Testing commonly used X‐ray fluorescence core scanning‐based proxies for organic‐rich lake sediments and peat          下载免费PDF全文

Sakonvan Chawchai  Malin E. Kylander  Akkaneewut Chabangborn  Ludvig Lwemark  Barbara Wohlfarth 《Boreas: An International Journal of Quaternary Research》2016,45(1):180-189

X‐ray fluorescence (XRF) core scanning has become widely available for geological studies during the last decade. The data obtained from XRF core scanning, however, may be strongly influenced by the amount of organic matter, water content, density and porosity of the sediment matrix. In this study we discuss the usefulness of XRF core scanning to distinguish different kinds of organic‐rich sediments and peat based on examples from tropical Lakes Kumphawapi and Nong Leng Sai in Thailand. We examined how sedimentary factors influence XRF core scanning analyses by comparing elemental and scattering ratios to lithological changes and quantitative LOI, TOC, biogenic silica (BSi) and grain‐size values. Our comparison suggests that the (inc/coh) scattering ratio is of limited use as an indicator for variations in LOI and TOC in peaty gyttja or peat. In Lake Kumphawapi's sediments, Si/Ti ratios reflect clastic input associated with grain‐size variations rather than BSi contents. The Ti‐normalized ratios of Si, Zr, Sr, K and Rb are linked to mineral input and associated grain‐size variations. We conclude that XRF core scanning of organic‐rich tropical lake sediments and peat is useful to infer palaeoenvironmental conditions. However, XRF core scanning data does not stand‐alone and needs to be underpinned by additional proxies.  相似文献   

Geomagnetic lunar analysis by least-squares     

S. R. C. Malin  D. M. Schlapp 《Geophysical Journal International》1980,60(3):409-418

Summary. A simple and accurate method is presented for the determination of lunar and solar harmonic terms present in a series of geomagnetic data. It is based on least-squares and incorporates a direct means for determining the confidence limits. The method is tested by applying it to a series of artificially generated data, and comparing the results both with the true answers and with results obtained using existing methods.  相似文献   

A Model of the Geomagnetic Field at Epoch 1975     

D. R. Barraclough  J. M. Harwood  B. R. Leaton  S. R. C. Malin 《Geophysical Journal International》1975,43(3):645-659

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The new solar system: Twenty separately authored chapters,edited by J. Kelly Beatty,Brian O'Leary,and Andrew Chaikin,with an introduction by Carl Sagan,Cambridge University Press and Sky Publishing Corporation,Cambridge, Massachussetts, 1981. 224 pp., ca. $20.00     

Michael C. Malin 《Icarus》1982,51(3):668-669

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A multivariate assessment of coastal eutrophication. Examples from the Gulf of Finland, northern Baltic Sea   总被引：1，自引：0，他引：1  

Lundberg C  Lönnroth M  von Numers M  Bonsdorff E 《Marine pollution bulletin》2005,50(11):1185-1196

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Induction in arbitrarily shaped oceans –VI. Oceans of variable depth     

D. Beamish  R. C. Hewson-Browne  P. C. Kendall  S. R. C. Malin  D. A. Quinney 《Geophysical Journal International》1983,75(2):387-396

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Book reviews     

Alexander Zaporozec  Alexander Zaporozec  Malin Falkenmark 《GeoJournal》1981,5(5):516-516

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Biotransformation enzyme activities and PCDD/PCDF levels in pike caught in a Swedish Lake     

Lars Frlin  Lennart Balk  Malin Celander  Sture Bergek  Maria Hjelt  Christoffer Rappe  Cynthia de Wit  Bo Jansson 《Marine environmental research》1992,34(1-4)

Recently, analysis of organochlorines in sediment and in pike from Lake Vänern, Sweden, showed a north-south gradient of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). In the present study, good correlations were found between muscle 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents and liver ethoxyresorufin-O-deethylase (EROD) activities (and P4501A levels) in pike caught at three sampling sites along the north-south gradient in the lake. This comparison between tissue levels of PCDD/PCDF and EROD activity (and P4501A) may indicate that TCDD or structural analogs could be responsible for the observed induction of the pike P450 system. It must, however, be taken into account that the analysed contaminants often do not appear alone but are, rather, accompanied by a range of other substances which may be inducers or antagonists.  相似文献   

Regional operational and environmental performance evaluation in China: non-radial DEA methodology under natural and managerial disposability     

Malin Song  Guijun Zhang  Kuangnan Fang  Jing Zhang 《Natural Hazards》2016,84(1):243-265

In this article, we used a non-radial DEA under natural and managerial disposability to measure the unified efficiency of 30 administrative regions in China and then evaluated their operational and environmental performances. We proposed the performance progress unified index (PPUI) based on the non-radial DEA methodology in a time horizon under natural and managerial disposability with a crossover to measure the performance variety of DMUs. The results of the unified efficiency measured under natural and managerial disposability showed that both operational and environmental performance in eastern China were the highest among the three regions during 2000–2011. The PPUIs under natural and managerial disposability indicated that the operational and environmental performance of the three regions improved during 2000–2011, and the rate of operational and environmental performance of eastern China was higher than the other two regions.  相似文献   

Interpreting granulite facies events through rare earth element partitioning arrays          下载免费PDF全文

R. J. M. Taylor  C. Clark  S. L. Harley  A. R. C. Kylander‐Clark  B. R. Hacker  P. D. Kinny 《Journal of Metamorphic Geology》2017,35(7):759-775

The use of rare earth element (REE) partition coefficients is an increasingly common tool in metamorphic studies, linking the growth or modification of accessory mineral geochronometers to the bulk silicate mineral assemblage. The most commonly used mineral pair for the study of high‐grade metamorphic rocks is zircon and garnet. The link from U–Pb ages provided by zircon to the P–T information recorded by garnet can be interpreted in relation to experimental data. The simplistic approach of taking the average REE abundances for zircon and garnet and comparing them directly to experimentally derived partition coefficients is imperfect, in that it cannot represent the complexity of a natural rock system. This study describes a method that uses all the zircon analyses from a sample, and compares them to different garnet compositions in the same rock. Using the most important REE values, it is possible to define zircon–garnet equilibrium using an array rather than an average. The array plot describes partitioning between zircon and garnet using D_Yb and D_Yb/D_Gd as the defining features of the relationship. This approach provides far more sensitivity to mineral reactions and diffusional processes, enabling a more detailed interpretation of metamorphic history of the sample.  相似文献