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Constraints on sedimentary ages of the Chuanlinggou Formation in the Ming Tombs, Beij.ng, North China Craton: LA-ICP-MS and SHRIMP U–Pb dating of detrital zircons

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Acta Geochimica 2018年第2期37卷 257-280页

作者： j.ng Ding Yuruo Shi Alfred Kroner j. lawford anderson Beij.ng 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, Beij.ng, were dated with the LA-ICP-MS and SHRIMP U-Pb methods. Age spectra of the five samples show a maj.r 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 d： 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 maj.r 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 that the Chuanlinggou Formation in the Ming Tombs District was deposited in a low-energy mud fiat 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： Detrital zircon LA-ICP-MS U-Pb ages SHRIMP Chuanlinggou Formation Ancient sedimentary environment North China Craton

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Zircon SHRIMP U–Pb age of Late j.rassic OIB-type volcanic rocks from the Tethyan Himalaya: constraints on the initial activity time of the Kerguelen mantle plume

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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 j.ngj.e j.n Beij.ng 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 j.rassic magmatism. Whole rock analyses of maj.r 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 j.rassic. 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 j.rassic ZirconSHRIMP U-Pb age Kerguelen mantle plume TethyanHimalaya Lakang Formation

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Petrography and chronology of lunar meteorite Northwest Africa 6950

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Science China(Information Sciences) 2020年第4期63卷 182-194页

作者： Zemin BAO Yuruo SHI j.lawford anderson Allen KENNEDY Zuokai KE Xiangping GU Peizhi WANG Xiaochao CHE Yuelan KANG Huiyi SUN Chen WANG Beij.ng SHRIMP Center Institute of Geology Chinese Academy of Geological Sciences j.hn de Laeter Centre Curtin University Department of Earth and Environment Boston University School of Geosciences and Infophysics Central South University

Northwest Africa(NWA) 6950 is an olivine-gabbro lunar meteorite that has a distinctly different petrographic texture from other lunar basalts. In this contribution, we report the petrography, mineralogy,and U-Pb geochronology of baddeleyite and phosphate in this lunar meteorite and make a comparison with other NWA 773 paired meteorites. NWA 6950 consists mainly of coarse-grained olivine, pyroxene,and plagioclase, with minor ilmenite, chromite, troilite, baddeleyite, taenite, and apatite. The abundant rounded to euhedral olivine has a limited Fo ranging from 68 to 69. Pyroxenes include both augite and pigeonite, with a narrow range of Mg#=71–80, and composition, respectively, EnFsWoand EnFsWo. Plagioclase is mainly anhedral, conforming to the crystal margins of olivine and pyroxene. The plagioclase grains are elongated and several hundreds of microns in length. Raman spectra shows that plagioclase has been transformed into maskelynite, which is very calcic(An87-95) with low sodium and very low potassium(Ab4-9 Or 0.6-3.7). The weighted mean207 Pb/206 Pb ages of baddeleyite and phosphate measured using a sensitive high resolution ion micro probe(SHRIMP II) are 3119 ± 16 Ma(n = 9, MSWD= 2.5)(mean squared weighted deviates, MSWD) and 3119 ± 18 Ma(n = 15, MSWD = 2.1), respectively,giving the crystallization age of the meteorite. NWA 6950 has similar mineral compositions, geochemical characteristics, and an almost identical age of crystallization to the magnesian gabbro of the NWA 773 *** conclude that NWA 6950 and NWA 773 are paired meteorites, which crystallize at ca. 3119 Ma, and represent magmatic activities in the KREEP(potassium(K), rare earth elements(REE) and phosphorus(P) rich lunar material) region of the Moon.

关键词： Northwest Africa 6950 lunar meteorite U-Pb chronology baddeleyite phosphate

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Implementing the GEOSS water strategy: from observations to decisions

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International j.urnal of Digital Earth 2023年第1期16卷 1439-1468页

作者： Richard lawford Sushel Unninayar George j.Huffman Wolfgang Grabs Angélica Gutiérrez Chu Ishida-Watanabe Toshio Koike Morgan State University BaltimoreUSA NASA Goddard Space Flight Center GreenbeltUSA International Water Affairs Federal Institute of HydrologyKoblenz National Oceanic and Atmospheric Administration Silver SpringUSA j.pan Aerospace Exploration Agency Tsukuba International Centre for Water Hazard and Risk Management Tsukuba

In 2014,The GEOSS Water Strategy–From Observations to Decisions was published and steps were taken to implement the Strategy’s *** Strategy highlighted priority areas where the application of Earth observations to water research and water management decisions would have significant scientific and societal *** article reviews the implementation of the Strategy’s recommendations over the past eight *** a review of the Strategy’s assessment of the needs for water observations and their applications,it then reviews actions taken in response to the Strategy’s recommendations in its four maj.r themes:improved data acquisition for Essential Water Variables,research and product development,interoperability,and capacity *** highlights significant achievements in the implementation of the Strategy including some motivated by factors beyond this Strategy,reviews actions taken by participating agencies and programs for each of the main themes and summarizes the remaining challenges in achieving the Strategy’s full *** article not only is an update for the Water Community regarding the GEOSS Water Strategy,but it is also an example of how other communities could develop and promulgate a set of strategic recommendations,monitor progress,and carry out assessments of their effectiveness.

关键词： Earth observations water essential water variables research interoperability capacity development

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