Heath Stanfield

All Publications

• Decadal-Scale Hydrothermal Alteration of Basalt: Implications for Long-Term Reactivity in Subsurface Technologies ACS EARTH AND SPACE CHEMISTRY Gibson, M. N. M., Lamberti, V. R., Nienhuis, E. T., Stanfield, C., Teng, Y., Chopra, H., Marcial, J., Vo, T., Dang, S. T., Miller, Q. R. S., Schaef, H. 2026; 10 (7): 1732-1741

  View details for DOI 10.1021/acsearthspacechem.6c00057

  View details for Web of Science ID 001793709800001

• Chelation-Driven Chemistry Controls Dissolution Pathways for Facile Critical Mineral Recovery from Ultramafic Resources. JACS Au Krishnan, K., Motkuri, R. K., Yan, K., Stanfield, C. H., Polites, E. G., Teng, Y., Shin, S. H., Miller, Q. R., Schaef, H. T., Lahiri, N. 2026; 6 (5): 2743-2752

  Abstract

  The efficient recovery of critical minerals, such as nickel (Ni) and manganese (Mn) from the subsurface, is of vital importance, given their role in modern technologies ranging from energy storage to advanced alloys. This study presents a chelation-driven strategy to enhance critical mineral recovery from ultramafic rocks under ambient pressures and systematically evaluates key controls on extraction processes for the first time. Using EDTA and 1,3-PDTA as model chelating agents, we show that the stability of the metal-ligand chelate exerts first-order control of mineral-fluid interfacial reactivity and ring strain with metal and, consequently, net dissolution rates. To further highlight the ability for optimization, fluid exchange and variation of the fluid-to-rock ratio experiments were conducted, revealing tunable controls for engineering recovery. Under optimized conditions, Ni and Mn extraction efficiencies reach ∼ 95% and ∼ 80%, respectively. When extrapolated to the Twin Sisters Formation in the United States, these results correspond to recovering over 26 times the current global Ni production, and ∼ 1.5 times of the current global Mn production, even if only 5% of the formation were reacted. From both in situ and ex situ mining perspectives, this work demonstrates that chelation chemistry provides a tunable, transformative pathway for unlocking mineral extraction from unconventional resources while mitigating supply chain vulnerabilities.

  View details for DOI 10.1021/jacsau.5c01623

  View details for PubMedID 42212079

  View details for PubMedCentralID PMC13213395

• Earth as a Reactor: Carbon Mineralization Geochemistry in the Context of Emerging Subsurface Energy and Resource Technologies CHEMICAL REVIEWS Miller, Q. R. S., Bartels, M. F., Chopra, H., Depp, C. T., DiRaddo, S. G., Gibson, M. N. M., Lahiri, N., Lamberti, V. R., Rivera, N., Maier, K. L., Murchland, M. A., Nienhuis, E. T., Parisi, J., Polites, E. G., Stanfield, C., Steup, K. J., Teng, Y., Villante, M. A., Yan, K., Schaef, H. 2026; 126 (10): 5713-5754

  Abstract

  The Earth's crust contains reactive, igneous reservoirs that can be utilized to turn atmospheric CO2 into new carbonate minerals. Carbon mineralization technology relies on the reactions between crustal reactants (rock, water, and biota) and injected CO2 to release divalent cations that can participate in the precipitation of new carbonate minerals. Field CO2 injection tests in mafic-ultramafic lithologies around the world have opened a window into the reactive potential of the subsurface. Knowledge and technology gained from the decades of carbon mineralization research will push forward efforts in unlocking innovative ways to approach subsurface critical mineral resources, hydrogen generation, geothermal energy, water resource management, waste storage, gas storage, and hydrocarbon extraction. Our review describes a holistic view of subsurface mafic-ultramafic reservoirs, carbon mineralization reactions, field tests, and future opportunities for using the subsurface Earth as a Reactor.

  View details for DOI 10.1021/acs.chemrev.5c00716

  View details for Web of Science ID 001758445800001

  View details for PubMedID 42090541

• Critical mineral recovery and carbon storage potential at the Tamarack intrusive complex INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL Chopra, H., Stanfield, C., Bartels, M. F., Lahiri, N., Marcial, J., Nienhuis, E. T., Mudrovska, I., Fillion, M., Rush, R., Hunt, T., Morton, N., Van Wyk, S., Devasagayam, C., Miller, Q. R. S., Schaef, H. 2026; 153

  View details for DOI 10.1016/j.ijggc.2026.104658

  View details for Web of Science ID 001754603700001

• Cation Site Occupancy in Natural Ferroan Double Carbonates via Mössbauer and Fe K-Edge X-ray Absorption Spectroscopy. Inorganic chemistry Boglaienko, D. V., Prange, M. P., Stanfield, C. H., Mergelsberg, S. T., Latta, D. E., Li, X., Kerisit, S. N., Schaef, H. T., Rosso, K. M., Miller, Q. R. 2026; 65 (11): 5986-5994

  Abstract

  Double carbonates are minerals with a calcite-type structure with alternating cation layers composed of Ca and Mg/Fe coordinated by carbonate groups. While the perfectly ordered AB-stacked crystal is the thermodynamically most stable configuration, natural mineral formation pathways can leave signatures through kinetically trapped disorder, such as AB antisite cation substitutions. This study probes the degree of cation ordering in naturally occurring double-carbonate samples. In particular, the dependence of structural order on the distribution of Fe A and B crystallographic sites (the A site is the Ca layer, and the B site is the Mg/Fe layer) is examined. Mössbauer, X-ray diffraction, X-ray absorption spectroscopies (both the X-ray absorption near edge structure, XANES, and extended X-ray absorption fine structure, EXAFS), and energy-dispersive X-ray spectroscopy were used to collect a comprehensive experimental data set, which we interpret using density functional theory to elucidate the structural effects of cation disorder. Our results show that the A (nominally Ca) site can host a relatively high Fe fraction. We discuss the implications in terms of mineral formation.

  View details for DOI 10.1021/acs.inorgchem.5c05312

  View details for PubMedID 41802235

• Nanoscale Interfacial Reactivity in Tamarack Peridotite: Insights for In Situ Critical Mineral Recovery ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS Bartels, M. F., Miller, Q. R. S., Li, X., Stanfield, C., Cao, R., Marcial, J., Nienhuis, E. T., Fillion, M., Rush, R., Sauve, M., Schaef, H. 2026; 13 (2): 302-309

  View details for DOI 10.1021/acs.estlett.5c01088

  View details for Web of Science ID 001664818300001

• Greenhills Dunite Subsurface Reaction Kinetics in a Global Mafic-Ultramafic Context. Environmental science & technology Stanfield, C. H., Miller, Q. R., Cao, R., Nienhuis, E. T., Marcial, J., Palmer, M. C., Lahiri, N., Bartels, M. F., Pyott, L., Ritchie, T. W., Schaef, H. T. 2025; 59 (44): 23773-23785

  Abstract

  The strong impetus to reduce emissions from fossil fuels has led to the development of abatement technologies, such as in situ carbon storage via mineralization in mafic and ultramafic rocks. While field-scale implementation of carbon storage in basaltic reservoirs is currently ongoing in Iceland, only pilot-level injections have been conducted in highly reactive ultramafic deposits in the Middle East. The South Island of New Zealand hosts numerous and extensive ultramafic rock bodies, including the intrusively deposited Greenhills Dunite within the Greenhills Ultramafic Complex. In this study, we evaluate the potential for carbon storage via in situ mineralization in Greenhills Dunite. An experimental matrix of batch reactions at subsurface temperatures and pressures shows a high carbonation extent across different conditions and size fractions, with the reaction products largely consisting of magnesite with evidence for iron incorporation. A 10-day high-pressure in situ X-ray diffraction experiment shows that the incipient stage of the reaction is dominated by brucite carbonation followed by the slower kinetics of olivine carbonation. The kinetics of these reactions were then compared to those in the broader (ultra)mafic carbonation literature that includes basalt and basaltic glass carbonation experiments. Overall, these results show potential for field-scale in situ mineralization deployment in the Greenhills Ultramafic Complex and highlights the potential for CO2 storage in mafic-ultramafic rocks around the globe.

  View details for DOI 10.1021/acs.est.5c07444

  View details for PubMedID 41092275

• CO₂-Based Leaching of Sulfidic Peridotite Drives Critical Mineral Mobilization and Carbonate Precipitation ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS Murchland, M. A., Miller, Q. R. S., Nagurney, A. B., Stanfield, C., Lahiri, N., Silverstein, J. A., Teng, Y., Nienhuis, E. T., Engelhard, M. H., Mulcahy, C., Schaef, H. 2025; 12 (9): 1252-1263

  View details for DOI 10.1021/acs.estlett.5c00603

  View details for Web of Science ID 001545756600001

• Interfacial Hydrophilicity Controls Mineral Transformation Outcomes for Enstatite and Amorphous MgSiO₃ ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS Hardee, L., Schaef, H., Barpaga, D., Stanfield, C., Crum, J. V., Anovitz, L. M., Rosso, K. M., Miller, Q. R. S., Aguila-Ames, B. 2025; 12 (8): 951-962

  View details for DOI 10.1021/acs.estlett.5c00487

  View details for Web of Science ID 001524584900001

• Structure-Composition Relationships in the Dolomite-Ankerite-Kutnohorite Series Reveal Distinctions Based on Growth Conditions and Cation Ordering CRYSTAL GROWTH & DESIGN Stanfield, C., Morfin, A. M., Kerisit, S. N., Prange, M. P., Lahiri, N., Schaef, H., Rosso, K. M., Miller, Q. R. S. 2025; 25 (12): 4253-4262

  View details for DOI 10.1021/acs.cgd.5c00142

  View details for Web of Science ID 001497566300001

• Structure-Composition Relationships for Mg-Ni and Mg-Fe Olivine ACS EARTH AND SPACE CHEMISTRY Morfin, A. M., Stanfield, C., Murchland, M. A., Bartels, M. F., Nagurney, A. B., Miller, Q. R. S., Schaef, H. 2024; 8 (9): 1713-1724

  View details for DOI 10.1021/acsearthspacechem.4c00044

  View details for Web of Science ID 001295124400001

• Carbon Mineralization and Critical Mineral Resource Evaluation Pathways for Mafic-Ultramafic Assets ACS EARTH AND SPACE CHEMISTRY Stanfield, C., Miller, Q. R. S., Battu, A. K., Lahiri, N., Nagurney, A. B., Cao, R., Nienhuis, E. T., Depaolo, D. J., Latta, D. E., Schaef, H. 2024; 8 (6): 1204-1213

  View details for DOI 10.1021/acsearthspacechem.4c00005

  View details for Web of Science ID 001252274700001

• Parts-Per-Million Carbonate Mineral Quantification with Thermogravimetric Analysis-Mass Spectrometry. Analytical chemistry Bartels, M. F., Miller, Q. R., Cao, R., Lahiri, N., Holliman, J. E., Stanfield, C. H., Schaef, H. T. 2024; 96 (11): 4385-4393

  Abstract

  Mitigating the deleterious effects of climate change requires the development and implementation of carbon capture and storage technologies. To expand the monitoring, verification, and reporting (MRV) capabilities of geologic carbon mineralization projects, we developed a thermogravimetric analysis-mass spectrometry (TGA-MS) methodology to enable quantification of <100 ppm calcite (CaCO3) in complex samples. We extended TGA-MS calcite calibration curves to enable a higher measurement resolution and lower limits of quantification for evolved CO2 from a calcite-corundum mixture. We demonstrated <100 ppm carbonate mineral quantification with TGA-MS for the first time, an outcome applicable across earth, environmental, and materials science fields. We applied this carbonate quantification method to a suite of Columbia River Basalt Group (CRBG) well cuttings recovered in 2009 from Pacific Northwest National Laboratory's Wallula #1 Well. Our execution of this new combined calcite and calcite-corundum calibration curve TGA-MS method on our CRBG sample suite indicated average carbonate contents of 0.050 wt % in flow interiors (caprocks) and 0.400 wt % in interflow zones (reservoirs) in the upper 1250 m of the Wallula #1 Well. By advancing our knowledge of continental flood basalt-hosted carbonates in the mafic subsurface and reaching new TGA-MS quantification limits for carbonate minerals, we expand MRV capabilities and support the commercial-scale deployment of carbon mineralization projects in the Pacific Northwest United States and beyond.

  View details for DOI 10.1021/acs.analchem.3c03936

  View details for PubMedID 38407067