نتایج جستجو برای: lead isotopes

تعداد نتایج: 362795  

Journal: :Environmental Health Perspectives 1999
B L Gulson K R Mahaffey C W Jameson N Patison A J Law K J Mizon M J Korsch D Pederson

We measured high precision lead isotope ratios and lead concentrations in blood, urine, and environmental samples to assess the significance of diet as a contributing factor to blood and urine lead levels in a cohort of 23 migrant women and 5 Australian-born women. We evaluated possible correlations between levels of dietary lead intake and changes observed in blood and urine lead levels and is...

2008
S. Q. Zhang J. Meng S. - G. Zhou J. Y. Zeng

Based on the systematic investigation of the data available for A ≥ 40, a Z 1/3 dependence for the nuclear charge radii is shown to be superior to the generally accepted A 1/3 law. A delicate scattering of data around R c /Z 1/3 is infered as owing to the isospin effect and a linear dependence of R c /Z 1/3 on N/Z (or (N − Z)/2) is found. This inference is well supported by the microscopic Rela...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2009
Bing Shen Benjamin Jacobsen Cin-Ty A Lee Qing-Zhu Yin Douglas M Morton

Continental crust is too Si-rich and Mg-poor to derive directly from mantle melting, which generates basaltic rather than felsic magmas. Converting basalt to more felsic compositions requires a second step involving Mg loss, which is thought to be dominated by internal igneous differentiation. However, igneous differentiation alone may not be able to generate granites, the most silicic endmembe...

1998
J. C. Lassiter E. H. Hauri

Isotopic heterogeneity in Hawaiian shield lavas reflects the presence of two distinct recycled components in the Hawaiian plume, both from the same packet of recycled oceanic lithosphere. Radiogenic Os-isotopes and anomalously heavy oxygen-isotopes in Koolau lavas reflect melt generation from recycled oceanic crust plus pelagic sediment. In contrast, Kea lavas have unradiogenic Os-isotopes but ...

Journal: :Environmental research 2014
Myra E Finkelstein Zeka E Kuspa Alacia Welch Curtis Eng Michael Clark Joseph Burnett Donald R Smith

Lead poisoning is preventing the recovery of the critically endangered California condor (Gymnogyps californianus) and lead isotope analyses have demonstrated that ingestion of spent lead ammunition is the principal source of lead poisoning in condors. Over an 8 month period in 2009, three lead-poisoned condors were independently presented with birdshot embedded in their tissues, evidencing the...

Journal: :Environmental pollution 2005
Vincent Roussiez Wolfgang Ludwig Jean-Luc Probst André Monaco

This paper presents an attempt to reach natural background levels of heavy metals in surficial sediments of the Gulf of Lions (NW Mediterranean). To correct for the grain-size effect, normalization procedures based on a clay mineral indicator element are commonly used, after a first grain size separation by sieving. In our study, we tested the applicability of this method with respect to common...

2015
Sha Yang Yun Liu

The nuclear volume effects (NVEs) of Hg, Tl and Pb isotope systems are investigated with careful evaluation on quantum relativistic effects via the Dirac's formalism of full-electron wave function. Equilibrium (202)Hg/(198)Hg, (205)Tl/(203)Tl, (207)Pb/(206)Pb and (208)Pb/(206)Pb isotope fractionations are found can be up to 3.61‰, 2.54‰, 1.48‰ and 3.72‰ at room temperature, respectively, larger...

2004
Jianping Zheng Fengxiang Lu Chunyang Wang Fangzheng Wang Huimin Li

U-Pb and Hf isotope analyses of zircons from felsic granulite xenoliths in Mesozoic volcanics reveal Early Archean ($3.6 Ga) lower crust beneath the younger (,2.85 Ga) southern margin of the North China craton, and suggest that the eastern part of the craton formed a coherent block by 3.6 Ga. Hf model ages indicate extraction of protoliths from the mantle ca. 4 Ga or earlier, followed by remelt...

Journal: :Nature communications 2014
Christian Timm Bryan Davy Karsten Haase Kaj A Hoernle Ian J Graham Cornel E J de Ronde Jon Woodhead Dan Bassett Folkmar Hauff Nick Mortimer Hannu C Seebeck Richard J Wysoczanski Fabio Caratori-Tontini John A Gamble

Large igneous province subduction is a rare process on Earth. A modern example is the subduction of the oceanic Hikurangi Plateau beneath the southern Kermadec arc, offshore New Zealand. This segment of the arc has the largest total lava volume erupted and the highest volcano density of the entire Kermadec arc. Here we show that Kermadec arc lavas south of ~32°S have elevated Pb and Sr and low ...

Journal: :Analytical and bioanalytical chemistry 2008
David De Muynck Christophe Cloquet Elisabeth Smits Frederik A de Wolff Ghylaine Quitté Luc Moens Frank Vanhaecke

Archaeological samples originating from a cemetery of a Roman settlement, Pretorium Agrippinae (1st-3rd century A.D.), excavated near Valkenburg (The Netherlands) have been subjected to Pb isotopic analysis. The set of samples analysed consisted of infant bone tissue and possible sources of bone lead, such as the surrounding soil, garum, and lead objects (e.g., water pipes). After sample digest...

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