scholarly journals Apatite U-Pb Thermochronology: A Review

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1095
Author(s):  
David M. Chew ◽  
Richard A. Spikings
Keyword(s):  
Mass Spectrometry ◽  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Effective Diffusion ◽  
Depth Profiling ◽  
Fickian Diffusion ◽  
Low Grade ◽  
Inductively Coupled ◽  
Apatite Crystals ◽  
Icp Ms

The temperature sensitivity of the U-Pb apatite system (350–570 °C) makes it a powerful tool to study thermal histories in the deeper crust. Recent studies have exploited diffusive Pb loss from apatite crystals to generate t-T paths between ~350–570 °C, by comparing apatite U-Pb ID-TIMS (isotope dilution-thermal ionisation mass spectrometry) dates with grain size or by LA-MC-ICP-MS (laser ablation-multicollector-inductively coupled plasma-mass spectrometry) age depth profiling/traverses of apatite crystals, and assuming the effective diffusion domain is the entire crystal. The key assumptions of apatite U-Pb thermochronology are discussed including (i) that Pb has been lost by Fickian diffusion, (ii) can experimental apatite Pb diffusion parameters be extrapolated down temperature to geological settings and (iii) are apatite grain boundaries open (i.e., is Pb lost to an infinite reservoir). Particular emphasis is placed on detecting fluid-mediated remobilisation of Pb, which invalidates assumption (i). The highly diverse and rock-type specific nature of apatite trace-element chemistry is very useful in this regard—metasomatic and low-grade metamorphic apatite can be easily distinguished from sub-categories of igneous rocks and high-grade metamorphic apatite. This enables reprecipitated domains to be identified geochemically and linked with petrographic observations. Other challenges in apatite U-Pb thermochronology are also discussed. An appropriate choice of initial Pb composition is critical, while U zoning remains an issue for inverse modelling of single crystal ID-TIMS dates, and LA-ICP-MS age traverses need to be integrated with U zoning information. A recommended apatite U-Pb thermochronology protocol for LA-MC-ICP-MS age depth profiling/traverses of apatite crystals and linked to petrographic and trace element information is presented.

scholarly journals Trace Element Micro-Analytical Imaging via Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)

2011 ◽  
Vol 17 (S2) ◽  
pp. 566-567 ◽  
Author(s):  
A Netting ◽  
J Payne ◽  
B Wade ◽  
T Raimondo
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Unraveling the mechanism and impact of oxide production in LA-ICP-MS by comprehensive analysis of REE-Th-U phosphates

2017 ◽  
Vol 32 (10) ◽  
pp. 2003-2010 ◽  
Author(s):  
Keita Itano ◽  
Tsuyoshi Iizuka
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Comprehensive Analysis ◽  
Inductively Coupled ◽  
Oxide Production ◽  
Icp Ms ◽  
Isotopic Analyses ◽  
Plasma Mass Spectrometry

Oxide interference can be problematic for trace element and isotopic analyses using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).

scholarly journals Ecological, Oceanographic and Temperature Controls on the Incorporation of Trace Elements into Globigerina Bulloides and Globoconella Inflata in the Southwest Pacific Ocean

2021 ◽  
Author(s):  
◽  
Julene Marr
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Water Temperature ◽  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Inductively Coupled ◽  
Globigerina Bulloides ◽  
Carbonate Ion ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

<p>Trace element ratios (Mg/Ca, Al/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca) measured by laser ablation inductively coupled plasma mass spectrometry plus and test weight and size data are presented for two planktonic foraminiferal species, Globigerina bulloides and Globoconella inflata. These data will be used to investigate the potential of Mg/Ca ocean thermometry and other trace element proxies of past ocean chemistry using these species. Foraminifera were sampled from core-top sediments from 10 sites in the Southwest Pacific Ocean, east of New Zealand, spanning latitudes of c.33' to 54' S and temperatures of 6-19' C at 75-300 m water depth. Mg/Ca in G. bulloides correlates strongly with observed water temperatures at 200 m depth and yields a new calibration of Mg/Ca = 0.941 exp 0.0693*T (r2 = 0.95). When G. bulloides Mg/Ca data from this study are combined with previously published data for this species, a calibration of Mg/Ca = 0.998 exp 0.066*T (r2 = 0.97) is defined. Significant variability of Mg/Ca values (20-30%) was found for the four largest chambers of G. bulloides with the final chamber consistently recording the lowest Mg/Ca values. This is interpreted to reflect changes in the depth habitat towards the end of the life cycle of G. bulloides. Levels of A1 and the micronutrients Mn and Zn in G. bulloides were found to differ significantly between Subtropical and Subantarctic Water masses, suggesting these elements can potentially be used as water mass tracers. No clear relationship between Mg/Ca and temperature was observed for G.inflata. This is interpreted, in part, to reflect the ecological niche that G. inflata occupies at the base of the thermocline, coupled with the impact of heavy secondary calcite which lowers Mg/Ca values. A correlation between size normalized test weight, water temperature and seawater carbonate ion concentration is observed for G. bulloides suggesting a modern calibration that could be potentially applied for paleoceanographic reconstructions of ocean water temperature and carbonate ion concentrations. No correlation between temperature or carbonate ion was found with size normalized G. inflata test weights. However, a bimodal population of G. inflata test weights indicates a possible link between high levels of chlorophyll-a in surface waters and light G. inflata tests. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and solution-based techniques for measuring Mg/Ca in G. bulloides yield compatible results. However, this is possible only when minimal dissolution of test calcite has occurred during the reductive and dilute acid leaching stages of cleaning prior to solution analysis, or, if only the older three visible chambers are used for LA-ICP-MS analysis. LA-ICP-MS analysis is an effective method for measuring trace element/Ca values in foraminifera, especially for small sample sizes, and enables the test to be used for further geochemical analysis (e.g. boron or carbon/oxygen stable isotope analysis).</p>

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