Workshop on Scientific Drilling of the Snake River Plain Sponsored by the International Continental

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Workshop on Scientific Drilling of the Snake
River Plain Sponsored by the International
Continental Drilling Program
Twin Falls, Idaho, 18-21 May 2006
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Tracking the Yellowstone HotspotThrough Space
and Time
John W. Shervais, Utah State University Michael
Branney, University of Leicester Dennis Geist,
University of Idaho Barry B. Hanan, San Diego
State University Scott S. Hughes, Idaho State
University Alexander Prokopenko, University of
South Carolina Douglas F. Williams, University
of South Carolina
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Yellowstone Plume Geoid Anomaly
Active Tectonics Smith U of Utah
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Heat Flow and Seismic Velocities
Seismic Velocity Structure Humphreys Dueker
Heat Flow
SMU Geothermal Lab
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Where Did it Start?
Glen Ponce, 2002
?
Camp Ross, 2004
Craton Margin
Glen, unpublished
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Plume Tilt
Yellowstone Plume Dip 20º NW Depth 500 km
Yuan Dueker, 2005
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Major Science Issues

• How Do Mantle Plumes Interact with Continental
  Lithosphere/Crust?
• What Does This Tell Us About Fundamental
  Processes of Continental Dynamics and Geochemical
  Evolution of the Earth?
• Baseline What We Know About Plumes From Oceanic
  Settings
• (e.g., Hawaii Deep Drilling Project)
• Tools Basalt Geochemistry as Probe of Mantle,
  Geophysics to Understand Lithosphere structure.

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Lithosphere-Asthenosphere-Plume?
N-MORB
Hawaii, SRP
Plume
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SRP coincides with Hawaii
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SRP coincides with Hawaii
MORB
?
Plume
Hawaii
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SRP-style Rhyolites

• VERY Hot 850º C -- 1000º C
• Very Large Volume Lavas and Lava-like Ignimbrites
  
• Dry melts of continental crust

Additional Science Issues
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Additional Science Issues Paleoclimate of
intra-continental North America during
Pliocene-Pleistocene Transition

• Western SRP provides complete section of lake
  sediments deposited during the Pliocene and early
  Pleistocene from extinct Lake Idaho.
• Lake Idaho sediments offer advantage that
  drilling would not involve an existing lake, and
  can be drilled with standard landbased
  technology.

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HOTSPOT Snake River Scientific Drilling
Project Twin Falls, Idaho, 18-21 May 2006
Sixty Participants Six Countries
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Keynote Topics AM

• Tectonic Overview of Snake River Plain
• SRP Rosetta stone of continental volcanism
• Geochemistry of SRP Basalts
• The Rhyolite Story
• Hawaii Scientific Drilling Project

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Keynote Topics PM

• Paleoclimate Cyclostratigraphy
• Lake Drilling in Western US
• Magnetostratigraphy
• Continental Scientific Drilling (DOSECC)
• International Continental Scientific Drilling
  Program Funding Logistics
• Downhole Geophysical Logging
• Cyberinfrastructure in the Geosciences

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Field Trip
WSRP Basalts overlie, underlie Diatom-rich
Lake Sediments
ESRP Massive Basalts
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Dutch Oven BBQ in Snake River Canyon
Where the Real Work Got Done!
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Break-Out Groups

• Basalt Geochemistry Isotopes
• Rhyolite Geochemistry Petrology
• Paleoclimate Cyclostratigraphy
• Chronostratigraphy
• Regional Borehole Geophysics
• Hydrothermal Processes Alteration

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Approach Smaller, Faster, Cheaper

• Where Possible Use existing DOSECC Drill Rigs
  (e.g., CS1500).
• Pick sites where drilling targets accessible with
  this equipment.
• Rhyolite target Deepen Existing Hole at Idaho
  National Lab.
• Far West SRP Rotary Drill to Basalt, or deepen
  existing well, side-core targets.

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Goals Basalt Drilling

• Transect of craton margin, starting in the
  accreted oceanic terranes.
• Time-Space variations in Plume-Lithosphere-Astheno
  sphere sources.
• Four New Holes Existing Holes
• Two in ESRP 1.2 km deep
• One WSRP on horst block
• One West of Craton margin (deepen existing
  wildcat hole?)

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Lithosphere Varies in Thickness, Age Composition
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Lithosphere Varies in Thickness, Age Composition
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Plume carves channel in Lithosphere
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Goals Rhyolite

• Deep Hole through Rhyolite on Axis
• Volume of rhyolite within the SRP
• Time variation of crustal melts
• Heat flux to melt crust basalt
• Deepen Existing Hole at INL
• INEL-1 3.14 km (2.4 km rhyolite)
• WO-2 1.52 km (0.36 km rhyolite)
• DOE may fund (???)

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Rhyolite Deepen Existing Hole INL
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Paleoclimate of intra-continental North America
during the Pliocene-Pleistocene Transition

• Reconstruct the late Neogene history of North
  Pacific atmospheric water transport into the
  Great Basin of western North American craton.
• Resolve linkages between North Pacific
  atmospheric water transport and the initiation of
  Northern Hemisphere glaciation.
• Examine the response of the Great Basin
  hydrological system to the Pliocene climatic
  optimum.
• Resolve a complete, high-resolution record
  (nature, timing and character) of the
  Plio-Pleistocene climatic transition in
  mid-continent North America.

Additional Science Issues
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Paleoclimate of intra-continental North America
during the Pliocene-Pleistocene Transition
Additional Science Issues

• Determine the record of explosive volcanism in
  the Snake River Plain during the Late Neogene
• Resolve Late Neogene record of biotic and
  landscape evolution in relation to tectonic
  magmatic processes related to hotspot evolution.
• Use the high resolution records afforded by
  lacustrine deposits to infer the chronology of
  biotic recovery in both terrestrial and aquatic
  ecosystems in the post-eruption intervals
  following some of the largest explosive volcanic
  eruptions known.
• Develop a master reference section for
  sediments interbedded in basalts and rhyolites to
  be drilled by HOTSPOT.

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Goals Lake Idaho Drilling

• Shallow holes (350-500 m deep) in WSRP
• Deep lake facies Horst block underlies gravity
  high.
• Shore facies uplands along northern margin of
  plain.
• Gravity High Same target as Basalt Drilling --
  use same hole for both.

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Lake Idaho Drilling Tie-in with Basalt Hole on
Gravity High
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Hydrothermal Systems-Alteration

• Magma source
• Size and shape, degree of partial melting
  estimated from thermal volatile flux.
• Requires depth profiles of thermal conductivity,
  porosity, permeability.
• Requires extensive understanding of groundwater.
  
• Effect of altered rock on magma
• Effect of altered rock on composition of magma
  (chemical, isotopic).
• Age of alteration
• Plume-associated vs. pre-plume alteration
• Deep vs. Shallow
• Deep hole necessary to get profile of properties
  and get record
• Get to unexposed materials fastest in Eastern
  Snake River Plane.
• Some more points
• Effects of post-implacement alteration on
  chemistry and isotopic composition.
• Minerals formed by alteration record chemical
  and isotopic alteration of groundwater

Additional Science Issues
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EarthScope

• Ground Truth for Big Foot array.
• Flex-array More Data on Lithosphere Structure,
  plume-lithosphere interactions.
• Drilling Complements EarthScope with View of
  Upper Crustal Response to Hotspot-Lithosphere
  interactions.
• Coupling with EarthScope will be critical to
  success.

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Pre-Drilling Activities

• Compilations of Existing Data Shared
• (project-wide database well logs, cores,
  geologic and geophysical data)
• Coordinate with EarthScope geophysical
  investigations.
• Regional geophysical framework based on existing
  data.
• Analyze/model existing data to support drill hole
  site selection.
• Acquire shallow seismic if possible...

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Next Steps

• PI Planning meeting Summer 2006
• SRP Drilling Session at AGU December 2006
• Pre-Proposal to ICDP January 2007
• Pre-Proposal to NSF June 2007
• Full Proposals to Both January 2008?