Decoding 3-D monazite textures using LA-ICP-MS raster mapping

2020 ◽  
Author(s):  
Owen Weller ◽  
Simon Jackson ◽  
William Miller ◽  
Marc St-Onge ◽  
Nicole Rayner
Keyword(s):  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Granulite Facies ◽  
High Grade ◽  
Study Region ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
High Grade Metamorphism ◽  
Metamorphic Terranes ◽  
Melt Crystallisation

<p>Texturally complex monazite grains within two granulite-facies pelitic migmatites from southern Baffin Island, Arctic Canada, were mapped by laser ablation-inductively coupled plasma-mass spectrometry to quantitatively determine the spatial variation in trace element chemistry with a 4-5 μm resolution (with up to 1883 analyses per grain). The maps demarcate growth zones, some of which were cryptic with conventional imaging, highlighting the 3-D complexity of monazite grains that have experienced multiple episodes of growth and resorption during high-grade metamorphism. Associated monazite trace element systematics are highly variable, both within domains interpreted to have grown in a single event, and between samples that experienced similar metamorphic conditions and mineral assemblages. This result cautions against generalised petrological interpretations being made about monazite trace element signatures as it suggests sample-specific controls. Nevertheless, by quantifying monazite textures, a related U-Pb dataset is re-interpreted, allowing ages to be extracted from a continuum of concordant data. The results reveal a ~45 Myr interval between prograde metamorphism and retrograde melt crystallisation in the study region, emphasising the long-lived nature of heat flow in high-grade metamorphic terranes. Careful characterisation of monazite grains suggests that continuum-style U-Pb datasets can be decoded to provide insights into the rates of metamorphic processes.</p>

Major- and trace-element composition of REE-rich turkestanite from peralkaline granites of the Morro Redondo Complex, Graciosa Province, south Brazil

2010 ◽  
Vol 74 (4) ◽  
pp. 645-658 ◽  
Author(s):  
F. C. J. Vilalva ◽  
S. R. F. Vlach
Keyword(s):  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Alkali Feldspar ◽  
Trace Element Composition ◽  
Inductively Coupled ◽  
Coupled Substitution ◽  
Plasma Mass Spectrometry ◽  
Compositional Variations ◽  
End Members ◽  
South Brazil

AbstractTurkestanite, a rare Th- and REE-bearing cyclosilicate in the ekanite–steacyite group was found in evolved peralkaline granitesfrom the Morro Redondo Complex, south Brazil. It occurswith quartz, alkali feldspar and an unnamed Y-bearing silicate. Electron microprobe analysis indicates relatively homogeneous compositions with maximum ThO2, Na2O and K2O contentsof 22.4%, 2.93% and 3.15 wt.%, respectively, and significant REE2O3 abundances(5.21 to 11.04 wt.%). The REE patterns show enrichment of LREE over HREE, a strong negative Eu anomaly and positive Ce anomaly, the latter in the most transformed crystals. Laser ablation inductively coupled plasma mass spectrometry trace element patterns display considerable depletions in Nb, Zr, Hf, Ti and Li relative to whole-rock sample compositions. Observed compositional variations suggest the influence of coupled substitution mechanisms involving steacyite, a Na-dominant analogue of turkestanite, iraqite, a REE-bearing end-member in the ekanite–steacyite group, ekanite and some theoretical end-members. Turkestanite crystals were interpreted as having precipitated during post-magmatic stages in the presence of residual HFSE-rich fluidscarrying Ca, the circulation of which wasenhanced by deformational events.

scholarly journals Using trace elements to identify the geographic origin of migratory bats

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10082
Author(s):  
Jamin G. Wieringa ◽  
Juliet Nagel ◽  
David M. Nelson ◽  
Bryan C. Carstens ◽  
H. Lisle Gibbs
Keyword(s):  
Trace Elements ◽  
Wind Energy ◽  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Geographic Origin ◽  
Lasiurus Borealis ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Trace Element Profiles ◽  
Geographic Sources

The expansion of the wind energy industry has had benefits in terms of increased renewable energy production but has also led to increased mortality of migratory bats due to interactions with wind turbines. A key question that could guide bat-related management activities is identifying the geographic origin of bats killed at wind-energy facilities. Generating this information requires developing new methods for identifying the geographic sources of individual bats. Here we explore the viability of assigning geographic origin using trace element analyses of fur to infer the summer molting location of eastern red bats (Lasiurus borealis). Our approach is based on the idea that the concentration of trace elements in bat fur is related through the food chain to the amount of trace elements present in the soil, which varies across large geographic scales. Specifically, we used inductively coupled plasma–mass spectrometry to determine the concentration of fourteen trace elements in fur of 126 known-origin eastern red bats to generate a basemap for assignment throughout the range of this species in eastern North America. We then compared this map to publicly available soil trace element concentrations for the U.S. and Canada, used a probabilistic framework to generate likelihood-of-origin maps for each bat, and assessed how well trace element profiles predicted the origins of these individuals. Overall, our results suggest that trace elements allow successful assignment of individual bats 80% of the time while reducing probable locations in half. Our study supports the use of trace elements to identify the geographic origin of eastern red and perhaps other migratory bats, particularly when combined with data from other biomarkers such as genetic and stable isotope data.

A Palaeoarchean–Mesoarchean micro-continent entrained in the Jiao-Liao-Ji Belt at the southeastern North China Craton: evidence from the zircon record in the Bengbu area

2019 ◽  
Vol 156 (9) ◽  
pp. 1565-1586 ◽  
Author(s):  
Chaohui Liu ◽  
Guochun Zhao ◽  
Fulai Liu ◽  
Jia Cai
Keyword(s):  
Trace Element ◽  
North China Craton ◽  
Inductively Coupled Plasma ◽  
North China ◽  
Detrital Zircons ◽  
Magmatic Zircon ◽  
Inductively Coupled ◽  
Multi Stage ◽  
Plasma Mass Spectrometry ◽  
Trace Element Contents

AbstractThe Bengbu area in the southeastern North China Craton (NCC) consists predominantly of Archean–Palaeoproterozoic (gneissic) granitoids with minor supracrustal rocks (the Fengyang and Wuhe groups). This study presents new zircon laser ablation – inductively coupled plasma – mass spectrometry U–Pb and Lu–Hf isotopic data and trace-element contents for these granitoids, which improve understanding the Archean–Palaeoproterozoic crustal evolution of the NCC. Magmatic zircon U–Pb data reveal that zircons in the (gneissic) granitoids were generated by multi-stage events at 2.93, 2.73, 2.53–2.52 and 2.18–2.13 Ga. Metamorphic zircon U–Pb data obtained from these rocks show two distinct metamorphic ages of 2.49–2.52 and 1.84 Ga, suggesting that the Bengbu area experienced a regional metamorphic event at the end of the Neoarchean Era and encountered reworking by a tectonothermal event associated with the formation of the Palaeoproterozoic Jiao-Liao-Ji Belt. Trace-element compositions of magmatic zircons reveal the highest Ti concentrations (8.08±3.38 ppm) and growth temperatures (718±44 °C) for the zircons aged 2.13–2.17 Ga and an increase in zircon U/Yb ratios from 2.93 Ga (0.34±0.12) through 2.73 Ga (0.96±0.42) to 2.53 Ga (1.05±0.46), but an evident decrease at 2.17–2.13 Ga (0.61±0.40 ppm). Similar Palaeoarchean xenocrystic and detrital zircons with negativeɛHf(t) values, late Mesoarchean magmatic zircons with juvenile Hf isotopic features, early Neoarchean magmatic zircons with model ages of 2.9–3.0 Ga, and two regional metamorphic events at 2.52–2.48 and 1.88–1.80 Ga in the Bengbu and Jiaobei areas indicate a Palaeoarchean–Mesoarchean micro-continent entrained in the Jiao-Liao-Ji Belt at the southeastern NCC.

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