Papers by Keyword: Pb Isotope

Abstract: The Mesozoic Hukeng granite body locates in southeast limb of Wugongshan compound anticline in Jiangxi Province, South China. This study uses samples from the Hukeng granite body to determine the characteristics of Sr-Nd-Pb isotopes and source of the granite body. The rocks have ⁸⁷Sr/⁸⁶Sr ratios as high as 0.84112, suggesting that crustal contamination existed there. The rocks have higher ratios of ⁸⁷Rb/⁸⁶Sr, ⁸⁷Sr/⁸⁶Sr and (⁸⁷Sr/⁸⁶Sr)_i, and lower ratios of ¹⁴⁷Sm/¹⁴⁴Nd, ⁴³Nd/¹⁴⁴Nd and lower ε_Nd(t), indicating that the Hukeng granite body possessesEMⅡ-like characteristics. Combined with Pb isotopic values (²⁰⁶Pb/²⁰⁴Pb ratios from 18.5313 to 18.8460, ²⁰⁷Pb/²⁰⁴Pb ratios from 15.6562 to 15.6782 and ²⁰⁸Pb/²⁰⁴Pb ratios from 38.7015 to 38.7565), the Hukeng granite body originated from EMⅡ and suffered crustal contamination in certain extent.

Abstract: In the Danchi mineralization belt of Guangxi province, south China, the Dachang tin-polymetallic ore deposit is one of the largest Sn ore deposits in this world. But about the genesis and the ore source, there have been some disputes. In terms of the Dafulou deposit, the mineralization model and deposit mechanism is rather illegibility. By analysing and comparing the lead isotope of three ore deposit (the Changpo, the Lamo and the Dafulou), it show that the correlations of 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb of sulfide minerals demonstrate obvious excellent linear relation. So, it is also suggested that the eastern mineralization belt, the middle mineralization belt and the western mineralization belt shared the same ore source. And, according to the features of no.22 ore body, the Dafulou deposit is characterized with the characteristics of the Sedimentary Exhalative Deposit (SEDEX).

Abstract: The atomic-scale graded structure of In-Pb alloy was formed by an ultracentrifuge under a gravitational field of 0.81 x 106 g for 100 hours at 150 °C in solid state. The isotope ratio measurements were performed on the centrifuged sample with secondary ion mass spectrometer (SIMS, CAMECA IMS-6f). 206Pb/208Pb and 207Pb/208Pb isotope ratio changed with negative gradient in the direction of centrifugal force approximately 1.5% and 0.8%, respectively. There was a tendency that the heavy 208Pb isotope abundance increased and the light 206Pb isotope abundance decreased in the direction of centrifugal force. Three-isotope diagram of 206Pb/208Pb versus 207Pb/208Pb proved that the isotope fractionation depends on the isotopic mass difference. These results showed that a strong gravitational field not only affected the inter-diffusion but also the self-diffusion in this alloy by causing isotope fractionation effect, which was dependent on the mass-difference.