Transcript Roggenthen_EarthLabPierreshort

Geosciences in an
Underground Laboratory:
EarthLab
W. M. Roggenthen
SD School of Mines & Technology
EarthLab:
A Subterranean Laboratory and
Observatory to Study Microbial Life,
Fluid Flow, and Rock Deformation
Brian McPherson, New Mexico Institute of Mining and Technology
Derek Elsworth, Pennsylvania State University
Charles Fairhurst, University of Minnesota
Stephen Kesler, University of Michigan
Tullis Onstott, Princeton University
http://www.earthlab.org
William Roggenthen, SDSMT
Herb Wang, University of Wisconsin
Requirements – what Geosciences need:
1. A large (~20+ km3) volume of rock with
interesting geology.
2. Drill holes and underground workings in rocks
reaching temperatures of 120°C - water-filled
fracture systems.
3. Ability to introduce materials into holes,
workings, or fractures to modify the
geochemistry of the rock.
4. Existing geologic data and samples.
Homestake Mine, Lead, SD
• EarthLab:
• A “window” into the basement of
North America
•Microbial Life at Depth
•Hydrologic Cycle
•Rock-Water Chemistry
•Rock Deformation and Fluid Flow
•Deep Seismic Observatory
Microbial
Life at
Depth
The Ultradeep Life and Biogeochemistry
Observatory
Purpose:
to search for the limits of life
•what is living at depth?
•how does it take advantage of its
environment?
•what is its metabolic rate/how does
it grow?
Methods:
use closely spaced boreholes that:
• attain depths up to 5 km
• have bottom-hole temperatures of 110120°C, the maximum known temperature for
life
Homestake Mine, Lead, SD
~16,000 ft
Hydrologic Cycle
The Deep Flow and Paleoclimate
Laboratory and Observatory
Purpose:
to search for continental paleoclimate records
and document deep transport processes
Methods:
instrument a fracture zone extending from the surface
to the maximum depth of the laboratory.
Deep Flow
Hydrologic
Experiments
will provide
information on
the movement of
groundwater in
the crust and its
relationship to
Earth’s
changing
climate.
The Induced Fracture and Deformation
Processes Laboratory
Purpose:
to conduct extensive studies of three-dimensional
rock deformation in heterogeneous rock formations
Methods:
Instruments in boreholes will measure:
•Rock deformation associated with
mining out a large cavity
•Creation of fractures using highpressure fluid
•Deformation resulting from heating
small volumes of rock
Induced
Fracture and
Deformation
Data are critical to
scaling-up models
used to predict
long-term stability
of subsurface
excavations.
The Deep Seismic Observatory
Purpose:
To make the largest and best seismometer in the world.
Method:
•The laboratory will become the instrument.
•Will use a fully three-dimensional array consisting of at
least 60 broadband seismometers in tunnels and
boreholes.
Key Numbers for EarthLab
Anticipated total tunnel length:
~ 10 km
Greatest tunnel depth:
~ 2 - 2.5 km
number of instrumented boreholes:
~ 140
total length of rock core to collect:
~ 15,000 m
Genetic materials - novel microorganisms
Analytical techniques for geomicrobiology
Environmental remediation
Subsurface imaging
Natural resource recovery