scholarly journals Just a crush? Contamination of archaeological samples by different grinding media

2014 ◽  
Vol 2 (2) ◽  
Author(s):  
Rachel E. Ten Bruggencate ◽  
Mostafa Fayek ◽  
Brooke Milne ◽  
Robert W. Park ◽  
Douglas R. Stenton

A chert cobble from an archaeological quarry on southern Baffin Island, Canada, was divided and crushed using five different methods: i) agate mortar and pestle, ii) stainless steel shatterbox, iii) tungsten carbide shatterbox, iv) alumina ceramic shatterbox, and v) zirconia ceramic shatterbox. Powders produced by each method were submitted for acid digestion and analysis by inductively coupled plasma mass spectrometry. The trace element results indicate that different crushing media can contribute significant trace element contamination to chert during the grinding process. These results demonstrate the need for an informed approach to the selection of sample preparation methods when submitting archaeological samples for solution or pellet based geochemical analysis.

2010 ◽  
Vol 74 (4) ◽  
pp. 645-658 ◽  
Author(s):  
F. C. J. Vilalva ◽  
S. R. F. Vlach

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.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10082
Author(s):  
Jamin G. Wieringa ◽  
Juliet Nagel ◽  
David M. Nelson ◽  
Bryan C. Carstens ◽  
H. Lisle Gibbs

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.


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