Geochemical exploration in low sulfidation epithermal systems with Simon Griffiths

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1. 

   S5 · E2 · 18 Feb 2026 · 1 hr 16 min

   Fit-for-Purpose Geochemistry and Fewer Bad Programs with Simon Bolster

   Simon Bolster joins GeOCHemISTea to unpack what actually makes near-surface geochemistry work in mineral exploration: understanding regolith and landforms before you ever “put dirt in bags.” With four decades in gold exploration, Simon argues that many programs fail not because geochemistry is “bad,” but because sampling and analytical choices do not match the terrain,the cover, or the project stage. The conversation moves from regolith terrain assessment andmapping as the real starting point, to why “lowest detection limit” is not a substitute for good planning. Simon also breaks down…

2. 

   S5 · E1 · 21 Jan 2026 · 1 hr 7 min

   From Geomet to the Mill: Breaking Down Silos with Mohsen Yahyaei

   In this episode of GeOCHemISTea, host Sam Scher engages in a thought-provoking conversation with Professor Mohsen Yahyaei, a mineral processing engineer and director at the Julius Kruttschnitt Mineral Research Center. They explore the impact of geographical differences on mental health, particularly how varying daylight hours can affect mood and productivity. The discussion transitions into the importance of integrating geological and processing data to optimize mineral extraction processes, emphasizing the need for collaboration between geologists and processing engineers to enhance…

3. 

   S4 · E12 · 23 Dec 2025 · 1 hr

   Volcanoes, Mush, and Mineralization with Mike Stock

   In this episode of GeOCHemISTea , Sam talks with Mike Stock , Professor at Trinity College Dublin, about magma systems from eruption to emplacement. Drawing on work in the Galápagos and Ireland, Mike explores how the same geochemical and petrological processes govern both volcanic activity and ore formation. The conversation focuses on breaking down silos between volcanology and economic geology—highlighting shared tools, concepts, and models that are often studied in isolation. The episode closes with a discussion on batholiths and crustal-scale magma systems, offering a fresh perspective…

4. 

   S4 · E11 · 19 Nov 2025 · 1 hr 1 min

   The mineralogy hidden in your assays with Scott Halley

   This month on GeOCHemISTea, Sam sits down with Scott Halley to talk about extracting meaningful mineralogy from standard four-acid assay data. Scott walks through how the classic MINSQ approach evolved into modern linear-programming methods that handle solid solutions, honor thermodynamics, and produce fast, first-pass mineralogy models. They also dig into ambiguity in geologic interpretation, “cognitive entrenchment” in porphyry systems, and how linking calculated mineralogy to rock physics is helping bridge the gap between geochemistry and geophysics. For this episode we read: MINSQ - a…

5. 

   S4 · E10 · 15 Oct 2025 · 49 min

   Geochemistry Without Borders: A Conversation with Alecos Demetriades

   Alecos Demetriades, applied geochemist and Chair of the IUGS Commission on Global Geochemical Baselines (2024–2028), joins GeOCHemISTea to unpack the Global Geochemical Reference Network (GGRN): why a 160×160 km grid matters, how harmonized sampling/analysis underpins trustworthy baselines, and what QA/QC must look like before interpretation. We touch on FOREGS, leveling national datasets to global references, and practical ways exploration and mining teams can access, use, and contribute to these datasets. Plus: tea stories during Tea Time and why passing knowledge to the next generation…

6. 

   S4 · E8 · 13 Aug 2025 · 59 min

   From Sardis to the lab: a gold assay deep dive with Hugh De Souza

   In this episode of GeOCHemISTea, we're joined by Hugh De Souza to explore the evolution of gold analysis; from 4,000-year-old fire assay traditions to disruptive technologies like photon assay. With over 40 years at research and industry analytical labs and deep experience in mineralogy, geochemistry, and lab innovation, Hugh shares his unconventional path into analytical geochemistry, breaks down the physics behind modern methods, and reflects on what the future holds for gold assay. Whether you're a field geo or into analytical chemistry, this one's for you.

7. 

   S4 · E7 · 9 Jul 2025 · 53 min

   Fine Fractions & Big Discoveries: A Deep Dive into Drainage Geochem with Mary Doherty

   This month on GeOCHemISTea, we are talking about one of exploration geochemistry’s most foundational, and rapidly evolving, methods: stream sediment sampling. Sam is joined by geochemical consultant and educator Mary Doherty, lead author of a 2023 review on stream sediment geochemistry, published in Geochemistry: Exploration, Environment, Analysis . Mary shares a career’s worth of field, lab, and leadership experience, from carrying samples for her USGS geologist father as a child to building geochem training programs for Newmont and ALS, and recently teaching at the Colorado School of…

8. 

   S4 · E5 · 11 Jun 2025 · 1 hr 2 min

   Into the Plume: Hydrothermal Geochemistry and Alvin Adventures with Andy Campbell

   In this episode of GeOCHemISTea, we're diving deep, literally, with Andy Campbell, oceanographer, geochemist, and former senior leader at the U.S. Nuclear Regulatory Commission. Andy takes us back to his PhD days at Scripps Institution of Oceanography, where he conducted some of the earliest geochemical research on seafloor hydrothermal systems in the Guaymas Basin. His work on manganese cycling, water column anomalies, and hydrothermal plume modeling not only helped lay the foundation for modern vent geochemistry, it also offered early insight into how ore deposits might form in…

9. 

   S4 · E4 · 15 May 2025 · 1 hr 30 min

   Geothermal Geochemistry and the Roads Less Taken with Stuart Simmons

   In this episode of GeOCHemISTea , Sam sits down with geochemist and geothermal expert Stuart Simmons to discuss the unpredictable paths that shape a career in geoscience. From early work in epithermal gold systems to pioneering research in geothermal energy, Stuart shares how professional pivots, academic curiosity, and a chance encounter at a pub in New Zealand all influenced his decades-long contribution to both industry and research. The conversation also dives into the geochemistry of geothermal systems, the evolution of isotope studies, and the promise of enhanced geothermal systems…

10. 

    S4 · E4 · 9 Apr 2025 · 1 hr 4 min

    Probing paleorecords to understand future climates with Brittany Hupp

    Join us this month on GeOCHemISTea as we sit down with Brittany Hupp, Assistant Professor at George Mason University in the Department of Atmospheric, Oceanic, and Earth Sciences. Brittany specializes in micropaleontology, sedimentology, and low-temperature geochemistry, exploring ancient climates and ocean conditions to better understand modern environmental challenges. In this episode, Brittany shares her unconventional path into geosciences—from a dairy farm in rural Ohio to oceanic research cruises—and offers practical advice for aspiring geochemists seeking interdisciplinary careers.…