(Table 1) Remanence properties of samples from ODP Core 126-792A-7H

A combination of high sedimentation rates and high concentrations of magnetic grains in cores from Ocean Drilling Program Leg 126 resulted in the recovery of detailed direction and intensity records of the Brunhes/Matuyama geomagnetic polarity reversal. Virtual geomagnetic poles (VGPs) computed from...

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Bibliographic Details
Main Authors: Cisowski, Stanley M, Koyama, Masato
Format: Dataset
Language:English
Published: PANGAEA 1992
Subjects:
126-792A
ARM
Intensity
per unit volume
Demagnetization level
DRILL
Drilling/drill rig
DSDP/ODP/IODP sample designation
IRM
Joides Resolution
Leg126
North Pacific Ocean
NRM
Intensity after demagnetization
Median destructive field/ARM
Median destructive field ratio
Median destructive field/IRM
Ocean Drilling Program
ODP
Sample code/label
Type
Virtual geomagnetic pole latitude
Virtual geomagnetic pole longitude
Low Point
Pacific
Geomagnetic Pole
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.773510
https://doi.org/10.1594/PANGAEA.773510
Description
Summary:A combination of high sedimentation rates and high concentrations of magnetic grains in cores from Ocean Drilling Program Leg 126 resulted in the recovery of detailed direction and intensity records of the Brunhes/Matuyama geomagnetic polarity reversal. Virtual geomagnetic poles (VGPs) computed from azimuthally oriented samples taken from the cores of Hole 792A in the western Izu-Bonin forearc basin reveal that the geomagnetic pole persisted at moderate to high southern latitudes for several thousand years before a rapid migration to northern latitudes. Alternating-field demagnetization behavior, as well as NRM, NRM/ARM, and NRM/IRM intensities for samples from this same interval, and the NRM/IRM intensities derived from unoriented core samples from Holes 790C and 791B, drilled in the ~100-km distant Sumisu Rift, all suggest that the dipole field oscillated widely in intensity before the reversal. The fast polarity change occurred at the low point of an ~1100-yr field intensity cycle. This "reversal cycle" immediately followed earlier intensity cycles whose peaks rivaled or surpassed the normalized intensities of discrete samples from well above and below the reversal interval; furthermore, the troughs indicate a much diminished dipole field at their nadir.

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