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An origin of the along-arc compositional variation in the Izu-Bonin arc system

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Geoscience Frontiers 2020年第5期11卷 1621-1634页

作者： Kathryn Durkin Paterno R.Castillo Susanne M.Straub Natsue Abe Yoshihiko Tamura Quanshu Yan Scripps Institution of Oceanography UCSD9500 Gilman DriveLa JollaCA92093-0212USA lamont-doherty earth observatory Columbia Univ.61 US-9WPalisadesNY10964USA Japan Agency for Marine-earth Science and Technology(JAMSTEC) 2-15 Natsushima-choJapan Key Laboratory of Marine Sedimentary and Environmental Geology The First Institute of OceanographyState Oceanic AdministrationQingdao 266061China

The Izu-Bonin arc system is sediment-poor(~400 m thick with no accretionary prism)and,therefore,the influence of the altered oceanic crust(AOC)is most likely the source of the documented along-arc lava compositional variations,especially in Pb ***-Bonin arc lava geochemistry suggests an influx of subduction component from an Indian-type ***,samples drilled from the western Pacific geochemical reference site at Integrated Ocean Drilling Program Site 1149 implies subduction of a Pacific-type *** solve the apparent discrepancy of slab input versus arc output in this arc system,samples of the AOC were dredged from vertical fault scarps of the subducting Pacific Plate along a transect from 27.5°N to 34.50 *** range from tholeiitic to mildly alkalic mid-ocean ridge basalts as well as trachybasalts,basaltic trachyandesites,tephrites,and *** ratios also exhibit a range of values(87Sr/86Sr=0.70282-0.70673,143 Nd/144 Nd=0.512552-0.513174,206Pb/204 Pb=18.43-20.00,207 Pb/204 Pb=15.40-15.67,208Pb/204Pb=37.75-39.55).Our results suggest that there is a geochemical variation in the AOC that is neither completely due to seawater or hydrothermal alteration,nor to petrogenetic ***,this variation is the result of the Pacific-Izanagi Ridge system tapping into a heterogeneous,plume-polluted mantle source during the Mid-Cretaceous volcanic *** observed Pacific-type AOC is not responsible for the Indian-type Pb isotopic signature of Izu-Bonin arc *** leads us to propose an alternative scenario where the Izu-Bonin arc lava Indian-type Pb isotopic signature originates from slab-derived fluids interacting and adsorbing Pb from an Indian-type mantle wedge through zone-refining.

关键词： Izu-Bonin AOC Pb-isotopes Indian-type Zone-refining

Ecological controls on biogeochemical fluxes in the western Antarctic Peninsula studied with an inverse foodweb model

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Advances in Polar Science 2015年第2期26卷 122-139页

作者： Hugh W.Ducklow S.C.Doney S.F.Sailley lamont-doherty earth observatory Columbia University Woods Hole Oceanographic Institution Plymouth Marine Laboratory

Sea ice in the western Antarctic Peninsula （WAP） region is both highly variable and rapidly changing. In the Palmer Station region, the ice season duration has decreased by 92 d since 1978. The sea-ice changes affect ocean stratification and freshwater balance and in turn impact every component of the polar marine ecosystem. Long-term observations from the WAP nearshore and offshore regions show a pattern of chlorophyll （Chl） variability with three to five years of negative Chl anomalies interrupted by one or two years of positive anomalies （high and low Chl regimes）. Both field observations and results from an inverse food-web model show that these high and low Chl regimes differed significantly from each other, with high primary productivity and net community production （NCP） and other rates associated with the high Chl years and low rates with low Chl years. Gross primary production rates （GPP） averaged 30 mmolC.m^-2.d^-1 in the low Chl years and 100 mmolC.m-2.d1 in the high Chl years. Both large and small phytoplankton were more abundant and more productive in high Chl years than in low Chl years. Similarly, krill were more important as grazers in high Chl years, but did not differ from microzooplankton in high or low Chl years. Microzooplankton did not differ between high and low Chl years. Net community production differed significantly between high and low Chl years, but mobilized a similar proportion of GPP in both high and low Chl years. The composition of the NCP was uniform in high and low Chl years. These results emphasize the importance of microbial components in the WAP plankton system and suggest that food webs dominated by small phytoplankton can have pathways that funnel production into NCP, and likely, export.

关键词： ecological controls biogeochemical food-web model

地下水中天然砷的迁移:以高砷地区中低砷含水层为例(英文)

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中国地质 2010年第3期37卷 723-729页

作者： Yan ZHENG School of earth and Enviromental Sciences Queens College City University of New York Flushing NY 11367 USA lamont-doherty earth observatory of columbia university Palisades NY 10964 USA

研究表明饮用水中微小数量的砷会对人类健康产生不利影响。世界上居住在贫穷地区的人数超过了100万,目前他们正直接饮用来自含水层中砷离子含量(>10μg/L)非安全标准的地下水。砷有时称为毒中之王,在水环境中常常以五价氧化物形式出现。... 详细信息

研究表明饮用水中微小数量的砷会对人类健康产生不利影响。世界上居住在贫穷地区的人数超过了100万,目前他们正直接饮用来自含水层中砷离子含量(>10μg/L)非安全标准的地下水。砷有时称为毒中之王,在水环境中常常以五价氧化物形式出现。自2000年以来,许多国家开始执行更为严格的10μg/L(WHO认可的居民安全饮水标准)饮用水标准,可以确定地说,在世界范围内的饮用水中检测到砷的情况越来越多。亚洲地区砷中毒的人数比世界其他地区总和还多。最受影响的地区位于南亚和东南亚富砷带,环绕恒河—雅鲁藏布江—梅克纳河三角洲及恒河平原上游的冲洪积扇含水层、红河三角洲、湄公河和伊洛瓦底江;在中国境内包括内蒙黄河冲积盆地,山西大同盆地、新疆准噶尔盆地,其中的地下水富含砷和氟化物而引发砷中毒和氟中毒。尽管还未完全掌握其中的水文地质及生物地球化学作用的详细过程,但对大多数沉积介质含水层,在还原条件下砷离子容易从沉积介质转移到地下水中。孟加拉研究实例表明地质时期尺度的冲刷降低了沉积介质中的As和有机物含量从而形成低砷地下水。这一认识为孟加拉国的降砷策略提供了科学指导,是未来水文学,矿物学,地质学和生物地球化学方面很有意义的研究方向,并有利于地砷病区低砷地下水的可持续利用。

关键词：砷地下水地球化学

Evolution of subcontinental lithospheric mantle beneath eastern China:Re-Os isotopic evidence from mantle xenoliths in Paleozoic kimberlites and Mesozoic basalts

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Evolution of subcontinental lithospheric mantle beneath east...

Difference in Tree Growth Responses to Climate at the Upper Treeline: Qilian Juniper in the Anyemaqen Mountains

中国科学院地质与地球物理研究所2008学术年会

作者： Steven L.Goldstein lamont-doherty earth observatory and Department of earth and Environmental Sciences Columbia University61 Rt.9WPalisadesNY 10964USA

The ages of subcontinental lithospheric mantle beneath the North China and South China cratons are less well-constrained than the overlying *** report Re-Os isotope systematics of mantle xenoliths entrained in Paleozoic kimberlites and Mesozoic basalts from eastern *** xenoliths from the Fuxian and Mengyin Paleozoic diamondiferous kimberlites in the North China Craton give Archean Re depletion ages of 2.6-3.2 Ga and melt depletion ages of 2.9-3.4 *** obvious differences in Re and Os abundances,Os isotopic ratios and model ages are observed between spinel-facies and garnet-facies peridotites from both kimberlite *** Re-Os isotopic data,together with the PGE concentrations,demonstrate that beneath the Archean continental crust of the eastern North China Craton,Archean lithospheric mantle of spinel- to diamond-facies existed without apparent compositional stratification during the *** Mesozoic and Cenozoic basalt-borne peridotite and pyroxenite xenoliths,on the other hand,show geochemical features indicating metasomatic enrichment,along with a large range of the Re-Os isotopic model ages from Proterozoic to *** features indicate that lithospheric transformation or refertilization through melt-peridotite interaction could be the primary mechanism for compositional changes during the Phanerozoic,rather than delamination or thermal-mechanical erosion,despite the potential of these latter processes to play an important role for the loss of garnet-facies mantle.A fresh garnet lherzolite xenolith from the Yangtze Block has a Re depletion age of～1.04 Ga,much younger than overlying Archean crustal rocks but the same Re depletion ages as spinel lherzolite xenoliths from adjacent Mesozoic basalts,indicating Neoproterozoic resetting of the Re-Os system in the South China Craton.

关键词： Eastern China Mantle xenoliths Re-Os isotopes PGEs Subcontinental lithospheric mantle Re depletion ages

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Journal of Integrative Plant Biology 2008年第8期50卷 982-990页

作者： Jianfeng Peng Xiaohua Gou Fahu Chen Jinbao Li Puxing Liu Yong Zhang Keyan Fang Center for Arid Environment and Paleoclimate Research (CAEP) Key Laboratory of Westem China's Environment Systems MOE Lanzhou University Lanzhou 730000 China Institute of Resource and Environment Henan University Kaifeng 475004 China Tree-Ring Laboratory Lamont-Doherty Earth Observatory Columbia University NY 10964 USA College of Geography and Environment Sciences Northwest Normal University Lanzhou 730070 China

Three ring-width chronologies were developed from Qilian Juniper （Sabina przewalskii Kom.） at the upper treeline along a west-east gradient in the Anyemaqen Mountains. Most chronological statistics, except for mean sensitivity （MS）, decreased from west to east. The first principal component （PC1） Ioadings indicated that stands in a similar climate condition were most important to the variability of radial growth. PC2 Ioadings decreased from west to east, suggesting the difference of tree-growth between eastern and western Anyemaqen Mountains. Correlations between standard chronologies and climatic factors revealed different climatic influences on radial growth along a west-east gradient in the study area. Temperature of warm season （July-August） was important to the radial growth at the upper treeline in the whole study area. Precipitation of current May was an important limiting factor of tree growth only in the western （drier） upper treeline, whereas precipitation of current September limited tree growth in the eastern （wetter） upper treeline. Response function analysis results showed that there were regional differences between tree growth and climatic factors in various sampling sites of the whole study area. Temperature and precipitation were the important factors influencing tree growth in western （drier） upper treeline. However, tree growth was greatly limited by temperature at the upper treeline in the middle area, and was more limited by precipitation than temperature in the eastern （wetter） upper treeline.

关键词： climate-growth correlations dendrochronology Qilian juniper treeline

Effect of Freshwater Influx on Phytoplankton in the Mandovi Estuary (Goa, India) during Monsoon Season: Chemotaxonomy

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Journal of Water Resource and Protection 2013年第3期5卷 349-361页

作者： Sushma G. Parab S. G. Prabhu Matondkar Helga do R. Gomes Joaquim I. Goes lamont doherty earth observatory at columbia university New York USA National Institute of Oceanography Dona Paula Goa India

The Mandovi estuary is a prominent water body that runs along the west coast ofIndia. It forms an estuarine network with the adjacent Zuari estuary, connected via the Cumbharjua canal. The physico-chemical conditions seen in the Mandovi estuary are influenced by two factors: the fresh water runoff during the monsoon season (June-September) and the tidal influx of coastal seawater during the summer (October to May) season. However, the effects of monsoon related changes on the phytoplankton of the Mandovi estuary are not yet fully understood. An attempt to understand the same has been made here by applying the process of daily sampling at a fixed station throughout the monsoon season. It was noticed that the onset of the monsoon is responsible for an increase in nitrate levels upto 26 μM from a (chl a) as high as 14 μg·L-1 during the same period. The phytoplankton population was observed through both chemotaxonomy and microscopy and was found to be composed mainly of diatoms. CHEMTAX analysis further uncovers the presence of several other groups of phytoplankton, the presence of which is yet to be reported in many other tropical estuaries. It includes chrysophytes, cyanobacteria, prasinophytes, prymnesiophytes and chlorophytes. The appearance of phytoplankton groups at various stages of the monsoon was recorded, and this data is discussed in relation to environmental changes in the Mandovi estuary during the monsoon season.

关键词： Phytoplankton Pigment Analysis Monsoon Freshwater Runoff CHEMTAX

Late Miocene-Pliocene development of Asian aridification as recorded in the Red-earth Formation in northern China

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Late Miocene-Pliocene development of Asian aridification as ...

Origin and Evolution of Ultramafic Rocks along the Sagaing Fault, Myanmar

中国科学院地质与地球物理研究所2004学术年会

作者： Pierre E.Biscaye Tungsheng Liu lamont-doherty earth observatory of columbia university PO Box 1000PalisadesNY 10964-8000.USA Institute of Geology and Geophysics Chinese Academy of Sciences

In northern China,the Late Miocene-Pliocene Hipparion Red-earth Formation in the eastern Loess Plateau fills a gap of climate records between the well-known loess-soil sequences of the last 2.6 Ma and the Miocene loess-soil sequences from the western Loess *** studies on type sections indicate that a major part of the Red-earth Formation is also of windblown origin,covering the period from～7-8 to～2.6 Ma *** the eolian dust deposited in the region originated from the Asian desert lands,the Red-earth must contain a record of the aridification history of the Asian *** this study,the Xifeng type section in the eastern Loess Plateau is studied to assess the development of Asian aridification during Late Miocene-Pliocene *** dust deposition continued at the central Loess Plateau since-6.2 Ma BP,indicating that sizable desert lands in the interior of Asia and the Asian winter monsoon must have been constantly maintained during Late Miocene-Pliocene time,and were able to provide a significant amount of eolian *** aridity in the source areas was stronger from～6.2 to～5 Ma BP and weaker from～5 to～3.6 Ma *** major aridification steps are observed at-3.6 and～2.6 Ma BP,*** intensification of eolian deposition at-3.6 Ma BP is synchronous with a suggested uplift of portions of the Tibetan *** general aridification history is also highly consistent with the ongoing high-latitude cooling and the consequent expansion of Arctic sea-ice/ice sheets during this *** results therefore suggest that both Tibetan uplift and ice-building processes in the northern hemisphere were two prominent driving forces behind the long-term desertification in the interior of Asia during Late Miocene and Pliocene time.

关键词： East Asian aridification Miocene-Pliocene eolian deposition Winter monsoon Hipparion Red-earth Formation

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Journal of earth Science 2023年第1期34卷 122-132页

作者： Tomoaki Morishita Hnin Min Soe Hla Htay Than Htut Lwin Juan Miguel Guotana Akihiro Tamura Tomoyuki Mizukami Khin Zaw 无 Faculty of Geosciences and Civil Engineering Kanazawa UniversityKanazawa920-1192Japan lamont-doherty earth observatory Columbia UniversityPalisadesNY10964USA Volcanoes and earth’s Interior Research Center Japan Agency for Marine-Earth Science and Technology2-15 NatsushimaKanagawa237-0061Japan Geology Department University of MandalayMandalay05092Myanmar Geology Department Dagon UniversityNorth Dagon11422Myanmar Taunggoke Degree College TaunggokeTaunggoke Township07161Myanmar Graduate School of Natural Science and Technology Kanazawa UniversityKanazawaIshikawa920-1192Japan CODES ARC Centre of Excellence in Ore Deposits University of TasmaniaTasmania7001Australia

The active Sagaing fault in Myanmar defines the boundary between the Indian Plate and the Eurasian Plate and causes seismic damage in the major cities of Myanmar. Small bodies of serpentinite occur along the fault. We for the first time investigated the highly sheared serpentinite bodies in the Sheinmagar area and Yega Inn area along the Sagaing fault. Extensively sheared/brecciated serpentinites and related rocks, such as talc and/or chlorite-bearing rocks contains small rock fragments of serpentinites. Serpentine texture and mineral chemistry indicate that the protolith of these serpentinites were mainly harzburgite with minor amounts of dunite, some of which are cut by gabbroic veins. No shape-preferred orientation of the antigorite is present, indicating that the serpentinization was occurred under relatively static conditions. Protolith and serpentine minerals are similar to those of the jadeitite-bearing serpentinites in the north of the Sagaing fault(the Jade Mine belt). Chemical variations of spinels in the studied area are within the compositional range of forearc peridotites and those in the mantle section of nearby ophiolites. After the formation of antigorite serpentinite under static conditions, these serpentinites were subsequently, but locally deformed, probably due to the activity of the Sagaing fault, resulting in the formation of serpentinite schist/brecciated rock. The presence of the less-deformed antigorite serpentinite in the sheared/brecciated zone indicates the strain localization mainly along the surrounding serpentine-talc(±chlorite) schistose rocks, which is probably formed by the reaction between serpentinite and country rocks. Further studies are needed to better understand whether the distribution of serpentinized peridotites cause variations in the activity of the Sagaing fault.

关键词： Sagaing fault serpentinite deformation ophiolite

RECONSTRUCTION OF WIND STRESS ANOMALIES SIMULATED BY AN AGCM USING SVD TECHNIQUE

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Acta meteorologica Sinica 1996年第3期10卷 257-269页

作者：倪允琪 S.E.Zebiak M.A.Cane L.Marx Department of Atmospheric Sciences Nanjing University.Nanjing 210093 lamont-doherty earth observatory of columbia university.palisades NY 10964USA Center for Ocean-Land-Atmosphere Studies.Calverton MD 20705-3106USA

Systematic errors in the COLA R15 AGCM are analyzed by the SVD *** order to remove or reduce this kind of error source and reduce climate drift in coupled runs a way in which the wind stress anomalies simulated by an AGCM are reconstructed is proposed by using SVD anal- *** results show that not only wind stress anomalies simulated by an AGCM are obviously improved by reconstructed wind stress anomalies but also this reconstruction has a func- tion of a low-pass time filter,as a result,response of the ZC ocean model to reconstructed wind stress anomalies is more realistic than that of simulated wind stress anomalies by an *** this paper,application of the hybrid couple ocean-atmosphere model is further discussed.

关键词： reconstruction wind stress anomaly SVD technique climate signal climate change