In this episode of GeOCHemISTea, Sam talks with Dr. Brenda Bowen, Professor of Geology and Geophysics at the University of Utah, about using remote sensing to understand geochemistry at the scale of entire landscapes.

Brenda traces her work from the Navajo Sandstone and ancient fluid-flow systems to modern salt flats, desert environments, and Mars analogs. We explore how multispectral and hyperspectral data can map mineralogy, how minerals preserve records of water and environmental change, and how surface halite can even provide clues about groundwater depth.

We also talk about interdisciplinary science, unexpected career paths, fieldwork, and why some of the most interesting discoveries happen when geochemistry connects with hydrology, microbiology, ecology, and remote sensing.For this episode we read:

Multispectral Surface Reflectance as an Indicator of Groundwater Depth for Salt Crust Systems: Insights From the Bonneville Salt Flats, Utah (Radwin et al., 2026)

Bleaching of Jurassic Navajo Sandstone on Colorado Plateau Laramide highs: Evidence of exhumed hydrocarbon supergiants? (Beitler et al., 2003)

Southwestern Australia Acid-Saline Mineralogy: Observations From Reflectance Spectroscopy (Radwin et al., 2023)

Fracture-focused fluid flow in an acid and redox-influenced system: diagenetic controls on cement mineralogy and geomorphology in the Navajo Sandstone (Bell and Bowen, 2014)

Decadal‐Scale Trajectories of Land Cover Change Along the Colorado and San Juan Rivers in Response to Declining Water Storage in Lake Powell Reservoir (Kasprak et al., 2026)

Mapping mineralogy in evaporite basins through time using multispectral Landsat data: Examples from the Bonneville basin, Utah, USA (Radwin and Bowen, 2020)

Shrinking salt crusts of the Bonneville Basin, Utah: Observations from multispectral remote sensing (2025)

Is the next generation of mineral discoveries really hiding at extreme depths, or have we overlooked opportunities much closer to the surface?

In this episode, Sam sits down with returning guest Mark Arundell, geoscientist and geochemical consultant, to challenge one of exploration's most widely accepted assumptions: that bigger discoveries require deeper drilling. Together they explore the "fallacy of the deep," discuss why statistics matter when interpreting exploration success, and examine how integrating geology, geochemistry, geophysics, and modern analytical techniques can unlock value from legacy datasets. They also share insights from consulting, near-miss exploration, and why asking better questions often leads to better discoveries.

In this episode:

• Why the "deeper is better" narrative became so influential
• Average vs. median discovery depths and why the difference matters
• The untapped potential of the first 100 metres
• Using modern multi-element geochemistry to reinterpret historic data
• How legacy drill core and pulps can create new exploration opportunities
• The psychology of exploration and why expensive targets often seem more attractive
• When deep drilling is justified—and when it is not
• Practical advice for designing smarter exploration programs

As always, we bridge our intro and geochem sections with Tea Time, where Mark shares a memorable airport security story and Sam offers one of her favorite travel hacks.

For Episode 51, the tables are turned as Imdex Chief Geologist and Technologist Dave Lawie takes over hosting duties and puts Sam in the hot seat.

Fresh from the SME Current Trends in Mining Finance conference in New York City, Dave and Sam discuss the growing disconnect between how mining projects are evaluated financially and how they actually behave technically. From resource models and geometallurgy to critical minerals, permitting, and project risk, they explore why geology, mineralogy, metallurgy, and geochemistry remain central to project success.

The conversation also looks at Sam's path into geochemistry, the origins of GeOCHemISTea, and the role mentorship has played throughout her career.

• How Sam found her way into geochemistry
• Why technical risk is often overlooked in mining finance
• The realities of critical mineral recovery
• Geometallurgy, mineralogy, and project valuation
• Where AI may (and may not) help the industry
• Why mining needs better conversations between technical and financial teams

A candid discussion about the assumptions, risks, and opportunities that sit between a discovery and a successful mine.

• SME Current Trends in Mining Finance Conference
• Imdex
• LKI Consulting

For our 50th episode of GeOCHemISTea, we’re doing something a little different... a panel discussion that brings together two very different perspectives on one deceptively simple problem: levelling geochemical data.

Joined by a government survey geochemist, Pedro Acosta-Gongora, and a mathematical geologist, Tom Carmichael, this conversation digs into what levelling really means in practice, why it’s become standard in regional datasets, and where it can quietly distort the geological signal. From legacy data and batch effects to the tension between clean maps and real-world noise, this episode explores the intersection of applied geochemistry and data science.

If you’ve ever worked with multiple datasets and wondered “can I actually trust this?...” this panel is for you.

For this episode we read:

Exploratory data analysis of geochemical exploration data (Arne and Garrett, 2026)

Data Leveling of Multi-Map Geochemical Exploration Data Using Compositional Data Analysis: A Case Study from the Baiyinchagan-Maodeng Area, Inner Mongolia, China (Tang et al., 2025)

Levelling of multi-generational and spatialyy isolated geochemical surveys (Main and Champion, 2022)

G-BASE data conditioning procedures fro stream sediment and soil chemical analyses (Lister and Johnson, 2005)

In this episode of GeOCHemISTea, Sam sits down with Gabe Bowen to explore the world of forensic isotope geochemistry and the power of isoscapes.

From identifying where someone has lived, to reconstructing movement through hair and teeth, isotopes are becoming a powerful investigative tool—bridging geochemistry, ecology, and forensic science.

They break down:

• What forensic isotope geochemistry actually is (and what it isn’t)
• How isoscapes turn isotope data into geographic maps
• Why hydrogen, oxygen, strontium, and sulfur matter
• How hair, teeth, and bone record different parts of a life story
• The role of geochemistry in solving cold cases and tracking animal movement

And yes... there’s a detour into true crime, salmon migration, and what isotopes might reveal about your last vacation.

This episode highlights how geochemistry extends far beyond rocks and into real-world problems with immediate impact.

🎧 If you’ve ever wondered how geochemistry can help answer the question “Where did this come from?”... this one’s for you.

For this episode we read:

Human tissue oxygen and strontium isotope values in North America: A data compilation and assessment for forensic geolocation (Verostick et al., 2025) BITS: A Bayesian Isotope Turnover and Sampling model for strontium isotopes in proboscideans and its potential utility in movement ecology (Yang et al., 2023)

Isoscapes: Understanding movement, pattern, and process on Earth through isotope mapping (West et al., 2010)

Multi-isotopes in human hair: A tool to initiate cross-border collaboration in international cold-cases (Batalle et al., 2022)

This episode of GeOCHemISTea explores cobalt cycling, critical metals, and why geochemists need to think beyond bulk chemistry to understand how elements behave in surface environments. Sam is joined by Owen Missen, lecturer in environmental geology at the University of Tasmania and researcher with CODES, whose work focuses on the environmental geochemistry and mineralogy of elements like cobalt and tellurium.

The conversation explores why cobalt matters in modern technology, how nanoscale particles are changing the way we think about metal mobility, and what this means for environmental risk around mine waste and legacy sites. Owen also shares insights from Tasmania’s mining legacy, including the Mount Lyell–Macquarie Harbour system, and reflects on why understanding metals at the right scale matters for better mining and environmental decisions.

For this episode we read:

Natural cobalt–manganese oxide nanoparticles: speciation, detection and implications for cobalt cycling (Missen et al., 2024)

Simon Bolster joins GeOCHemISTea to unpack what actuallymakes 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 industry “silver bullets” (MMI, calcrete, ultrafines) and why blanket adoption creates false confidence. Finally, he explains how DetectOre upgrades gold from ppb-scale field chemistry into something actionable and fast, by leaching and concentrating gold onto a collector device that can be read by pXRF, enabling real-time decision-making while rigs are still turning.

For this episode we read:

Valuing time and how some of the latest technologies arecompressing time to fast track and de-risk new discoveries and mines (Bolster, 2025)

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 decision-making and reduce waste in mining operations.

As the conversation unfolds, Mohsen shares his journey from mining exploration to mineral processing, highlighting the significance of automation and AI in modern mining practices. He advocates for a holistic approach to mining that considers the entire lifecycle of minerals, from extraction to recycling, and stresses the importance of leveraging existing geological data to improve processing efficiency. The episode concludes with a forward-looking perspective on the future of mining, envisioning a fully integrated system that not only maximizes resource extraction but also prioritizes environmental sustainability and circular economy principles.

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 on how modern volcanology can inform interpretations of ancient intrusions and mineralized systems, making it relevant for volcanologists and economic geologists alike.

For this episode we read:Integrated Petrological and Geophysical Constraints on Magma System Architecture in the Western Galápagos Archipelago: Insights From Wolf Volcano (Stock et al., 2018)

Late-stage volatile saturation as a potential trigger for explosive volcanic eruptions (Stock et al., 2016)

Cryptic evolved melts beneath monotonous basaltic shield volcanoes in the Galápagos Archipelago (Stock et al., 2020)

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 least squares spreadsheet method for calculating mineral proportions from whole rock major element analyses (Herrmann and Berry, 2002)