U pb dating of zircon by la icp ms

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Due to unresolved contributions to uncertainty from the lack of a common Pb correction and from potential matrix effects between standards and unknowns, however, this estimate cannot be universally applied to all unknowns.

Nevertheless, the results of this study provide an example of the type of precision and accuracy that may be possible with this technique under ideal conditions.

The 1.7-1.5 Ga detrital zircons in the Langshan Group, which might be derived from the “Zhaertai-Bayan Obo-Huade” Mesoproterozoic rift system in the northern margin of the NCC, are not found in the Precambrian strata of the Alxa block.

The detrital zircon age peaks of the Langshan group are well correlated to the known Precambrian tectono-thermal events that affected both the Alxa block and the NCC.

In this study we used LA-ICP-MS (laser ablation–inductively coupled plasma–mass spectrometry) to determine U-Pb ages of 5 zircon samples of known age (∼1800 Ma to ∼50 Ma) in order to determine the reproducibility, precision, and accuracy of this geochronologic technique.

The relationship between the Alxa block and the North China Craton (NCC) is one of the controversial tectonic issues in China.

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Much similarity in ages of the three units has thus proved that the whole Guposhan granite complex was formed in the same period of time.The laser ablation pit sizes ranged from 30 to 40 μm in diameter.Laser-induced time-dependent fractionation is corrected by normalizing measured ratios in both standards and samples to the beginning of the analysis using the intercept method.Therefore, both U–Pb and U–Th methods result in similar ages of ~ 0.1 Ma for the Toya Tephra, in agreement with the quartz TL age (104 ± 30 to 118 ± 30 ka) of Ganzawa and Ike (2011).It was revealed that the simultaneous U–Pb and U–Th zircon dating technique using LA-ICP-MS is easy to apply and is useful for Quaternary tephras in that it can give age information on the tephra itself and xenocrystic zircons in a quick and cost-effective manner.

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