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   

安徽黄梅尖地区基性岩脉K-Ar年代学、地球化学特征及地质意义          下载免费PDF全文

杨彪  王正其  肖金根  曹达旺 《华东地质》2020,(1):27-35

在野外地质调查和室内综合研究的基础上,通过对黄梅尖地区辉绿玢岩K-Ar年代学、地球化学和Sr-Nd同位素特征进行研究,探讨辉绿玢岩的形成时代、岩石成因及构造背景。K-Ar年代学研究表明,辉绿玢岩形成于~107 Ma,是早白垩世岩浆活动的产物,形成时代晚于该地区火山岩和侵入岩,与该地区铀成矿年龄基本一致;辉绿玢岩的侵入可能是该地区岩浆作用的最后一幕,铀成矿可能与辉绿玢岩具有成因联系。地球化学特征表明,辉绿玢岩富集大离子亲石元素K、Rb、U、Pb和轻稀土元素,亏损高场强元素Nb、Ta、P、Ti,具有较高的Isr值和负εNd(t)值,具有富集地幔源区特征;辉绿玢岩是在地壳伸展和岩石圈减薄的构造背景下,由俯冲交代作用形成的富集地幔部分熔融形成的,表明~107 Ma时该地区仍处于伸展构造环境下。  相似文献   

Petrogenesis of granitoids from the Lachlan Fold Belt,southeastern Australia: The role of disequilibrium melting     

《Gondwana Research》2020

S- and I-type granites from the Lachlan Fold Belt, southeastern Australia, have been investigated to assess the role of disequilibrium melting in their petrogenesis. Differences between the median initial εHf compositions of magmatic zircon populations and the host bulk-rock (ΔεHf^blk-zrc) range from −0.6 to +2.5 ε units, providing evidence for intra-sample (and hence inter-phase) Hf-isotopic heterogeneity. Linear variations on Harker diagrams and O and Hf isotope compositions of magmatic zircon preserved in many I- and S-type granites are inconsistent with assimilation or simple mixing hypotheses. In contrast, isotopic disequilibrium between the melt and a restite assemblage can explain the bulk-rock versus zircon differences observed in these samples.Assuming that magmatic zircon records the melt composition, differences between the bulk-rock εHf and εHf of magmatic zircon (ΔεHf^blk-zrc values) measured for I-type granites (0.4–2.5) can largely be explained by disequilibrium amphibole dehydration melting of meta-igneous protoliths that were either isotopically heterogenous at the time they were formed, or perfectly homogeneous before being aged in the crust for 0.4–1.0 billion years prior to partial melting. The Currowong Suite exhibits petrographic features and preserves geochemical and isotopic compositions that do not lend themselves to simple restite model or magma mixing explanations; however, these observations could be explained by the restite unmixing of magma batches generated from a single source rock if, as modelling has suggested, separate batches contain different melt compositions.By investigating the application of disequilibrium melting to granite genesis, this study demonstrates that isotopic heterogeneity at various sampling scales should actually be expected for the production of granites from a single source, rather than necessitating the involvement of multiple sources and mixing processes. As a result great care should be taken in the interpretation of isotope data from granitic bulk-rocks or their zircons.  相似文献   

New Reference Materials and Assessment of Matrix Effects for SIMS Measurements of Oxygen Isotopes in Garnet     

Alice Vho  Daniela Rubatto  Benita Putlitz  Anne‐Sophie Bouvier 《Geostandards and Geoanalytical Research》2020,44(3):459-471

Accurate ion microprobe analysis of oxygen isotope ratios in garnet requires appropriate reference materials to correct for instrumental mass fractionation that partly depends on the garnet chemistry (matrix effect). The matrix effect correlated with grossular, spessartine and andradite components was characterised for the Cameca IMS 1280HR at the SwissSIMS laboratory based on sixteen reference garnet samples. The correlations fit a second‐degree polynomial with maximum bias of ca. 4‰, 2‰ and 8‰, respectively. While the grossular composition range 0–25% is adequately covered by available reference materials, there is a paucity of them for intermediate compositions. We characterise three new garnet reference materials GRS2, GRS‐JH2 and CAP02 with a grossular content of 88.3 ± 1.2% (2s), 83.3 ± 0.8% and 32.5 ± 3.0%, respectively. Their micro scale homogeneity in oxygen isotope composition was evaluated by multiple SIMS sessions. The reference δ¹⁸O value was determined by CO₂ laser fluorination (δ¹⁸O_LF). GRS2 has δ¹⁸O_LF = 8.01 ± 0.10‰ (2s) and repeatability within each SIMS session of 0.30–0.60‰ (2s), GRS‐JH2 has δ¹⁸O_LF = 18.70 ± 0.08‰ and repeatability of 0.24–0.42‰ and CAP02 has δ¹⁸O_LF = 4.64 ± 0.16‰ and repeatability of 0.40–0.46‰.  相似文献   

Distinguishing the Regional Atmospheric Controls on Precipitation Isotopic Variability in the Central-Southeast Portion of Brazil     

Vinícius dos SANTOS  Peter MARSHALL FLEMING  Luís HENRIQUE MANCINI  Stela DALVA SANTOS COTA  Graziele Beatriz de LIMA  Rafaela RODRIGUES GOMES  Roberto Eduardo KIRCHHEIM  Ricardo SANCHéZ-MURILLO  Didier GASTMANS 《大气科学进展》2022,39(10):1693-1708

Precipitation isotope ratios (O and H) record the history of water phase transitions and fractionation processes during moisture transport and rainfall formation. Here, we evaluated the isotopic composition of precipitation over the central-southeastern region of Brazil at different timescales. Monthly isotopic compositions were associated with classical effects (rainfall amount, seasonality, and continentality), demonstrating the importance of vapor recirculation processes and different regional atmospheric systems (South American Convergence Zone-SACZ and Cold Fronts-CF). While moisture recycling and regional atmospheric processes may also be observed on a daily timescale, classical effects such as the amount effect were not strongly correlated (δ¹⁸O-precipitation rate r ≤ –0.37). Daily variability revealed specific climatic features, such as δ¹⁸O depleted values (~ –6‰ to –8‰) during the wet season were associated with strong convective activity and large moisture availability. Daily isotopic analysis revealed the role of different moisture sources and transport effects. Isotope ratios combined with d-excess explain how atmospheric recirculation processes interact with convective activity during rainfall formation processes. Our findings provide a new understanding of rainfall sampling timescales and highlight the importance of water isotopes to decipher key hydrometeorological processes in a complex spatial and temporal context in central-southeastern Brazil.  相似文献   

The influence of political ideology on greenhouse gas emissions     

《Global Environmental Change》2022

This research tests the casual link from political ideology to national greenhouse gas emissions by utilizing multinational panel data covering 98 countries during the period 1990–2016. Overall, the baseline results and robustness tests show a political divide on national greenhouse gas emissions, whereby compared to right-wing governments, left-wing governments are more likely to exhibit less carbon dioxide emissions. We further explore this topic from the perspectives of energy efficiency and education. Three-stage OLS regressions suggest that leftist parties increase energy efficiency and spend more on secondary education, which lead to less greenhouse gas emissions. We also introduce the interaction between political ideology and economic performance as well as globalization to test the moderating effects of economic performance and globalization. The study further looks into the interaction effects of political ideology and democracies on greenhouse gas emissions by dividing the whole sample into two sub-samples. The results indicate that the ideology effect on greenhouse gas emissions varies among countries with different economic performances or different degrees of political globalization, as well as between democracies and non-democracies.  相似文献   

Environmental regulation and innovation: Evidence from China     

《Global Environmental Change》2022

The relevance of analyzing effects of environmental regulation on innovation cannot be overemphasized. In this paper, we first develop a theoretical model to predict how command-and-control environmental regulation affects innovation, and then we derive its channels. Using the difference-in-difference-in-differences strategy and a comprehensive dataset at city-industry-year level of manufacturing sectors in China, we found that the more stringent environmental regulations that are faced by cities, measured by the reduction targets of chemical oxygen demand (COD) and sulfur dioxide (SO₂) during the eleventh Five-Year Plan, are negatively associated with innovation. Thus, the evidence contradicts the Porter Hypothesis. On average, a one standard deviation increase in the reduction targets of COD (SO₂) is associated with a 0.023 (0.016) standard deviation decrease in the innovation index. We controlled carefully for various potential confounders, and the results were supported by robustness and falsification checks. There exists an evident heterogeneity effect across regions and industries with different pollution intensities. The channel analysis shows that stricter environmental regulation also accounts for a sharp decline in labor demand, firm entry, and inbound foreign direct investment. Our findings are also robust to alternative measures for innovation and environmental regulation.  相似文献   

Evolution of Siderian juvenile crust to Rhyacian high Ba-Sr magmatism in the Mineiro Belt,southern São Francisco Craton     

Hugo Moreira  Luís Seixas  Craig Storey  Mike Fowler  Stephanie Lasalle  Ross Stevenson  Cristiano Lana 《地学前缘(英文版)》2018,9(4):977-995

Plutonic rocks from the Mineiro Belt, Brazil record a delayed onset of the transition from TTG to sanukitoid-type magmatism(high Ba-Sr), starting during the Siderian magmatic lull when little juvenile magma was added to the continental crust. Rocks mostly belong to the calc-alkaline series, meta-to peraluminous and originally "Ⅰ-type",meaning that oxidized magmas were formed by partial melting of subducted material. The temporal distribution and apparent secular changes of the magmas are consistent with the onset of subduction-driven plate tectonics due to an increase of the subduction angle and opening of the mantle wedge. New isotopic analyses(Sm-Nd whole rock and Lu-Hf in zircon)corroborate the restricted juvenile nature of the Mineiro Belt and confirm the genetic link between the Lagoa Dourada Suite,a rare ca. 2350 Ma high-Al tonalite-trondhjemite magmatic event, and the sanukitoid-type ca. 2130 Ma Alto Maranhao Suite. U-Pb dating of zircon and titanite constrain the crystallisation history of plutonic bodies; coupled with major and trace element analyses of the host rocks, they distinguish evolutionary trends in the Mineiro Belt. Several plutons in the region have ages close to 2130 Ma but are distinguished by the lower concentration of compatible elements in the juvenile high Ba-Sr suite.  相似文献   

Formation and evolution of the Archean continental crust of China: A review     

《China Geology》2018,1(1):109-136

The mainland of China is composed of the North China Craton, the South China Craton, the Tarim Craton and other young orogenic belts. Amongst the three cratons, the North China Craton has been studied most and noted for its widely-distributed Archean basement rocks. In this paper, we assess and compare the geology, rock types, formation age and geochemical composition features of the Archean basements of the three cratons. They have some common characteristics, including the fact that the crustal rocks prior to the Paleoarchean and the supracrustal rocks of the Neoarchean were preserved, and Tonalite-Trondhjemtite-Granodiorite (TTG) magmatism and tectono-magmatism occurred at about 2.7 Ga and about 2.5 Ga respectively. The Tarim Craton and the North China Craton show more similarities in their early Precambrian crustal evolution. Significant findings on the Archean basement of the North China Craton are concluded to be: (1) the tectonic regime in the early stage (>3.1 Ga) is distinct from modern plate tectonics; (2) the continental crust accretion occurred mostly from the late Mesoarchean to the early Neoarchean period; (3) a huge linear tectonic belt already existed in the late Neoarchean period, suggesting the beginning of plate tectonics; and (4) the preliminary cratonization had already been completed by about 2.5 Ga. Hadean detrital zircons were found at a total of nine locations within China. Most of them show clear oscillatory zoning, sharing similar textures with magmatic zircons from intermediate-felsic magmatic rocks. This indicates that a fair quantity of continental material had already developed on Earth at that time.  相似文献   

承德市臭氧污染气象条件预报方法研究   总被引：1，自引：0，他引：1  

陆倩  王国辉  付娇  周士茹 《气象与环境学报》2019,35(6):67-76

利用2014-2016年承德市环境监测站和气象站的数据,分析了气象条件对承德市O₃-8h浓度的影响,探讨了臭氧污染气象条件的预报方法。结果表明：4-7月是承德市O₃-8h浓度较高的月份,O₃浓度的日变化特征为午后浓度高而夜间浓度低;O₃污染的天气形势为500 hPa受高压脊和偏西气流影响,850 hPa有强暖平流和20℃以上的高温,地面受低压前部和高压后部之间的偏南气流影响;有利于O₃-8h出现高浓度的气象因子为日平均气温大于23℃、日最高气温大于28℃、日平均海平面气压995-1007 hPa、日平均水汽压18-28 hPa、偏南风大于1 m·s^-1。利用气象因子综合评分建立臭氧污染指数,与O₃-8h浓度的相关系数高达0.7553,说明臭氧污染指数能较好地预报臭氧污染天气。  相似文献