U-Pb zircon in situ dating with LA-MC-ICP-MS using a mixed detector configuration

The LA-MC-ICP-MS method applied to U-Pb in situ dating is still rapidly evolving due to improvements in both lasers and ICP-MS. To test the validity and reproducibility of the method, 5 different zircon samples, including the standard Temora-2, ranging in age between 2.2 Ga and 246 Ma, were dated using both LA-MC-ICP-MS and SHRIMP. The selected zircons were dated by SHRIMP and, after gentle polishing, the laser spot was driven to the same site or on the same zircon phase with a 213 nm laser microprobe coupled to a multi-collector mixed system. The data were collected with a routine spot size of 25 μm and, in some cases, of 15 and 40 μm. A careful cross-calibration using a diluted U-Th-Pb solution to calculate the Faraday reading to counting rate conversion factors and the highly suitable GJ-1 standard zircon for external calibrations were of paramount importance for obtaining reliable results. All age results were concordant within the experimental errors. The assigned age errors using the LA-MC-ICP-MS technique were, in most cases, higher than those obtained by SHRIMP, but if we are not faced with a high resolution stratigraphy, the laser technique has certain advantages.

Download Full-text

Accurate analysis of Fe isotopes in Fe- dominated minerals by excimer laser ablation MC-ICP-MS on wet plasma conditions

Atomic Spectroscopy ◽

10.46770/as.2021.703 ◽

2021 ◽

Vol 42 (5) ◽

Author(s):

Honglin Yuan

Keyword(s):

Water Vapor ◽

Laser Ablation ◽

Matrix Effect ◽

Laser Fluence ◽

Pulse Repetition Rate ◽

Isotopic Analysis ◽

Spot Size ◽

Nitrogen Gas ◽

Icp Ms

The Fe isotope ratios can be a useful tracer of geochemistry, biogeochemistry, and the environmental redox state. In this study, we investigated the feasibility of Fe isotopic analysis in Fe-dominated minerals by 193 nm excimer ns laser ablation combined with Nu Plasma 1700 high resolution MC-ICP-MS without matrix-match calibration. Several important instrument parameters were investigated, such as the effect of the addition of nitrogen gas and water vapor, the effects of analytical parameters such as ablation mode, laser fluence, pulse repetition rate, spot size on Fe isotopic mass bias during analysis were investigated as well. The results showed that the effects of ablation mode, spot size, laser pulse repetition rate, and line scan speed can be neglected, while laser fluence and matrix effects had significant influence on the Fe isotopic mass bias at dry plasma condition. These problems can be minimized using consistent lower fluence (1.5‒3.5 J·cm-2), as well as the wet plasma conditions can significantly reduce the matrix effect in Fe isotopic analysis. Fortunately, with the water vapor and nitrogen gas addition after the ablation cell, an accurate and precise Fe isotope in pyrite, manganite, hematite, and chalcopyrite analysis by ns-LA-MC-ICP-MS can be achieved with non-matrix-matched calibration. The obtained accuracy and reproducibility of the in situ determinations of δ56FeIRMM-014 were both better than ± 0.10‰ (2 SD). This study indicated that there was a serious matrix effect in the Fe isotopic analysis of Fe-dominated minerals by ns- LA-MC-ICP-MS, and nitrogen gas mixed with water vapor-assisted ns- LA-MC-ICP-MS were an appealing option for the in situ Fe isotope analysis of Fe-dominated minerals with non-matrix-matched calibration.

Download Full-text

Simultaneous in-situ determination of U-Pb age and trace elements in zircon by LA-ICP-MS in 20 μm spot size

Chinese Science Bulletin ◽

10.1007/s11434-007-0160-x ◽

2007 ◽

Vol 52 (9) ◽

pp. 1257-1264 ◽

Cited By ~ 158

Author(s):

XiaoMing Liu ◽

Shan Gao ◽

ChunRong Diwu ◽

HongLin Yuan ◽

ZhaoChu Hu

Keyword(s):

Trace Elements ◽

Spot Size ◽

Icp Ms

Download Full-text

In situ Fe isotopic analyses of fourteen reference materials using a synthetic Cr standard for mass bias and isobaric interference corrections by femtosecond LA-MC-ICP-MS

Journal of Analytical Atomic Spectrometry ◽

10.1039/d0ja00465k ◽

2021 ◽

Author(s):

Lei Xu ◽

Wen Zhang ◽

Tao Luo ◽

Jin-Hui Yang ◽

Zhaochu Hu

Keyword(s):

Reference Materials ◽

Isotope Ratios ◽

Isobaric Interference ◽

Analytical Technique ◽

Mass Bias ◽

Icp Ms ◽

Isotopic Analyses

High precise and accurate measurements of Fe isotope ratios for fourteen reference materials from the USGS, MPI-DING and CGSG were successfully carried out using a developed analytical technique by fs...

Download Full-text

Hydrothermal origin of the Naojiao Fe deposit in Lingxiang district, Eastern China: Evidence from in-situ LA-ICP-MS magnetite trace element analysis

Solid Earth Sciences ◽

10.1016/j.sesci.2021.06.004 ◽

2021 ◽

Author(s):

Haibo Yan ◽

Jing Tian ◽

Deshui Yu ◽

Jian Di ◽

Jiahao Li ◽

...

Keyword(s):

Trace Element ◽

Eastern China ◽

Trace Element Analysis ◽

Element Analysis ◽

Hydrothermal Origin ◽

Icp Ms

Download Full-text

In-situ determination of antimony isotope ratios in Sb minerals by femtosecond LA-MC-ICP-MS

Journal of Analytical Atomic Spectrometry ◽

10.1039/d1ja00089f ◽

2021 ◽

Author(s):

Andreas Benjamin Kaufmann ◽

Marina Lazarov ◽

Stefan Kiefer ◽

Juraj Majzlan ◽

Stefan Weyer

Keyword(s):

Laser Ablation ◽

Femtosecond Laser ◽

Femtosecond Laser Ablation ◽

Isotope Ratios ◽

Icp Ms

Here we present a method for in-situ determination of stable antimony (Sb) isotope compositions by ultraviolet (UV)-femtosecond-laser-ablation-multi-collector-ICP-MS (fs-LA-MC-ICP-MS). Metallic antimony and a number of Sb minerals (stibnite, senarmontite, chalcostibite, tetrahedrite,...

Download Full-text

Accurate dating of stalagmites from low seasonal contrast tropical Pacific climate using Sr 2D maps, fabrics and annual hydrological cycles

Scientific Reports ◽

10.1038/s41598-021-81941-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mohammadali Faraji ◽

Andrea Borsato ◽

Silvia Frisia ◽

John C. Hellstrom ◽

Andrew Lorrey ◽

...

Keyword(s):

Principal Component ◽

Tropical Pacific ◽

In Situ Monitoring ◽

Marine Aerosols ◽

Icp Ms ◽

Optical Maps ◽

Hydrological Cycles ◽

Climate Proxies ◽

Dimensional Mapping

AbstractTropical Pacific stalagmites are commonly affected by dating uncertainties because of their low U concentration and/or elevated initial 230Th content. This poses problems in establishing reliable trends and periodicities for droughts and pluvial episodes in a region vulnerable to climate change. Here we constrain the chronology of a Cook Islands stalagmite using synchrotron µXRF two-dimensional mapping of Sr concentrations coupled with growth laminae optical imaging constrained by in situ monitoring. Unidimensional LA-ICP-MS-generated Mg, Sr, Ba and Na variability series were anchored to the 2D Sr and optical maps. The annual hydrological significance of Mg, Sr, Ba and Na was tested by principal component analysis, which revealed that Mg and Na are related to dry-season, wind-transported marine aerosols, similar to the host-rock derived Sr and Ba signatures. Trace element annual banding was then used to generate a calendar-year master chronology with a dating uncertainty maximum of ± 15 years over 336 years. Our approach demonstrates that accurate chronologies and coupled hydroclimate proxies can be obtained from speleothems formed in tropical settings where low seasonality and problematic U–Th dating would discourage the use of high-resolution climate proxies datasets.

Download Full-text