scholarly journals In-situ Lu – Hf geochronology of calcite

2022 ◽  
Author(s):  
Alexander Simpson ◽  
Stijn Glorie ◽  
Martin Hand ◽  
Carl Spandler ◽  
Sarah Gilbert ◽  
...  

Abstract. The ability to constrain the age of calcite formation is of great utility to the Earth Science community, due to the ubiquity of calcite across a wide spectrum of geological systems. Here, we present the first in-situ laser ablation inductively coupled tandem mass spectrometry (LA-ICP-MS/MS) Lu–Hf ages for calcite, demonstrating geologically meaningful ages for IOCG and skarn mineralisation, carbonatite intrusion and low grade metamorphism. The analysed samples range in age between ca. 0.9 Ga and ca. 2 Ga with uncertainties between 1.4 % and 0.5 % obtained from calcite with Lu concentrations as low as ca. 0.5 ppm. The Lu–Hf system in calcite appears to be able to preserve primary precipitation ages over a significant amount of geological time, although further research is required to constrain the closure temperature. The in-situ approach allows calcite to be rapidly dated while maintaining its petrogenetic context with mineralization and other associated mineral processes. Therefore, LA-ICP-MS/MS Lu–Hf dating of calcite can be used to resolve the timing of complex mineral paragenetic sequences that are a feature of many ancient rock systems.

2020 ◽  
Vol 58 (3) ◽  
pp. 293-311 ◽  
Author(s):  
Zeinab Azadbakht ◽  
David R. Lentz

ABSTRACT Biotite grains from 22 felsic intrusions in New Brunswick were mapped in situ using a laser ablation-inductively coupled plasma-mass spectrometer (LA-ICP-MS). We investigated the extent to which biotite can retain its magmatic zoning patterns and, where zoning does exist, how it can be used to elucidate early to late stage, syn-magmatic to post-crystallization processes. Although the major element and halogen contents of the examined biotite phenocrysts are homogeneous, two-thirds of the grains display trace-element zoning for Ba, Rb, and Cs. The results also indicated that zoning is better retained in larger grains (i.e., > 500 × 500 μm) with minimal alteration and mineral inclusions. An exceptionally well-zoned Li-rich siderophyllite from the Pleasant Ridge topaz granite in southwestern New Brunswick shows Ti, Ta, Sn, W, Cs, Rb, and V (without Li or Ba) zoning. Cesium values increase from 200 to 1400 ppm from core to rim. Conversely, Sn and W values decrease toward the rim (50 to 10 and 100 to 10 ppm, respectively). Tantalum and Ti values show fewer variations but drop abruptly close to the rim of the grain (100 to 20 and 2000 to 500 ppm, respectively). These observations may indicate crystallization of mineral phases with high partition coefficients for these highly incompatible elements (except Ti) (e.g., cassiterite and rutile) followed by fractionation of a fluid phase at a later stage of magma crystallization. The preservation of zoning may indicate rapid cooling post-crystallization of the parent magma.


2017 ◽  
Vol 32 (5) ◽  
pp. 975-986 ◽  
Author(s):  
Lie-Wen Xie ◽  
Jin-Hui Yang ◽  
Qing-Zhu Yin ◽  
Yue-Heng Yang ◽  
Jing-Bo Liu ◽  
...  

A new LA-MIC-ICP-MS analytical technique has been developed for the rapid measurement of 206Pb/238U zircon age (<1%, 2s) at a high spatial resolution. We show that this technique can be routinely employed to date U–Pb in small and/or complex zircons, providing a powerful tool for geochronology.


2019 ◽  
Vol 34 (9) ◽  
pp. 1800-1809 ◽  
Author(s):  
Wen Zhang ◽  
Zaicong Wang ◽  
Frédéric Moynier ◽  
Edward Inglis ◽  
Shengyu Tian ◽  
...  

An in situ Zr isotopic analytical method for zircons was developed using LA-MC-ICP-MS to reveal the Zr stable isotope variation in the complex mineral crystallization history.


2019 ◽  
Vol 34 (8) ◽  
pp. 1546-1552 ◽  
Author(s):  
Lü-Yun Zhu ◽  
Yong-Sheng Liu ◽  
Shao-Yong Jiang ◽  
Jie Lin

The 187Os/188Os ratio in low-Os sulfides could be in situ measured precisely by LA-MC-ICP-MS equipping an array of ion counters.


2015 ◽  
Vol 30 (2) ◽  
pp. 515-524 ◽  
Author(s):  
Qing Chang ◽  
Jun-Ichi Kimura ◽  
Bogdan Stefanov Vaglarov

An analytical protocol using LA-MC-ICP-MS for precise Sr isotope ratio analysis from small glass samples is presented.


2017 ◽  
Vol 32 (11) ◽  
pp. 2246-2253 ◽  
Author(s):  
Gelian Gong ◽  
Saijun Sun ◽  
Jibin Zhou ◽  
Congyin Li ◽  
Xu Liang ◽  
...  

Simultaneous in situ concentration determination by LA-ICP-MS and LA-ICP-OES.


2020 ◽  
Vol 8 ◽  
Author(s):  
Han Zhao ◽  
Xin-Miao Zhao ◽  
P. J. Le Roux ◽  
Wen Zhang ◽  
Hao Wang ◽  
...  

Clinopyroxene is a major host mineral for lithophile elements in the mantle lithosphere, and therefore, its origin is vital for constraints on mantle evolution and melt generation. In situ Sr isotopic measurement of clinopyroxene has been available since the recent development of laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) in the 2000s. Therefore, there is an increasing demand for natural clinopyroxene reference materials for Sr isotope microanalysis. In this contribution, we present six natural clinopyroxene reference materials from South Africa (JJG1424) and China (YY09-47, YY09-04, YY09-24, YY12-01, and YY12-02) for Sr isotope microanalysis. The Sr content of these clinopyroxenes ranges from 50 to 340 μg g−1, which covers most natural clinopyroxene compositions. Homogeneity of these potential reference materials were investigated and evaluated in detail over a 2-year period using 193-nm nanosecond and 257-nm femtosecond laser systems coupled to either a Neptune or Neptune Plus MC-ICP-MS. Additionally, the major and trace element of these clinopyroxenes were examined by electron probe microanalyzer (EPMA) as well as solution and laser ICP-MS. The in situ87Sr/86Sr values obtained for the six natural clinopyroxene reference materials agree well with data obtained using the thermal ionization mass spectrometer (TIMS) method. The Sr isotopic stability and homogeneity of these clinopyroxenes make them potential reference materials for in situ Sr microanalysis to correct instrumental fractionation or as quality control materials for analytical sessions. The new Sr isotope data provided here might be beneficial for microbeam analysis in the geochemical community.


Sign in / Sign up

Export Citation Format

Share Document