Earth Sciences at DUSEL: Ideas and Progress to Date

1. Earth Sciences at DUSEL: Ideas and Progress to Date Eric Sonnenthal & Brian McPherson

2. Earth Science Working Groups • Coupled Processes (Hydrology, Geochemistry, Petrology) • Rock Mechanics and Geophysics Note: Engineering is an integral of Earth Sciences

3. Progress and Continuing Discussion • Participants have generally agreed on the unique attributes of DUSEL for Earth Sciences: Unprecedented experiments covering a wide range of spatial and temporal scales Transparent Earth: Visualization, probing the Earth in 3-D Life in “extreme environments, ancient life” • Participants have not agreed on: “Societal benefits” (resources, waste management, industry needs) vs “Fundamental science and engineering” “Hard rock” vs “Soft rock” • Participants need to define still: Why go deep - Specific criteria for experiments unique to DUSEL (depth - fluid pressure, temperature, stress, rock characteristics) Infrastructure needs for experiments, compatibilities, etc.

4. Black Hills Salt Creek Anticline 2000 Oil or Gas Well Elevation (m) SL -2000 Data collected at bottom of borehole. Vertical Exaggeration x 16 -4000 Powder River Basin, Wyoming Question: What’s the major benefit to Earth Science of “going underground”? One Typical Approach to Subsurface Investigations: Use drill-hole data with computer model simulations

5. Proposed New Approach: Develop a US laboratory and observatory underground, inside the earth. Much like surgery permits a physician to examine internal bones and organs recognized on X-rays or CAT scans, NUSL will be a fully instrumented, dedicated laboratory and observatory for scientists and engineers to examine Earth’s interior. Courtesy: URL at Atomic Energy of Canada Ltd

6. From NSF EarthLab Report Surface laboratories for core, water, gas, and microbial analyses, experiments, and archives

7. From NSF EarthLab Report Deep Flow and Paleoclimate Laboratory and Observatory

8. From NSF EarthLab Report Induced Fracture and Deformation Processes Laboratory

9. From NSF EarthLab Report Ultradeep Life and Biogeochemistry Observatory

10. From NSF EarthLab Report Deep Coupled Processes Laboratory: study coupling among thermal, mechanical, hydrological, chemical, and biological processes in the subsurface (injection and transport experiments at several different depths along highly instrumented and well-characterized fracture/matrix zones)

11. Priority Attributes of DUSEL for Earth Science and Engineering Long-term access to large (~20+ km3) volume of subsurface in which geological features are well characterized in three dimensions, including appropriately placed sensing equipment. Ability to access this environment through selective/ choice placement of drill holes, underground workings, laboratories, or observatories. Accessed host rock should reach temperatures of 120°C and waterfilled fracture systems. Ability to modify geochemical characteristics of this environment by introduction of materials into holes or workings. At least one fracture zone should be accessed by multiple holes that are instrumented with an array of samplers for transport studies. If an existing mine is chosen as the DUSEL site, complete access to entire archive of existing data and samples.

12. EARTH SCIENCE AND ENGINEERING CRITERIA FOR DUSEL SITE Diverse chemical and physical environments, including: • Variety of hydrologic environments, such as highly permeable, near-surface soils and alluvium vs. deeper, low-permeability crystalline rocks. • Variety in groundwater compositions, such as high vs. low salinity, pH, and dissolved gas concentrations. • Variety of structural environments, especially density and orientation of faults and fractures. • Variety of geochemical environments, especially in concentration of reduced minerals (e.g., sulfides) vs. oxidized minerals (e.g., hematite).

13. Progress Made During Berkeley and Blacksburg Workshops • Starting from previous studies and workshops, the scientific community is actively working on: • Identification of Major Themes • Identify syntheses that make sense for the specialists, but also resonate with other scientists and fascinate the non-scientists • Working groups have formed for this task: Coupled processes, rock mechanics and tectonics, geo-microbiology and applications • Prioritization • What are the most pressing questions to answer deep underground?

14. Progress Made During Berkeley and Blacksburg Workshops • Some Major Themes: • Conditions for Life • Limits • Metabolism/ Energy source • Evolution • The “Ever Changing Earth” • Behavior of rock and fluids at depth. • Coupled processes in inhomogeneous media: mass, momentum,energy flow • Spatial and temporal scaling “laws” • The structure and the evolution of the earth • Observing from inside out: Core/mantle/crust/mountain • Dynamics: earthquakes • The concentration of ore deposits • Climate change • Paleo-climate ? Ancient sequestered water • Clouds “Ever Changing Earth” Dynamic, Coupled processes “Transparent Earth” : Resources Origin & Discovery Conditions for Life

15. Progress Made During Berkeley and Blacksburg Workshops One Approach: Evaluate DUSEL in different contexts An “Observatory” An “Active Processes Laboratory”

16. Progress Made During Berkeley and Blacksburg Workshops As an “observatory,” some major science questions include: 1. What are the limits of conditions for microbial life? 2. Can we increase our fundamental knowledge of the earth and its dynamic processes? Observe Earth from the inside… 3. Can we improve resolution, using observations at multiple-scales and at ranges of depths, of the couplings among thermal, hydrologic, chemical and mechanical (deformation) processes? (natural observatory context)

17. Progress Made During Berkeley and Blacksburg Workshops As an “active laboratory,” some major science questions include: How do Mass, Momentum, and Energy transfer and transform in fractured media? (carry out THMCB Experiments) 2. How may we image and scale in fractured media? How may we engineer ultra-deep and large excavations? How may we better understand cloud processes to improve climate prediction? • Examples • Ore formation, characterization and recovery • Heat extraction (geothermal reservoirs) • Fracture and fault deformation and flow • Mineral precipitation and dissolution

18. Progress Made During Berkeley and Blacksburg Workshops Experiment Requirements and Infrastructure Matrix

19. Example: Drift Scale Test at Yucca Mountain • Purpose of the test is to evaluate coupled thermal, hydrological, mechanical and chemical processes surrounding the potential repository • Dimensions: ~ 50 meters long by 5 meters in diameter • Electric heaters activated Dec. 1997, turned off Jan. 2002 • Maximum drift wall temperature reached ~ 200°C • Water, gas, and rock samples collected from boreholes for geochemical and isotopic studies • Reaction-transport modeling performed prior to and during test (examples on following slides)

20. Water-Gas-Rock and Fracture-Matrix Interaction of Heat and Mass • Water-Gas-Rock Interaction: • Mineral dissolution and precipitation • Changes in fluid chemistry as a result of transport/mixing, boiling/evaporation, mineral-water-gas reactions • Reaction rates in fractures related to wetted surface area • Fracture-Matrix Interaction: • Advection and diffusion across fracture-matrix interface • Also related to wetted surface area

21. Measured and Modeled CO2 Over Time

22. Calcite Precipitation-Dissolutionand 14C Evolution Calcite precipitation in fractures above heaters owing to boiling of water draining in fractures (reflux zone) • Calcite dissolution occurs in drainage and condensation zones • 14C strongly lowered in CO2 due to calcite dissolution and addition of “dead carbon”

23. Considerations for Boulder Workshop • De • Define rationale and requirements for depth - • Pressure, temperature, stress, chemistry • Plot showing depth-property ranges for • experiments comparable to plots shown for • physics experiments • Define rationale and requirements for rock • type and characteristics • Infrastructure needs for experiments