For this episode we read: "Laser-Induced Breakdown Spectroscopy – An Emerging Analytical Tool for Mineral Exploration (Harmon et al., 2019)"

Starting from the basics of what is LIBS through to cutting edge applications, Andrew Somers (Global Business Director: Geochemistry at SciAps Inc.) is here to guide us through the ins and outs of this tech. 

For our young geochemists - are you nervous about making the jump from working at a mining company to working for a vendor? Andrew has some words of wisdom on this too. 

What are we observing versus what are we supposed to see, in other words, how (and how much) is dogma directing our interpretations? We explore this concept this month when we delve into Duncan McLeish's PhD work on the transport and deposition of gold at the Brucejack Deposit (Canada). 

In a world where aqueous complexation has long been considered the only viable means of transporting gold to depositional sites in hydrothermal ore-forming systems, Duncan et al. found that rejecting dogma was of the utmost importance. For example, a major weakness of the Au transport in solution hypothesis is that it cannot readily explain the formation of ultrahigh-grade gold veins when transporting Au at ppb levels.

...so how do “bonanza” veins contain weight-percent levels of gold in some epithermal and orogenic deposits?

...what are colloids and flocculation?

...why is this research both exciting and important? 

All this and more in this episode! Put on your thinking caps, it's time to listen to some applied chemistry, economic geology and a little bit of philosophy. 

For this episode we read "Colloidal transport and flocculation are the cause of the hyperenrichment of gold in nature" by McLeish et al., 2021. 

Did you know that in addition to being one of our industry's geochemical powerhouses, JC is also an artist? But also as we continue along in the episode we'll see that he's perhaps a staunch businessman. 

For this month's episode we reviewed a PDAC short course organized by JC and Lynda Bloom entitled: "Geochemical Modeling for Orebody Knowledge and Exploration Targeting Workshop" - including his helpful Review on Methodologies for Geochemical Data Analysis. The course spans fundamentals (including QA/QC), a review of methodologies, interpretation of 4 acid ICP data, geometallurgy, ore body knowledge, regional soil geochemistry, and applications of till and indicator minerals in glaciated geochemistry. The idea is that as geochemists we need to move past just exploration and into the realms of mine, mill and reclamation. If we have geochemistry collected at any point, by any group it must be standardized as a true multi-client dataset. Sample the overburden! Have a geochemist overseeing your database and controlling how the rocks are sampled from a multiclient perspective. "Until we do this, geochemistry will never be looked at in a company as a valuable asset, but as an expense." 

As a sidenote, JC's section of the course contains topics, such as compositional data, geochemistry templates, and unsupervised and supervised learning. Buckle up geochemists and geochemistry enthusiasts... see you on the other side of this fascinating interview! 

Article: Random forest rock type classification with integration of geochemical and photographic data (Trott et al., 2022)

Do you want to integrate machine learning into your exploration workflow, but feel precluded from doing so because of complicated terminology in the majority of the literature? Have a crack at Mac's first paper and then join us for this discussion on how he implemented a relatively simple, but well-constrained, study to provide explorationists with confidence on joining the ML push towards making core logging more quantitative. 

For our young listeners, Mac has some twists and turns on his way towards his current position as a PhD student at Queen's as well as being an embedded researcher at Goldspot. 

Also... the tea is good. 

Have you perused a geochemistry lab schedule and not known where to start? Don't worry - the answers are not obvious and GeocHemiSTea is here to help! 

We have broken this episode into six sections to get to your answers quicker, but considering the complexity of the topic and the importance of having the best data possible we recommend listening to this episode in its entirety! 

For this episode we had a squiz at: "Mineral Geochemistry Vectoring: Uncovering Northwest Queensland’s Hidden Potential" (Steadman et al., 2021), "Improving geological logging of drill holes using geochemical data and data analytics for mineral exploration in the Gawler Ranges, South Australia" (Hill et al., 2021), and the tutorials on the Mineral Mapping website. 

There's a role for classical geochemistry (bivariate plots, probability plots, etc.) to play, but the future is moving towards a data science approach to geochemical data. Come listen to Mike's take on where geochemistry in industry is heading and where it still needs to shift. 

Excited for Mike's upcoming episode on bridging the gap between classical geochemistry and geochemistry in data science? Enjoy a teaser on how our email chain evolved during the development of this episode! 

For this episode we read: "A User's Guide to Basalt Discrimination Diagrams" by Pearce (1996).

Surely you have seen a geochemical diagram before... Winchester and Floyd (1977) for the classification of volcanic rocks or even Pearce's 1996 diagram to classify basalts. Have you combed the literature to find the most fit-for-purpose diagram for your own rock samples? Look no further! In this discussion with Pim van Geffen we talk about how to use the principles outlined in this book chapter to create your own diagrams. 

These questions were meant to be a summary at the end of Episode 5 to tie everything together, instead there is so much great information that we decided to give this bonus content to you as a preview of what is to come in Thursday's episode!