Modeling Magnetic Anomalies

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Modeling Magnetic Anomalies

• Ashlee Henig
• Irma O. Caraballo Álvarez

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Geomagnetic Polarity Timescale and the
Vine-Matthews Hypothesis
Figure 1. Relationship between sea-floor
spreading and geomagnetic polarity timescale.
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Generating Magnetic Anomaly Profiles
Figure 2-3. Sea SPY Magnetometer.
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Generating Magnetic Anomaly Profiles
Figure 4. Towed magnetometer.
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Generating Magnetic Anomaly Profiles
Figure 5. International Geomagnetic Reference
Field.
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Generating Magnetic Anomaly Profiles
Figure 6. Eltanin 19 EPR magnetic anomaly
profiles. Adapted from Pitman and Heirtzler,
1966.
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Generating Magnetic Anomaly Profiles
Figure 7. Pacific - Juan de Fuca magnetic
lineations. From http//pangea.stanford.edu/cour
ses/gp025/webbook/images/08J.vine.jpg
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Skewness
Figure 8. Geocentric dipole field from Tauxe
(1998).
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Skewness
Figure 9. Anomalies from local field vectors
along a line at the sea surface.
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Skewness
Figure 10. Magnetic anomaly from E-W ridge at
the equator.
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Skewness
Figure 11. Magnetic anomaly from N-S ridge at
the equator.
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Skewness
Figure 12. Skewed magnetic anomaly at low
latitudes.
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Skewness
Figure 13. Skewness of magnetic anomalies at
varying latitudes.
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Skewness
Figure 14. Edge effects.
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Anomaly Resolution
Figure 15. Fast vs. slow spreaders.
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Formula

• A(k) C2pke-2pkz ei?sgnkp(k)
• Derivative
• Upward continuation
• Skewness
• FT of magnetic reversal timescale

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Modeling Magnetic Anomalies
Figure 16. Magnetic timescale.
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Modeling Magnetic Anomalies
Figure 17. Mirrored magnetic timescale.
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Modeling Pacific Magnetic Anomalies
Figure 18. Pacific-Eltanin profile.
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Modeling Pacific Magnetic Anomalies
Figure 19. Pacific-Eltanin synthetic profile. z
3000m, v 52000m/my (vc 47967m/my), ?
-20, C 6 x 106
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Modeling Pacific Magnetic Anomalies
Figure 20. Pacific-Eltanin superimposed profiles.
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Modeling Pacific Magnetic Anomalies
Figure 21. Pacific-Eltanin zoomed superimposed
profiles.
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Modeling Pacific Magnetic Anomalies
Figure 22. Pacific-NBP profile.
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Modeling Pacific Magnetic Anomalies
Figure 23. Pacific-NBP synthetic profile. z
3000m, v 47500m/my (vc 48120m/my), ? 5, C
3 x 106
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Modeling Pacific Magnetic Anomalies
Figure 24. Pacific-NBP superimposed profiles.
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Modeling Pacific Magnetic Anomalies
Figure 25. Pacific-NBP superimposed profiles.
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Modeling Atlantic Magnetic Anomalies
Figure 26. Atlantic profile.
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Modeling Atlantic Magnetic Anomalies
Figure 27. Atlantic synthetic profile. z
4000m, v 17000m/my (vc 13510m/my), ? 55, C
1 x 106
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Modeling Atlantic Magnetic Anomalies
Figure 28. Atlantic superimposed profiles.
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Modeling Atlantic Magnetic Anomalies
Figure 29. Zoom of Atlantic superimposed
profiles.