Allanite micro-geochronology: A LA-ICP-MS and SHRIMP U–Th–Pb study

Gregory, Courtney J.; Rubatto, Daniela; Allen, Charlotte M.; Williams, Ian S.; Hermann, Jörg; Ireland, Trevor

doi:10.1016/j.chemgeo.2007.07.029

Cited by 133 publications

(125 citation statements)

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“…Therefore, attention should be paid in correcting Pb isotopic data, and the choice of initial Pb isotopic composition would significantly influence the calculated ages [4]. We adopted the 207 Pb correction method, which has been widely used to determine the age of relatively young allanite [4,70].…”

Section: Samples and Analytical Methodsmentioning

confidence: 99%

“…Previous studies [4,14,16,73] show that precise allanite U-Th-Pb dating is influenced by several factors: (1) high and variable common Pb content; (2) excess 206 Pb from 230 Th decay in high-Th samples; and (3) lack of suitable matrix-matched allanite standards due to the large compositional variations caused by the solid solution with epidote.…”

Section: Reliability Of Allanite U-th-pb Datingmentioning

confidence: 99%

“…The Beiya and the Machangqing deposits were products of this Himalayan collisional tectonic event. 4 ) member are exposed in the ore field. O 1 x 3 comprises grayish-green fine-grained sandstone with dark-gray shale in the upper part, and white fine-grained quartz sandstone with minor shale in the lower part.…”

Section: Introductionmentioning

confidence: 99%

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LA-ICP-MS U-Th-Pb Dating and Trace Element Geochemistry of Allanite: Implications on the Different Skarn Metallogenesis between the Giant Beiya Au and Machangqing Cu-Mo-(Au) Deposits in Yunnan, SW China

Sun

et al. 2017

Minerals

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Abstract:The giant Beiya Au skarn deposit and Machangqing porphyry Cu-Mo-(Au) deposit are located in the middle part of the Jinshajiang-Ailaoshan alkaline porphyry metallogenic belt. The Beiya deposit is the largest Au skarn deposit in China, whilst the Machangqing deposit comprises a well-developed porphyry-skarn-epithermal Cu-Mo-(Au) mineral system. In this paper, we present new allanite U-Th-Pb ages and trace element geochemical data from the two deposits and discuss their respective skarn metallogenesis. Based on the mineral assemblage, texture and Th/U ratio, the allanite from the Beiya and Machangqing deposits are likely hydrothermal rather than magmatic. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) allanite U-Th-Pb dating has yielded Th-Pb isochron ages of 33.4 ± 4.6 Ma (MSWD = 0.22) (Beiya) and 35.4 ± 9.8 Ma (MSWD = 0.26) (Machangqing), representing the retrograde alteration and magnetite skarn mineralization age of the two deposits. The Beiya and Machangqing alkali porphyry-related mineralization are synchronous and genetically linked to the magmatic hydrothermal activities of the Himalayan orogenic event. Major and trace element compositions reveal that the Beiya allanite has higher Fe 3+ /(Fe 3+ + Fe 2+ ) ratios, U content and Th content than the Machangqing allanite, which indicate a higher oxygen fugacity and F content for the ore-forming fluids at Beiya. Such differences in the ore-forming fluids may have contributed to the different metallogenic scales and metal types in the Beiya and Machangqing deposit.

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Section: Samples and Analytical Methodsmentioning

confidence: 99%

Section: Reliability Of Allanite U-th-pb Datingmentioning

confidence: 99%

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LA-ICP-MS U-Th-Pb Dating and Trace Element Geochemistry of Allanite: Implications on the Different Skarn Metallogenesis between the Giant Beiya Au and Machangqing Cu-Mo-(Au) Deposits in Yunnan, SW China

Sun

et al. 2017

Minerals

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“…Firstly, the covariation is not exact, and after calibration there remains a residual error that is rarely better than 0.5 %. Secondly, it requires corrections for bulk composition for zircons with more than 2000 ppm U (Williams and Hergt, 2000;White and Ireland, 2012), or for minerals that exhibit complex solid solution, such as monazite (Gregory et al, 2007;Fletcher et al, 2010). Thirdly, some simple oxides, such as baddeleyite and rutile, exhibit orientation-related deviations from the calibration (Wingate and Compston, 2000;Schmitt et al, 2010;Taylor et al, 2012).…”

Section: W Magee Jr Et Al: Isotopologue Disequilibrium In Simsmentioning

confidence: 99%

Extreme isotopologue disequilibrium in molecular SIMS species during SHRIMP geochronology

Magee

Danišík

Mernagh

2017

Geosci. Instrum. Method. Data Syst.

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Abstract. The current limitation in the accuracy and precision of inter-element analysis in secondary ion mass spectrometry (SIMS) is the ability to find measurable quantities that allow relative differences in ionization and transmission efficiency of secondary ions to be normalized. In uraniumthorium-lead geochronology, the ability to make these corrections, or "calibrate" the data, results in an accuracy limit of approximately 1 %. This study looks at the ionization of uranium and thorium oxide species, which are traditionally used in U-Pb calibration, to explore the conditions under which isotopologues, or molecular species whose composition differs only in the isotopic composition of one or more atoms in the molecule, remain in or deviate from equilibrium.Isotopologue deficits of up to 0.2 (200 ‰) below ideal mixing are observed in UO + 2 species during SIMS gechronological analyses using the SHRIMP IIe SIMS instrument. These are identified by bombarding natural U-bearing minerals with an 18 O − 2 primary beam. The large anomalies are associated with repeat analyses down a single SIMS sputtering crater (Compston et al., 1984), analysis of high-uranium, radiation-damaged zircon, and analysis of baddeleyite. Analysis of zircon under routine conditions yield UO + 2 isotopologue anomalies generally within a few percent of equilibrium. The conditions under which the isotopologue anomalies are observed are also conditions in which the UO x -based corrections, or calibration, for relative U vs. Pb ionization efficiencies fail. The existence of these isotopologue anomalies suggest that failure of the various UO x species to equilibrate with each other is the reason that none of them will successfully correct the U / Pb ratio. No simple isotopologuebased correction is apparent. However, isotopologue disequilibrium appears to be a more sensitive tool for detecting high-U calibration breakdowns than Raman spectroscopy, which showed sharper peaks for ∼ 37 Ma high-uranium zircons than for reference zircons OG1 and Temora. U-ThSm / He ages were determined for aliquots of reference zircons OG1 (755±71 Ma) and Temora (323±43 Ma), suggesting that the broader Raman lines for the Temora reference zircons may be due to something other than accumulated radiation damage.Isotopologue abundances for UO + and ThO + and their energy spectra are consistent with most or all molecular species being the product of atomic recombination when the primary beam impact energy is greater than 5.7 keV. This, in addition to the large UO + 2 instrumentally generated isotopologue disequilibria, suggests that any attempts to use SIMS to detect naturally occurring isotopologue deviations could be tricky.

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“…The main field of application for LA-ICP-MS is in geological research, including geochronology, isotope variation in nature, and geochemistry [13][14][15][16][17]. LA-ICP-MS is established as a powerful and sensitive analytical technique in material and environmental research, in particular, for the investigation of highpurity materials, superhard materials of layered systems, or for monitoring of long-lived radionuclides in contaminated soil samples [18,19].…”

mentioning

confidence: 99%

Metal imaging on surface of micro- and nanoelectronic devices by laser ablation inductively coupled plasma mass spectrometry and possibility to measure at nanometer range

Zoriy¹,

Mayer

Becker³

2009

J. Am. Soc. Mass Spectrom.

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An analytical mass spectrometric method for the elemental analysis of nano-bioelectronic devices involved in bioengineering research was developed and applied for measurements of selected metals (Au, Ti, Pt, Cr, etc.) on interdigitated electrode array chips (IDA-chip). An imaging laser ablation inductively coupled plasma mass spectrometric (LA-ICP-MS) procedure was used to map the elements of interest on the surface of the analyzed sample. The obtained images of metals were in a good agreement and corresponded to the micro-and nanofabricated metal electrode pattern. For the analysis at nanometer resolution scale a NF-LA-ICP-MS (NF-near-field) procedure was applied, which utilize thin Ag needle to enhance laser beam energy and improve spatial resolution of the method. The results show a ϳ100ϫ enhancement of analyte signal, when the needle was positioned in the "near-field region" to the sample surface and the laser shot was performed. In addition, mass spectrometric studies of reproducibly for five separated NF-LA shots in different places of analyzed sample yielded an RSD of the measurement of 16%. io engineering (or biological engineering), including biomedical engineering and nanobiotechnology, is a new, challenging, and rapidly growing high-tech research field [1,2]. The use of biomolecules as the building blocks of higher-level functional devices will lead to applications that range from the integration of biomaterials with electronics in recognition or sensing devices [3]. Bioelectronics research also exploits to use biomolecules to perform the electronic functions that semiconductor devices currently perform, thereby offering the potential to increase integration in combination with additional functionality at the nanometer level. However, the integration of biomolecules or even whole cells with inorganic devices brings several challenges about as there are, for instance, operation of the electronic components under physiological conditions, electrically, biochemically as well as size-adapted bioinorganic interfaces, and biocompatibility of the electronic devices. The implementation of these challenges and the realization of functional bioelectronic junctions require interdisciplinary research, including microengineering, biotechnology, surface chemistry, and analytical research.The fabrication of bioelectronic component on the basis of silicon microtechnology facilitates high integration densities, high spatial resolution, combining signal recording and transducing in one device at relatively low production costs. To build and assemble bioinorganic electronic components with well defined and optimized features, it usually requires control over impurities of trace levels contaminations, which can influence the physical, electrical, magnetic, and chemical properties of thin layered systems. In particular, the biocompatibility of device can be strongly affected by organic and inorganic impurities introduced during the fabrication processes. Therefore, powerful and sensitive trace analytical techniques are ne...

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Allanite micro-geochronology: A LA-ICP-MS and SHRIMP U–Th–Pb study

Cited by 133 publications

References 50 publications

LA-ICP-MS U-Th-Pb Dating and Trace Element Geochemistry of Allanite: Implications on the Different Skarn Metallogenesis between the Giant Beiya Au and Machangqing Cu-Mo-(Au) Deposits in Yunnan, SW China

LA-ICP-MS U-Th-Pb Dating and Trace Element Geochemistry of Allanite: Implications on the Different Skarn Metallogenesis between the Giant Beiya Au and Machangqing Cu-Mo-(Au) Deposits in Yunnan, SW China

Extreme isotopologue disequilibrium in molecular SIMS species during SHRIMP geochronology

Metal imaging on surface of micro- and nanoelectronic devices by laser ablation inductively coupled plasma mass spectrometry and possibility to measure at nanometer range

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