Transcript Imaging Geothermal Hydrofracturing

Session Dinner
Zur Alten Kaisermühle Restaurant,
Alte Donau, Fischerstrand 21A
7.45 pm tonight
Payment: Cash at the restaurant
(no credit cards)
Meeting point:
We will set off for the restaurant at 7.15 pm
from this room (24)
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Challenges to Plume and Plate –
Telling it like it is
Gillian R. Foulger
University of Durham, UK
Definition of a “plume”
• Definition of
“plume”
• Composition
• Volume
• Temperature
• Seismology
• Summary
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fossil plume (Rotolo et al., 2006)
dying plume (Davaille & Vatteville, 2005)
recycled plume head (Gasperini et al., 2000)
tabular plume (Hoernle et al., 1995)
finger-like plume (Cadoux et al., 2007)
baby plume (Ritter, 2006)
channelled plume (Oyarzun et al, 1997)
toroidal plume (Mahoney et al., 1992)
head-free plume (Ritter, 2006)
cold plume (Hanguita & Hernan, 2000)
depleted residual plume (Danyushevsky et al., 1995)
pulsating plume (Krienitz et al., 2007)
subduction fluid-fluxed refractory plume (Falloon et
al., 2007)
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Comparison with geosynclines
• Definition of
“plume”
• Composition
• Volume
• Temperature
• Seismology
• Summary
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Mio-geosyncline
Eu-geosyncline
Ortho-geosyncline
Primary geosyncline
Zeugo-geosyncline
Para-geosyncline
Exo-geosyncline
Taphro-geosyncline
Paralia-geosyncline
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Basic observations
• Definition of
“plume”
• Composition
• Volume
• Temperature
• Seismology
Large amounts of compositionally
distinct magma
• Summary
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Composition
• Definition of
“plume”
• Composition
• Volume
• Temperature
• Seismology
The bottom line:
Geochemistry (FOZO, C, PHEM
etc.) does NOT require a lowermantle source
• Summary
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Volume
• Definition of
“plume”
• Composition
The primary observable
• Volume
• Temperature
• Seismology
• Summary
But it often cannot be explained –
by plumes, or other mechanisms
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Volume
• Definition of
“plume”
• Composition
• Volume
• Temperature
• Seismology
• Summary
Cordery et al. (1997)
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Volume
• Definition of
“plume”
• Composition
• Volume
• Temperature
• Seismology
• Summary
Van Wijk, 2001
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Temperature
• Definition of
“plume”
Are “hot spots” hot?
• Composition
• Volume
• Temperature
What evidence is there for high T?
• Seismology
• Summary
Petrology?
Seismology?
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Temperature
• Definition of
“plume”
• Composition
• Volume
• Temperature
• Seismology
• Summary
Herzberg et al., 2007 11
Temperature
• Definition of
“plume”
• Composition
• Volume
• Temperature
• Seismology
• Summary
Korenaga, 2004
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Seismic tomography
• Definition of
“plume”
How can it help us?
Can it help us?
• Composition
• Volume
• Temperature
• Seismology
• Summary
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Major problems:
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Repeatability poor
Poor data coverage globally
Interpretation ambiguous
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Seismology
• Definition of
“plume”
• Composition
• Volume
• Temperature
• Seismology
• Summary
Comment of van der Hilst & de Hoop (2005) on “plumes”
identified by “banana-doughnut tomography”
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Seismology
• Definition of
“plume”
• Composition
• Volume
• Temperature
• Seismology
• Summary
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Velocity dependent on:
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Phase (mineral or state)
Composition
Temperature
RED
= HOT
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Summary
• Definition of
“plume”
• Composition
The bottom line:
• Volume
• Temperature
• Seismology
• Summary
Fundamental problems to address
Lots of methods available
But serious difficulties that should not be
ignored
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That’s all folks