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   

地缘政治视角下中亚“颜色革命”易发程度分析     

李希雅  王礼茂 《世界地理研究》2019,28(6):42-49

基于地缘政治视角，分析本世纪初发生在原苏联地区“颜色革命”的诱发因素，认为美国根据其地缘战略格局对“颜色革命”发生地存在一定程度的主观选择性，国家内部经济、政治、社会等层面的矛盾也同样作为发生背景。在中亚地缘格局动态分析的基础上，结合中亚五国形势，从时间和空间双重维度对中亚地区未来发生“颜色革命”的可能性进行识别与评判，得出1) 整体来看，中亚近期内爆发“颜色革命”可能性较小，但从长远来看不能掉以轻心。2)土、乌未来稳定可期，塔、吉、哈需谨防“颜色革命”卷土重来。  相似文献   

利用InSAR资料反演宁洱Ms6.4地震震源参数及库仑应力变化     

陈晨月  冯光财  高华  杨怀宁 《大地测量与地球动力学》2019,39(3):295-301

首先利用ALOS PALSAR数据，通过D-InSAR技术获取2007-06-03云南宁洱MS6.4地震的同震形变场，然后基于Okada弹性半空间位错模型反演该地震的断层几何以及精细滑动分布，最后计算宁洱地震后周边断层的静态库仑应力变化。结果表明，形变主要集中在西盘，最大视线向形变量为51.6 cm；反演得到的震源位置为23.05°N、101.02°E，深度3 km，断层走向145°，倾向49.5°，平均滑动角153°，发震断层为NNW向普洱断裂，断层活动以右旋走滑为主，兼具逆冲分量；断层面最大滑动量为1.2 m，反演得到的震级为MW619。基于库仑应力场发现，磨黑断裂处于库仑应力增加区域，而2014年景谷地震位于负值区域。结合实地考察资料和反演结果表明，宁洱地震为浅源地震，但断层并未出露地表。  相似文献   

基于GPS和水准数据的微粒群算法联合反演祁连山北缘断裂三维滑动速率     

刘杰 《大地测量与地球动力学》2019,39(9):906-909

将微粒群算法与位错理论模型相结合，采用中国地壳运动观测网络提供的青藏高原地区2001~2004年GPS测量数据和2000~2006年水准测量数据，通过常规定权和附有相对权比的方法对祁连山北缘断裂的三维滑动速率进行联合反演，并与蚁群算法反演结果进行对比。结果表明，微粒群算法收敛速度快、稳定性高，结合经典位错理论模型，是一种可以有效求解断层三维滑动速率反演问题的优化算法，在大地测量反演领域极具应用潜力。  相似文献   

BDS卫星差分码偏差稳定性分析及其短期预报     

梅登奎  闻德保 《大地测量与地球动力学》2020,40(7):746-750

利用MGEX(multi-GNSS experiment)发布的BDS卫星差分码偏差(differential code bias, DCB)产品，比较分析不同太阳活动水平下BDS卫星DCB产品的稳定性变化特性，并采用差分自回归移动平均(auto-regressive integrated moving average, ARIMA)时间序列预测模型，实现不同太阳活动水平下BDS卫星DCB的短期预报。结果表明，在太阳活动高年，BDS卫星DCB日解值稳定度、月稳定性均明显低于太阳活动低年，且不同卫星星座类型的BDS卫星DCB稳定性也存在差异；ARIMA时间序列预报结果与MGEX发布值符合程度较好，优于多项式拟合法预测结果。  相似文献   

Paleoproterozoic volcanic rocks in the southern margin of the North China Craton,central China:Implications for the Columbia supercontinent   总被引：1，自引：0，他引：1  

Changming Wang  Xinyu He  Emmanuel John M.Carranza  Chengmin Cui 《地学前缘(英文版)》2019,10(4):1543-1560

The volcanic rocks of the Xiong'er Group are situated in the southern margin of the North China Craton(NCC).Research on the Xiong er Group is important to understand the tectonic evolution of the NCC and the Columbia supercontinent during the Paleoproterozoic.In this study,to constrain the age of the Xiong'er volcanic rocks and identify its tectonic environment,we report zircon LA-ICP-MS data with Hf isotope,whole-rock major and trace element compositions and Sr-Nd-Pb-Hf isotopes of the volcanic rocks of the Xiong'er Group.The Xiong'er volcanic rocks mainly consist of basaltic andesite,andesite.dacite and rhyolite,with minor basalt.Our new sets of data combined with those from previous studies indicate that Xiong'er volcanism should have lasted from 1827 Ma to 1746 Ma as the major phase of the volcanism.These volcanics have extremely low MgO.Cr and Ni contents,are enriched in LREEs and LILEs but depleted in HFSEs(Nb,Ta,and Ti),similar to arc-related volcanic rocks.They are characterized by negative zircon ε_(Hf)_(t) values of-17.4 to 8.8,whole-rock initial ~(87)Sr/~(86)Sr values of 0.7023 to 0.7177 andε_(Nd)(t) values of-10.9 to 6.4.and Pb isotopes(~(206)Pb/~(204)Pb =14.366-16.431,~(207)Pb/~(204)Pb =15.106-15.371,~(208)Pb/~(204)Pb= 32.455-37.422).The available elemental and Sr-Nd-Pb-Hf isotope data suggest that the Xiong'er volcanic rocks were sourced from a mantle contaminated by continental crust.The volcanic rocks of the Xiong'er Group might have been generated by high-degree partial melting of a lithospheric mantle that was originally modified by oceanic subduction in the Archean.Thus,we suggest that the subduction-modified lithospheric mantle occurred in an extensional setting during the breakup of the Columbia supercontinent in the Late Paleoproterozoic,rather than in an arc setting.  相似文献   

浅析广安华蓥山区山水林田湖综合治理措施——以高顶山矿区为例     

李飞  裴云婧  王维  李德星  张春茂 《四川地质学报》2020,40(1):80-85

高顶山矿区位于广安华蓥市城区东南约5km处。长期的采矿活动,导致区内矿山地质环境问题突出,严重影响华蓥山地区人民的生命财产安全。矿山地质环境问题亟待解决。本文通过分析区内主要存在的矿山地质环境问题,提出通过矿山地质灾害、矿山土地恢复、矿山地形地貌景观恢复治理,河道综合整治、道路修复、生态保育、产业提升等措施;消除安全隐患,保障区内人民生命财产安全;改善生态环境,实现华蓥山地区生态环境全面恢复,生态环境质量提升,提高环境承载力,实现区内"山青、水秀、林美、田良"的目标。并对区内的产业转型升级进行了探讨,提出将高顶山矿区建设成具有科普和教育价值的旅游景观目的地;利用矿区独具特色工业人文景观和别致的自然景观,将高顶山矿区建设成集"科普、休闲、康养、户外、探秘"五大功能于一体的矿山公园,推动矿业经济转型升级,促进产业结构转型和经济社会可持续发展。  相似文献   

Tropical cyclones and multiscale climate variability: The active western North Pacific Typhoon season of 2018     

Wu  Liang  Zhang  Hongjie  Feng  Tao  Tang  Yulian 《中国科学:地球科学(英文版)》2020,63(1):1-11

The 2018 typhoon season in the western North Pacific(WNP) was highly active, with 26 named tropical cyclones(TCs) from June to November, which exceeded the climatological mean(22) and was the second busiest season over the past twenty years. More TCs formed in the eastern region of the WNP and the northern region of the South China Sea(SCS). More TCs took the northeast quadrant in the WNP, recurving from northwestward to northward and causing heavy damages in China's Mainland(69.73 billion yuan) in 2018. Multiscale climate variability is conducive to an active season via an enhanced monsoon trough and a weakened subtropical high in the WNP. The large-scale backgrounds in 2018 showed a favorable environment for TCs established by a developing central Pacific(CP) El Ni?o and positive Pacific meridional mode(PMM)episode on interannual timescales. The tropical central Pacific(TCP) SST forcing exhibits primary control on TCs in the WNP and large-scale circulations, which are insensitive to the PMM. During CP El Ni?o years, anomalous convection associated with the TCP warming leads to significantly increased anomalous cyclonic circulation in the WNP because of a Gill-type Rossby wave response. As a result, the weakened subtropical high and enhanced monsoon trough shift eastward and northward, which favor TC genesis and development. Although such increased TC activity in 2018 might be slightly suppressed by interdecadal climate variability, it was mostly attributed to the favorable interannual background. In addition, high-frequency climate signals,such as intraseasonal oscillations(ISOs) and synoptic-scale disturbances(SSDs), interacted with the enhanced monsoon trough and strongly modulated regional TC genesis and development in 2018.  相似文献   

2015年台风“彩虹”过境后下山冷急流引起的南海北部海域异常海面降温   总被引：1，自引：0，他引：1  

石雨鑫  谢玲玲  郑全安  张书文  李明明  李君益 《海洋学报(英文版)》2019,38(5):62-75

This study deals with a unusual cooling event after Typhoon Mujigea passed over the northern South China Sea(SCS) in October 2015. We analyze the satellite sea surface temperature(SST) time series from October 3 to 18,2015 and find that the cooling process in the coastal ocean had two different stages. The first stage occurred immediately after typhoon passage on October 3, and reached a maximum SST drop of –2℃ on October 7 as the usual cold wake after typhoon. The second stage or the unusual extended cooling event occurred after 7d of the typhoon passage, and lasted for 5d from October 10 to 15. The maximum SST cooling was –4℃ and occurred after 12d of typhoon passage. The mechanism analysis results indicate that after landing and moving northwestward to the Yunnan-Guizhou Plateau(YGP), Typhoon Mujigea(2015) met the westerly wind front on October 5. The lowpressure and positive-vorticity disturbances to the front triggered meridional air flow and low-pressure trough,thus induced a katabatic cold jet downward from the Qinghai-Tibet Plateau(QTP) passing through the YGP to the northwestern SCS. The second cooling reached the maximum SST drop 4d later after the maximum air temperature drop of –9℃ on October 11. The simultaneous air temperature and SST observations at three coastal stations reveal that it is this katabatic cold jet intrusion to lead the unusual SST cooling event.  相似文献   

辽宁省积雪对自动气象站观测地气温差的影响     

朱玲  顾正强  龚强  晁华  李杨  徐红  周晓宇  沈历都  蔺娜 《冰川冻土》2019,41(2):293-303

利用1971—2016年辽宁省61个气象站气温、地表温度、积雪日数和积雪深度资料，分析了积雪的保温作用及其对地气温差的影响。结果表明：更换自动站前后地表温度观测方式的差异导致地气温差显著增大，地气温差的增大程度受所在区域积雪日数、积雪深度的影响显著。在积雪期较长、积雪较厚的地区，积雪引起反照率增大，使得雪面温度降低，导致雪气温差减小，而雪的保温作用使得地气温差显著增大。因此，更换自动站前地（雪）气温差与积雪日数呈显著负相关，而更换自动站后地气温差与积雪日数呈显著正相关。各台站之间地气温差随积雪深度的变化系数差异较大，为0.045~0.858 ℃?cm^-1，在年平均积雪日数＜40 d、年平均极端积雪深度＜10 cm的区域，积雪的保温作用随积雪深度增大而显著增大；在年平均积雪日数＞40 d、年平均极端积雪深度＞10 cm的区域，10 cm以下的积雪对土壤保温作用随积雪深度增大显著，当积雪深度＞10 cm后，其保温作用随积雪深度增大的幅度明显减小。  相似文献