anomalies. Geochemical modeling using Sm/Yb versus La/Yb and La/Sm ratios suggests a low-degree of partial melting of a phlogopite–spinel peridotite source to generate the KDBS rocks. Their low I_Sr = 0.70453–0.70535, ɛNd (37.2 Ma) = 1.54–1.9, and T_DM ages ranging from 0.65 to 0.86 Ga are consistent with the melting of a Cadomian enriched lithospheric mantle source, metasomatized by fluids derived from the subducted slab or sediments during magma generation. These interpretations are consistent with high ratios of ²⁰⁶Pb/²⁰⁴Pb = 18.43–18.67, ²⁰⁷Pb/²⁰⁴Pb = 15.59, and ²⁰⁸Pb/²⁰⁴Pb = 38.42–38.71, indicating the involvement of subducted sediments or continental crust. The sill is considered to have been emplaced in an environment of lithospheric extension due to the slab rollback in the lower Eocene. This extension led to localized upwelling of the asthenosphere, providing the heat required for partial melting of the subduction-contaminated subcontinental lithospheric mantle beneath the Alborz magmatic belt. Then, the shoshonitic melt generates the entire spectrum of KDBS rocks through assimilation and fractional crystallization during the ascent of the magma.  相似文献   

习水县岩溶水系统ρ(Sr2+)、ρ(Sr)/ρ(Ca)、ρ(Sr)/ρ(Mg)分布特征及其应用   总被引：1，自引：0，他引：1  

黄奇波  康志强  覃小群  俞建国  苏春田 《地质科技情报》2011,30(4):98-103

通过对流域内不同类型水取样分析,发现流经不同岩层的地下水具有不同的ρ(Sr2+)、ρ(Sr)/ρ(Ca)、ρ(Sr)/ρ(Mg)值.一般来说,流经砂岩层的基岩裂隙水ρ(Sr2+)低,而ρ(Sr)/ρ(Ca)、ρ(Sr)/ρ(Mg)值较高,当砂岩中的基岩裂隙水受到灰岩岩溶水或煤系地层水补给时,其ρ(Sr2+)、ρ( Sr...  相似文献   

Petrology and Geochemistry of Post-Collisional Early Miocene Volcanism in the Karacada? Area (Central Anatolia, Turkey)     

Kür?ad ASAN  Hüseyin KURT 《《地质学报》英文版》2011,85(5):1100-1117

Early Miocene (ca.?21–18 Ma) volcanism in the Karacada? area comprises three groups of volcanic rocks: (1) calcalkaline suite (andesitic to rhyolitic lavas and their pyroclastics), (2) mildly-alkaline suite (alkali basalt, hawaiite, mugearite, benmoreite and trachydacite), and (3) a single trachyandesitic flow unit. Field observations, 40Ar/39Ar ages and geochemical data show that there was a progressive temporal transition from group 1 to 3 in a post-collisional tectonic setting. The calcalkaline suite rocks with medium-K in composition resemble those of subduction-related lavas, whereas the mildly-alkaline suite rocks having a sodic tendency (Na2O/K2O=1.5–3.2) resemble those of within-plate lavas. Incompatible element and Sr-Nd isotopic characteristics of the suites suggest that the lithospheric mantle beneath the Karacada? area was heterogeneously enriched by two processes before collision: (1) enrichment by subduction-related processes, which is important in the genesis of the calcalkaline volcanism, (2) enrichment by small degree melts from the astenosphere, which dominates the mildly alkaline volcanism. Perturbation of the enriched lithosphere by either delamination following collision and uplift or removal of the subducted slab following subduction and collision (i.e., slab breakoff) is the likely mechanism for the initiation of the post-collision volcanism.  相似文献   

苏北盆地建湖隆起碳酸盐岩储层中的硫酸盐型热矿水成因     

罗璐  庞忠和  杨峰田 《地学前缘》2015,22(2):263-270

碳酸盐岩储层中的硫酸盐型热矿水是宝贵的旅游疗养资源。我国苏北盆地北部分布有丰富的热矿水,其中,盱眙县的一口热水井的单井流量达到3 616t·d-1,矿化度(TDS)达到4g·L-1,温度为53.5℃,为优质硫酸盐型热矿水。采用水化学和同位素方法,结合钻孔地质资料,研究了其形成机理。该地区热矿水的SO2-4离子含量较高,部分热矿水的阴离子中SO2-4离子占主导,成为硫酸盐型水。热水的氢氧稳定同位素(δ2 H、δ18 O)值证明了其来源于大气降水。建湖隆起存在石膏层,主要分布在白垩系浦口组,该组属盐湖相沉积,发育大范围的含膏质泥岩,其中石膏、硬石膏含量较多。根据水样的Sr/Ca摩尔比,该区热水中的硫酸盐来源于石膏的溶解。基于碳酸盐岩热水的pH值和SI值、14 C含量等数据的分析,排除了硫酸盐型热矿水的形成与金属矿的风化或氧化的关系,认为是石膏或硬石膏溶解形成。  相似文献   

花岗岩的成岩时代、地球化学特征和成因青海祁漫塔格地区虎头崖矿床Ⅵ矿带     

姚磊  吕志成  于晓飞  庞振山  蔡煜琦  刘鹏  刘长城  王凤兰 《吉林大学学报(地球科学版)》2015,(3)

利用 LA ICP MS 锆石 U Pb 法,测得与成矿有关的青海祁漫塔格地区虎头崖矿床Ⅵ矿带花岗岩的成岩年龄为(233.6±1.8)Ma(MSWD=1.2,n=17)。地球化学特征显示：花岗岩属高钾钙碱性、弱过铝质花岗岩;样品的稀土元素组成以总体右倾,轻、重稀土分异明显和具明显的负铕异常为特征;微量元素具有富集 Rb、Th、U、La、Nd 等大离子亲石元素,亏损 Ba、Sr、Nb、P、Ti 等元素的特点。Sr Nd 同位素组成特征显示,花岗岩的源区可能是富集岩石圈地幔。初步研究认为,虎头崖矿床Ⅵ矿带花岗岩可能形成于中、晚三叠世碰撞后碰撞的构造背景下。  相似文献   

花岗岩的成岩时代、地球化学特征和成因青海祁漫塔格地区虎头崖矿床Ⅵ矿带     

姚磊  吕志成  于晓飞  庞振山  蔡煜琦  刘鹏  刘长城  王凤兰 《吉林大学学报(地球科学版)》2015,(3):743-758

利用 LA ICP MS 锆石 U Pb 法,测得与成矿有关的青海祁漫塔格地区虎头崖矿床Ⅵ矿带花岗岩的成岩年龄为(233.6±1.8)Ma(MSWD=1.2,n=17)。地球化学特征显示：花岗岩属高钾钙碱性、弱过铝质花岗岩;样品的稀土元素组成以总体右倾,轻、重稀土分异明显和具明显的负铕异常为特征;微量元素具有富集 Rb、Th、U、La、Nd 等大离子亲石元素,亏损 Ba、Sr、Nb、P、Ti 等元素的特点。Sr Nd 同位素组成特征显示,花岗岩的源区可能是富集岩石圈地幔。初步研究认为,虎头崖矿床Ⅵ矿带花岗岩可能形成于中、晚三叠世碰撞后碰撞的构造背景下。  相似文献