Mathematics – Logic
Scientific paper
Jun 1982
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1982e%26psl..59..192e&link_type=abstract
Earth and Planetary Science Letters, Volume 59, Issue 1, p. 192-207.
Mathematics
Logic
3
Scientific paper
A magnetic polarity zonation has been established for the upper Castaic Formation and lower Ridge Route and Peace Valley Formations of the Ridge Basin of the central Transverse Ranges of southern California. The zonation is based on the analysis of over 1900 samples from 669 sites in the 5800 m thick sedimentary sequence. Rock magnetic studies provide evidence that the carrier of the primary remanence is magnetite and that the magnetization was acquired at or shortly after deposition of the sediment. Although many samples contain a secondary, normal overprint, systematic analysis of the changes in direction upon demagnetization leads to an accurate determination of the original polarity. Thirteen polarity intervals are recognized. On the basis of biostratigraphic constraints imposed by a marine invertebrate fauna at the base of the sequence and a terrestrial vertebrate fauna at the top, the magnetic polarity zonation can be correlated to the magnetic polarity time scale. The studied interval extends from the Epoch 5/Epoch 6 boundary to the middle of Epoch 8.
Polarity changes within the studied interval represent chronostratigraphic horizons which can be used to analyze tectonic and sedimentologic processes which are recorded in the sediments of the Ridge Basin. The locus of the tectonic activity within the basin has been dated as occurring on the Clearwater fault from 8.1 to 7.8 m.y. ago, on the Liebre fault from 7.3 to 6.1 m.y. ago and on the North Liebre fault from 6.0 to 5.0 m.y. ago. During this entire period of time, the San Gabriel fault on the western margin of the basin was continuously active, and a period of particularly vigorous activity has been dated at 7.3 to 7.0 m.y. The mean declinations of samples from the normal magnetozones provide no evidence for the existence of a major rotation of the Ridge Basin subsequent to about 8.5 m.y. ago. Sedimentation rates for interbedded sandstone and shale units within the basin have been separately determined as 0.2 m/1000 years and 3.0 m/1000 years, respectively. The water content of certain deformed structures within the sequence has been determined to have been 35% and 40% at the time of deformation.
Ensley Ross A.
Verosub Kenneth L.
No associations
LandOfFree
A magnetostratigraphic study of the sediments of the Ridge Basin, southern California and its tectonic and sedimentologic implications does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A magnetostratigraphic study of the sediments of the Ridge Basin, southern California and its tectonic and sedimentologic implications, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A magnetostratigraphic study of the sediments of the Ridge Basin, southern California and its tectonic and sedimentologic implications will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1353213