Abstract Details
(2020) Colloidal Gold Adsorption on Phyllosilicates and the Correlation of Gold and δ7Li: Insights from Kirkland Lake, Hemlo, Hardrock and Red Lake World-Class Gold Deposits, Canada
Nadeau O
https://doi.org/10.46427/gold2020.1879
The author has not provided any additional details.
08q: Room 3, Thursday 25th June 05:30 - 05:33
Olivier Nadeau
Listed below are questions that have been submitted by the community that the author will try and cover in their presentation. To submit a question, ensure you are signed in to the website. Authors or session conveners approve questions before they are displayed here.
Submitted by Green David on Tuesday 23rd June 11:45
On a more technical note ... I really enjoyed your presentation – a nice piece of research showing a direct correlation of Au with 6Li associated with hydrothermal alteration. I feel that the inferred correlation with white micas and clays and anti-correlation with quartz and feldspars is less well demonstrated. The LA-ICP-MS maps of Red Lake are a great step to proving up the inference, but in my view needs more quantification … the maps primarily show that chlorite contains far more Li than white mica. How do you propose to prove which minerals are associated with both increased Au and 6Li or indeed if Au is actually primarily associated with small amounts of other (sulphide?) minerals?
Hi David. Of course, an 8-min presy is not a lot to well demonstrate the control of d7Li by micas/clays and/or feldspars/quartz. However, the preference of 7Li for micas/clays, and of 6Li for quartz over fluid (to a lesser degree) during fluid-rock interaction is well documented (e.g., Penniston-Dorland et al., 2017, and references therein). The laser ablation ICP-MS map of alteration at Red Lake clearly shows gold associated with white mica (sericite), not with sulfides! However at Hardrock gold, indirect methods had suggested that small amounts of gold was associated with chlorite. As you say, more work is required to ellucidate these differences. Nevertheless, the visual observation of chlorite altering to sericite may give an element of answer. What if gold was first remobilized into chlorite, and then chlorite was altered to sericite? In any case, these low amounts of gold in micas/clays become significant only for rocks which do not have large amounts of gold in sulfides, tellurides, and native gold/electrum... This has all the makings for an excellent geochemical exploration tracer...
On a more technical note ... I really enjoyed your presentation – a nice piece of research showing a direct correlation of Au with 6Li associated with hydrothermal alteration. I feel that the inferred correlation with white micas and clays and anti-correlation with quartz and feldspars is less well demonstrated. The LA-ICP-MS maps of Red Lake are a great step to proving up the inference, but in my view needs more quantification … the maps primarily show that chlorite contains far more Li than white mica. How do you propose to prove which minerals are associated with both increased Au and 6Li or indeed if Au is actually primarily associated with small amounts of other (sulphide?) minerals?
Hi David. Of course, an 8-min presy is not a lot to well demonstrate the control of d7Li by micas/clays and/or feldspars/quartz. However, the preference of 7Li for micas/clays, and of 6Li for quartz over fluid (to a lesser degree) during fluid-rock interaction is well documented (e.g., Penniston-Dorland et al., 2017, and references therein). The laser ablation ICP-MS map of alteration at Red Lake clearly shows gold associated with white mica (sericite), not with sulfides! However at Hardrock gold, indirect methods had suggested that small amounts of gold was associated with chlorite. As you say, more work is required to ellucidate these differences. Nevertheless, the visual observation of chlorite altering to sericite may give an element of answer. What if gold was first remobilized into chlorite, and then chlorite was altered to sericite? In any case, these low amounts of gold in micas/clays become significant only for rocks which do not have large amounts of gold in sulfides, tellurides, and native gold/electrum... This has all the makings for an excellent geochemical exploration tracer...
Sign in to ask a question.