scholarly journals Chlorite-White Mica Pairs’ Composition as a Micro-Chemical Guide to Fingerprint Massive Sulfide Deposits of the Bathurst Mining Camp, Canada

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 125 ◽  
Author(s):  
Azam Soltani Dehnavi ◽  
Christopher McFarlane ◽  
David Lentz ◽  
Sean McClenaghan ◽  
James Walker

The compositions of phyllosilicates, with a focus on fluid-mobile elements, were evaluated as a means to fingerprint the Middle Ordovician metamorphosed (greenschist facies) volcanogenic massive sulfide deposits of the Bathurst Mining Camp (BMC), Canada. Ninety-five drill-core samples from six of the major deposits of the Bathurst Mining Camp (Brunswick No. 12, Heath Steele B zone, Halfmile Lake Deep zone, Key Anacon East zone, Louvicourt, and Restigouche) were analyzed using electron microprobe and laser ablation inductively coupled plasma-mass spectrometry. Typically, phyllosilicates (chlorite, white mica, and to a lesser extent biotite) are ubiquitous phases in the host rocks of the massive sulfide deposits of the BMC. Electron microprobe analysis results show a wide compositional variation in chlorite and white mica. Laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis was performed to measure fluid-mobile elements, showing that Tl is distinctly enriched in all white mica (up to 719 ppm) relative to chlorite (up to 50.1 ppm). Chlorite hosts Sn (up to 4600 ppm), Hg (up to 7.3 ppm), Sb (up to 35.4 ppm), As (up to 1320 ppm), In (up to 307 ppm), Cd (up to 83.2 ppm), and Se (up to 606 ppm). White mica hosts Sn (up to 1316 ppm), Hg (up to 93 ppm), Sb (up to 1630 ppm), As (up to 14,800 ppm), In (up to 1186 ppm), Cd (up to 98 ppm), and Se (up to 38.8 ppm). Limited LA-ICP-MS analysis on biotite indicates a higher overall concentration of Tl (mean = 14.6 ppm) relative to co-existing white mica (mean = 2.18 ppm). On average, biotite is also more enriched in Hg, Sn, and Ba relative to chlorite and white mica. Laser Ablation ICP-MS profiles of chlorite, white mica, and biotite demonstrate smooth time-dependent variations diagnostic of structural substitution of these elements. Compositional variation of chlorite-white mica pairs presented in the current study shows systematic variations as a function of distance from the mineralized horizons. This highlights the potential to use trace-element signatures in these phyllosilicate pairs to identify proximal (chlorite) and distal (white mica) footprints for volcanogenic massive sulfides exploration.

2021 ◽  
pp. geochem2020-043
Author(s):  
Madison A. Schmidt ◽  
Matthew I. Leybourne ◽  
Jan M. Peter ◽  
Duane C. Petts ◽  
Simon E. Jackson ◽  
...  

There is increasing acceptance of the presence of variable magmatic contributions to the mineralizing fluids in the formation of volcanogenic massive sulfide (VMS) deposits. The world-class Windy Craggy Cu-Co-Au deposit (>300 MT @ 2.12 wt.% Cu) in northwestern British Columbia is of interest because, unlike most VMS deposits, quarts fluid inclusions from within the deposit range from relatively low to intermediate salinity (most 6-16 wt.% equivalent). In this study we used an excimer (193 nm) laser ablation system interfaced to a quadrupole inductively coupled plasma mass spectrometer to quantify key metals and metalloids that are considered by many to be indicative of magmatic contributions to hydrothermal ore deposits. Although LA-ICP-MS signals from these low-salinity inclusions are highly transient, we were able to quantify Na, Mg, K, Ca, Mn, Fe, Co, Cu, Zn, Sr, Sn, Ba, Ce, Pb and Bi consistently – of the 34 elements that were monitored. Furthermore, Cl, Sb, Cd, Mo, Rb, Br, and As were also measured in a significant number of inclusions. Comparison of the fluid inclusion chemistry with unaltered and altered mafic volcanic and sedimentary rocks and mineralized samples from the deposit indicate that enrichment in the main ore metals (Cu, Zn, Fe, Pb) in the inclusions reflects that of the altered rocks and sulfides. Metals and metalloids that may indicate a magmatic contribution typically show much greater enrichments in the fluid inclusions much greater over the host rocks at the same Cu concentration; in particular Bi, Sn and Sb are significantly elevated when compared to the host rock samples. These data are consistent with the ore-forming fluids at Windy Craggy having a strong magmatic contribution.


2016 ◽  
Vol 31 (4) ◽  
pp. 1030-1033 ◽  
Author(s):  
J. S. Hamilton ◽  
E. L. Gorishek ◽  
P. M. Mach ◽  
D. Sturtevant ◽  
M. L. Ladage ◽  
...  

A new single Peltier element ablation cell is described and its applicability to biological sampling discussed to evaluate its performance.


2017 ◽  
Vol 32 (8) ◽  
pp. 1500-1507 ◽  
Author(s):  
Jorge Moreda-Piñeiro ◽  
Alicia Cantarero-Roldán ◽  
Antonio Moreda-Piñeiro ◽  
José Ángel Cocho ◽  
Pilar Bermejo-Barrera

An approach by laser ablation (LA) coupled with inductively coupled mass spectrometry (ICP-MS) for multi-element determination in whole blood is described.


2004 ◽  
Vol 57 (10) ◽  
pp. 921 ◽  
Author(s):  
Sebastien Rauch ◽  
Gregory M. Morrison

Recent developments in laser microprobes and the coupling of laser ablation (LA) to inductively coupled plasma mass spectrometry (ICP-MS) has opened up the possibility for detailed analysis of individual sediment grains and the elucidation of metal association with bulk elements and phases. Here, LA–ICP-MS is used for the micrometer-resolved, multi-element analysis of Pb and bulk elements such as Fe, Mg, Al, and Si. Normalized Pb signals show a clear association to Fe coatings at the surface of the particles.


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