GG 612 Geomag' Paleomag' Part III

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GG 612 Geomag. Paleomag. Part III
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Magnetostratigraphy.
Principles. Application. Astronomical tuning.
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Principles.
Require a recognizable pattern of reversals
Initially reversals named, but eventually a more
flexible, numerical system was adopted. Present
Chron Bruhnes - 1n Last initially Matuyama
1r, If we find another chron in 1r ,we call it
1r.1n etc.
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Principles 2
Linked to paleontological stratigraphy.
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Application Ocean Drilling Project
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Drilling system on theResolution
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Drilling
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Corer and Recovery
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Application
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Astronomic tuning
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Cyclicity in sediments
Trubi marls Sicily Grey marls are insolation
maxima White-beige-white minima
Ptolemais Basin Greece Marls are insolation
maxima Correlate with grey marls in Sicily
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Astronomic tuning of Sediment record to del
oxygen record.
In this case by susceptibility.
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Applications of Astronomic tuning has
revolutionized stratigraphy.
Sediments can be correlated to a few thousand
years. This allows us to build up geomagnetic
field history with this same resolution. Limitat
ions for the present about 25 Myrs
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SEAFLOOR SPREADING PLATE TECTONICS
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Europe/NAmerica
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Plate Tectonic Elements
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Plate tectonic world
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Euler Poles
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Relation between Apparent Polar Wander Curves and
Plate Motion
APW paths for different plates can be combined,
if relative motion known.
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Absolute Motion the Hotspot motion controversy

• Africa APW compiled from APW for several plates,
• b) Africa APW in hotpsot frame and (c ) True
  polar wander (?)