Electronic Resource
Oxford, UK
:
Blackwell Publishing Ltd
Geophysical journal international
7 (1955), S. 0
ISSN:
1365-246X
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Geosciences
Notes:
The directions of remanent magnetization of samples taken from a number of varved clay series from Sweden have been measured in an attempt to obtain information about the direction of the Earth's field in past times. Two sets of samples were taken with a Kullenberg core sampler from cores of recent varves obtained from a river delta. It was possible therefore to compare the magnetization directions of these samples with observatory records of the Earth's field direction at the time of deposition of the clay. The results indicate that the magnetizations were acquired on deposition and have remained stable in direction since. Their directions are shown to have been controlled not only by the Earth's field but by the slope of the bed on which deposition took place and very probably by bottom currents flowing in the river or lake during sedimentation. Thus no information about the past direction of the Earth's field can be obtained from the data unless corrections can be applied to allow for these factors. A method of correcting approximately for the change of magnetization direction due to deposition on a slope is explained. No way of allowing for the effects of bottom currents has yet been discovered, though there is evidence that in some instances these effects are small. Where this is so the magnetization direction may perhaps prove a reliable indicator of the field direction at the time of deposition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-246X.1955.tb06557.x
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