Accession Number:

AD0608936

Title:

PALEOMAGNETISM OF THE MIOCENE LAVAS OF SOUTHEASTERN OREGON.

Descriptive Note:

Final rept., part 2,

Corporate Author:

STANFORD UNIV CALIF

Personal Author(s):

Report Date:

1964-04-01

Pagination or Media Count:

88.0

Abstract:

Magnetic properties of ten widely separated sections of Miocene lavas in Oregon were studied. The results support the following conclusions 1 Secular variation of the geomagnetic field during part of the Miocene period has an amplitude similar to secular variations observed at present. 2 Using conventional assumptions, an earlier suggestion that the spin axis was apparently slightly removed from its present position during the Miocene period is supported. A previous suggestion that the geomagnetic pole reached its present position by the Miocene period is not supported. 3 PostMiocene differential tectonic rotation cannot explain the relative orientations of the mean directions of natural remanent magnetism in sections featuring dual distributions. Large scale post-Miocene differential tectonic rotation about vertical axes in the area seems unlikely. 4 When integrated with the results from other presently available studies of Miocene paleomagnetism, an apparent rapid movement of the ambient geomagnetic field must be attributed to an increase in the relative contribution of the non-dipole component to the total Miocene geomagnetic field. This conclusion may be modified with an increase in data from Miocene rocks in other areas. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE