Executive Summary:
Magmatic Systems

CSD is uniquely positioned to promote exploration of magmatic systems that cannot be directly observed at the surface and are only indirectly imaged through geophysical investigations. Below we detail four scientific frontiers for drilling exploration that would significantly advance understanding of how magmatic systems evolve, intrude, and interact with hydrological systems.  The questions are aligned with major challenges identified in recent NASEM reports on the future of Earth science (Earth in Time, 2020 priority questions 3, 5, & 9) and volcanic eruptions (ERUPT, 2017 Grand Challenge 2).

Scientific Questions

1. Volcano stratigraphy of large-volume volcanic structures

What is the life cycle of a magmatic system? Temporal changes in the style and composition of eruption can reveal the evolution of magmatic systems and hazard assessments for individual volcanic systems. Geologic eruptive records are inherently sparse. Early eruptive units are buried by subsequent eruptions at historically active volcanoes and the life cycles of ancient volcanoes are only partially available, depending on the extent of erosion. This not only obscures the eruptive record, but also masks the types of eruptions observed through time within a system, as well as the volume of material transferred from the crust to the surface. Scientific drilling provides critical observations and stratigraphic sequence reconstructions at depth, allowing geologists to better understand how eruptive styles and frequencies, geochemistry, hazards, and processes responsible for the concentration of associated economic resources evolve through time. Thus, scientific drilling can offer insights into the following key questions:

1. How does the magma supply evolve over time?

2. How do magma compositions transition between stages of a volcano’s evolution? Are there predictable transitions?

3. How do erupted melts relate to their sources in the lithosphere? How do they influence the hydrosphere and atmosphere?

2. Magma storage and plumbing systems

At what pressure and temperature are magmas stored in the upper crust? What are the rheological transitions between brittle/ductile crust and magmas? Our understanding of volcano interiors and subsurface architecture is primarily based on satellite imagery, geophysical imaging, field observations, laboratory experiments, and computational modeling. Seismic velocities in the subsurface serve as proxies for physical rock properties and reveal tectonic, magmatic, and hydrothermal activity. Inverse analyses of land surface deformation allow us to estimate the location, geometry, and pressurization or volumetric flux of magmatic plumbing systems at depth. Drilling can provide key testing of geophysical models with independent downhole measurements or observations of extracted core samples. Alternatively, mismatch of geophysical models and downhole or core measurements provides opportunities to re-examine and improve accuracy of geophysical models. Further, drilling into a magma reservoir can provide direct tests for the source of erupted magma and inform thermal, chemical, and volatile budgets critical for understanding energy and mineral resource development of magmatic systems. Therefore, we seek answers to these questions:

1. How reliable are present-day geophysical models of magmatic systems?

2. What can we learn from the mismatch between geophysical models and the real magmatic systems?

3. Geothermal and hydrothermal systems and ore deposits

What is the coupling between magmatic and adjacent hydrothermal systems? The mobilization of gas and volatiles accompanies the migration of magmas during igneous intrusion and volcanic eruption. These processes are impactful for assessing hazards, formation of critical minerals, and energetic expansion. Degassing modulates magma properties such as volume, compressibility, and permeability, which in turn affects our interpretation of volcano deformation signals. The volatiles move from intrusions to surrounding hydrothermal systems where they are critical to the formation of ore deposits, contact metamorphism, and geothermal energy sources. Drilling into these regions provides opportunities to systematically inspect the interface between magmas and hydrothermal systems. Moreover, seismic signals such as volcano-tectonic events, long-period earthquakes, tremor and spasmodic bursts can have cryptic origins. Understanding generation of these varied signals requires improved models of how magma migrates, flows, fractures, and anneals during ascent. Drilling will provide key information for understanding the critical region of magma-hydrothermal transition.

1. How do temperature, pressure and composition of fluids vary across the magma-hydrothermal interface and how does this interface evolve over time?

2. Can volcano deformation be linked to magma degassing and can we use this link to better forecast volcanic hazards?

3. Can we investigate key magma-hydrothermal transition zones for gradients in temperature, pressure, chemistry, mineralogy and isotopic signature?

4. Faults and magmas

How do magma bodies and their exsolving volatiles perturb the regional tectonic stress field and cause earthquakes?

Alignments of continental volcanic systems and fault zones are common and their coupled evolution underlies a variety of geohazards. Yet, little is known about how the structure and dynamics of these faults are influenced by fluxes of magmatic volatiles and heat. The magmatic system provides pressurization, thermal, and chemical driving mechanisms that interact with the surrounding crust modulating stress, strain, and porous flow. In its simplest form, pressurization of a magmatic system changes the stress and fluid pressure–and thus stability--of nearby faults. Over long time scales, magmatic volatiles and heat can modify crustal rheology and alter minerals and mechanical strength within the fault zone. Permeability is higher along rather than across faults; thus, fault zones may exert control on pathways for magmatic fluid migration. Over shorter time scales, magmatic volatiles and heat affect fault zone structure and dynamics by influencing pore pressures, which may have consequences for earthquake cycle deformation and partitioning of slip across the spectrum of seismic to aseismic modes. Drilling into fault regions suspected to be influenced by magma bodies would test these hypotheses and enable comparison with prior fault zone drilling results from non-magmatic settings. Drilling would reveal the extent to which magmatic fluids alter faults, forming a critical comparison to sampling of faults in other settings.

1. How do stress and pore pressure variations of magmatic systems influence fault stability?

2. How do chemically active volatiles from magmatic systems change the mechanical, fluid transport, thermal, and chemistry properties of surrounding faults?

Frontier Resources: High temperature drilling with in-situ instruments, industry partnerships, and societal impacts

The energy industry has made tremendous advances in drilling technology and applications during the past few decades. Scientific drilling into magmatic systems stands to greatly benefit from these advances that include new dimensions of directional drilling and high temperature drilling and sensors capable of sampling the entire magmatic system from brittle shallow crust, through the complex hydrothermal transition, and into the magma reservoir. Scientific and industry partnerships may be the key to implementing these advancements for the greater benefit of both sectors. Additionally, successful scientific drilling should clearly illustrate the greater societal impacts to better justify the program. This could be accomplished by ensuring that targets for scientific drilling in magmatic systems include stakeholder support from cross-cutting academic, government, and industry sectors.

Suggested Citation

Myers, M., Masterlark, T., Abers, G Bizimis, M., Black, B., Clarke, A., DePaolo, Eddy, M.P., D., Eichelberger, J., Finlayson, V., Fischer, T., Jackson, M., Konrad, K., Lowenstern, J., Pistone, M., Poland, M., Schmandt, B., 2024. Magmatic Systems Science Planning for Continental Drilling and Coring 2024. https://sites.google.com/umn.edu/csdscienceplanning/home/magmatic-systems-executive-summary

References                                                                     

National Academies of Sciences, Engineering, and Medicine. 2017. Volcanic Eruptions and Their Repose, Unrest, Precursors, and Timing. Washington, DC: The National Academies Press. doi: https:// doi.org/10.17226/24650.                                                              

National Academies of Sciences, Engineering, and Medicine. 2020. A Vision for NSF Earth Sciences 2020-2030: Earth in Time. Washington, DC: The National Academies Press. https://doi.org/10.17226/25761.     

Magmatic Systems Working Group

Geoffrey Abers, Cornell University

Michael Bizimis, University of South Carolina

Ben Black, Rutgers University

Amanda Clarke, Arizona State University

Donald DePaolo, University of California Berkeley

Michael P. Eddy, Purdue University

John Eichelberger, University of Alaska Fairbanks

Val Finlayson, University of Maryland

Tobias Fischer, University of New Mexico

Matt Jackson, University of California Santa Barbara

Kevin Konrad, University of Nevada Las Vegas

Jacob Lowenstern, United States Geological Survey

Tim Masterlark, South Dakota School of Mines

Madison Myers, Montana State University

Mattia Pistone, University of Georgia

Michael Poland, United States Geological Survey

Brandon Schmandt, University of New Mexico

Magmatic Systems Community Editors

Meghan Guild, Arizona State University

Kayla Lacovino, NASA

Jeffrey Johnson, Boise State University

Peter Kelemen, Lamont-Doherty Earth Observatory Columbia University

Katie Kelley, University of Rhode Island Graduate School of Oceanography

Adam Kent, Oregon State University

Vali Memeti, California State University Fullerton

Carolina Muñoz-Saez, University of Nevada Reno

Terry Plank, Lamont-Doherty Earth Observatory Columbia University

Diana Roman, Carnegie Institution for Science

Donald Thomas, University of Hawaii

Stephen Turner, University of Massachusetts Amherst

Kevin Ward, South Dakota School of Mines and Technology