SDSM&T Geology & Geological Engineering

Kudos to Dr. Paterson!

Our photo of the week comes from Josue R Laboy, one of the 2025 Photowalk winners, who captured this image of South Dakota Mines emeritus professor Colin Paterson, showing a set of minerals and rocks to a Neutrino Day attendee.

Mark your calendar for Neutrino Day 2026 on July 11 and explore all sorts of rocks, minerals, and fossils from the Museum of Geology at South Dakota Mines!

Kudos to Dr. Ustunisik!

Mines Professor’s NSF and NERC Award Could Unlock Carbon Isotope Mystery Deep Within Earth’s Heterogeneous Mantle:

A new international research project led by South Dakota Mines researcher Gokce Ustunisik, Ph.D., associate professor of geology and geological engineering, and collaborators at the University of Cambridge, aims to answer one of Earth science's most fundamental questions: how carbon is stored and released from the planet’s different mantle reservoirs?

Carbon is essential to life, but most of Earth’s carbon is not at the surface or in the atmosphere; it is locked far below in the planet’s mantle, a vast, slowly moving body of rock beneath the crust. Understanding how carbon moves through the deep Earth system could reshape how scientists better understand the impact of volcanic activity and develop better models for the evolution of ocean chemistry and climate.

Learn more: https://lnkd.in/g5a6Z6Sr

GGE and MEM Department's end-of-the-year potluck.

A great time to celebrate the end of the spring semester with some good food as everyone is getting for final project presentations and final exams.

A big thank you to Cleo and Jennifer for getting everything organized!

A special thanks to Cleo and Dr. Katzenstein for sharing their pictures!

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This week in lab...

Dr. Waldien's GEOL 322L (Structural Geology lab) students were at M-Hill measuring the orientation of bedding.

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Notice of Thesis Defense
MS Candidate: Jacob Sanders
Program: Geology and Geological Engineering
Title: Power Law Creep and Time Hardening Parameters Calibrated with Machine Learning
When: Thursday, April 16, 2026, at 9:30 am
Where: Nucor Mineral Industries Building, Room 201
Sanders’s research was conducted under the guidance of Major Professor Dr. Timothy Masterlark.

Abstract:
A salt cavern disrupts lithostatic equilibrium conditions. Pressurization can mitigate, but not eliminate, the deviatoric stresses in the salt surrounding the cavern. Laboratory experiments reveal the time-dependent deformation of salt in response to deviatoric stress and creep models describe this relationship. Creep parameters are calibrated to the laboratory data. These parameters inform geomechanical models that provide important predictions for the maintenance and long-term sustainability of salt caverns. We use Machine Learning to estimate strategic creep parameters for laboratory experiments on Avery Island salt. A key innovation of this study is to determine the minimum complexity required, Occam’s Razor, to predict the data from a probabilistic perspective. This approach contrasts with conventional creep models having numerous parameters intended to account for a multitude of micromechanical processes. Instead, we treat the system as a continuum and let the data dictate the required complexity. We assume the uniaxial strain caused by loading is described by a general creep power law with time-hardening: de/dt= Asntm, where e and s are the uniaxial strain and stress, respectively, and A, n, and m are calibration parameters. Integration of this creep law yields the basis function for time dependent creep: e(t)=Asn(m+1)-1t(m+1). We evaluate the predictive performance for three model configurations of increasing complexity: First, A is adjustable and m=0 and n=1, Second, A and m are adjustable and n=1, and Third, A, m, and n are adjustable. For all three complexity configurations, A is estimated as the least squares solution. A Machine Learning algorithm with Monte Carlo sampling estimates the corresponding values for m and finally both m and n in the sequentially complex configurations. The analysis quantifies parameter estimates and uncertainties, for the sequential model complexity configurations. Results indicate that the simplest model cannot adequately predict the data. Models having the additional complexity of both adjustable A=4.78x10-13 and m=-0.7757 can precisely recover the strain data for a single loading episode but fail to adequately simulate a two-stage loading sequence. Preliminary results suggest that the most complex model configuration, with the three adjustable parameters and the full flexibility of the time-hardening power law, adequately simulates creep for multi-stage experimental loading conditions. We verify the reliability of these results against independent strain data from an additional loading sequence conducted on the salt core.

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Notice of Dissertation Defense
PhD Candidate: Olivia Maltos-Daynes
Program: Geology, Geological Engineering, and Mining Engineering
Title: The Variability of Magmatic Processes Occurring at Depth Across the Global Mid-Ocean Ridge System
When: Wednesday, April 15, 2026, at 10:30 am
Where: Nucor Mineral Industries Building, Room 201
Daynes’ research was conducted under the guidance of Major Professor Dr. Gokce Ustunisik

Abstract:
Mid-ocean ridge basalts (MORB) are the product of mantle melting followed by a complex set of processes including mixing and differentiation. These processes erase and blend the primary geochemical signature of the array of mantle melts during transit through the upper mantle and crust. To reconstruct the primary magmatic signature, this dissertation used the geochemistry of melt inclusions (MI) which are small pockets of melt entrapped at the time of crystallization of the host minerals. The focus has been on MI from plagioclase ultraphyric basalts (PUB), a subset of MORB lavas. The composition of plagioclase-hosted MI (PHMI) from PUB were examined as a function of the geophysical and geochemical characteristics of mid-ocean ridge (MOR) lavas. This dissertation also explored how that information can be interpreted with olivine hosted-MI (OHMI), abyssal peridotites and erupted lavas from other sample locations within the MOR and Iceland.
The first investigation focused on analysis of plagioclase megacrysts and their MI from the Garrett Fracture Zone, a region noted for its depleted compositional signature (CO2 undersaturated; high Ti/Zr, low La/Sm). PUB lavas were analyzed for major, trace, and volatile element concentrations and exhibited high CO2 and depleted incompatible trace element compositions – even more depleted than the previously reported results using analysis of glass and OHMI.
The second investigation was based on twelve globally distributed PUB samples. The results documented no correlation between the identity or extent of differentiation processes (e.g., crystal fractionation, degassing, mixing) and spreading rate (e.g., ultra-slow to intermediate), tectonic setting (e.g., on-axis, off-axis seamount, pull-apart basin, or plume-influenced), or crustal thickness. All sample locations in this globally distributed dataset captured melt in PHMI with Zr < 5 ppm and Ti ~ 2000 ppm regardless of the ridge characteristics. A subset of incompatible trace element depleted PHMI also recording CO2 concentrations up to ~5500 ppm despite having no v***r bubbles in the MI - normally a characteristic of CO2 undersaturation. Samples with the lowest incompatible trace element concentrations contain CO2/Ba up to ~ 3500, ratio values which are not seen in OHMI and glass within MOR setting or OHMI and PHMI from Iceland. Two processes were identified that allow for PUB plagioclase megacrysts to entrap melts not sampled by other phases in the MOR or Iceland including: 1) a plagioclase pseudoazeotrope which enables plagioclase to crystallize at conditions when olivine is being resorbed, and 2) a density filter which preferentially allows for plagioclase enrichment. The incompatible trace element depleted liquids captured in PUB PHMI overlap in composition with the liquids in equilibrium with abyssal peridotite clinopyroxene, consistent with them representing near-primary melts.
The final investigation focused on the veracity of the CO2 measurements which depend on our confidence in the structural integrity of MI. Petrographic analysis of two PUB thin sections documented that the pressure (P) and temperature (T) changes during ascent may be recorded in the form of physical deformation of the MI and the plagioclase host. One sample contained glassy PHMI and was inferred to have experienced adiabatic (high ΔP/ΔT) conditions as the megacryst traveled to the surface. The pressure differential between the MI (PMI) and the surroundings (Pexternal) reached a point where the plagioclase host crystals fracture. A second sample which contained fully crystallized PHMI experienced polybaric (low ΔP/ΔT) transport. The concurrent drop in P and T caused crystallization of the MI, lowering the PMI which prevented host plagioclase fracturing.

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Notice of Thesis Defense
MS Candidate: Henry Aas
Program: Geology and Geological Engineering
Title: Modeling and Optimizing Borehole Thermal Energy Storage System Under Groundwater Flow
When: Tuesday, April 14, 2026, at 12:00 pm
Where: Nucor Mineral Industries Building, Room 201
Aas’s research was conducted under the guidance of Major Professor Dr. Liangping Li

Abstract:
This study investigates the optimization of borehole heat exchanger flow rates in borehole thermal energy storage (BTES) systems under groundwater flow conditions to enhance thermal recovery and reduce heat loss. System performance is governed by both design parameters, such as borehole spacing and flow rates, and hydrogeological factors, particularly groundwater velocity, which is often neglected despite its significant impact on subsurface heat transport. A
Genetic Algorithm coupled with Finite Element Modeling (FEM) was used to simulate realistic geologic conditions across a range of hydraulic gradients and to identify optimal operating strategies. Results indicate that optimized flow rates improve thermal recovery efficiency by approximately 4% in moderate and 3% in high groundwater flow conditions. Application to a heterogeneous subsurface model yields improvements of up to 4.8% and 3.53%, although gains are partially reduced by increased heat loss under certain conditions. These findings highlight the importance of incorporating groundwater flow into BTES design and demonstrate that optimization techniques can significantly improve system performance, supporting more reliable and flexible integration of renewable thermal energy into energy systems.

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GGE Research Highlights...

Please check out the latest paper about Borehole Thermal Energy Storage Systems (BTES) by the graduate student Michael Osei-Boateng under the supervision of Dr. Liangping Li. In this paper, FEFLOW was used to model BTES system, and parallel and serial borehole connections are assessed in terms of thermal recovery and economic performance.

This work was carried out in collaboration with geothermal engineers Matthew Minnick and Haiyan Zhou from RESPEC, with financial support provided by National Science Foundation (NSF) and U.S. Department of Energy (DOE) through the NSF-DOE Geothermal INTERN program.

Michael Boateng graduated in May 2025 and is currently working as a geotechnical engineer at Freeport-McMoran.

Read the full paper here: https://rdcu.be/e99Ms

https://link.springer.com/article/10.1007/s11004-026-10272-2

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Friday Seminar

https://www.sdsmt.edu/academics/academic-departments/geology-and-geological-engineering/index.html