Open AccessPalaeomagnetism of the Pico Formation, Santa Paula Creek, Ventura Basin, California
Author(s) -
Liddicoat Joseph C.
Publication year - 1992
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1992.tb00872.x
Subject(s) - paleomagnetism , clockwise , polarity (international relations) , geology , structural basin , paleontology , rotation (mathematics) , tectonics , turbidite , polarity reversal , geomorphology , geometry , physics , chemistry , mathematics , voltage , quantum mechanics , cell , biochemistry
SUMMARY In the western Ventura Basin in southern California, marine turbidites in the Pico Formation are exposed along Santa Paula Creek in a southeast‐dipping homocline. The section is about 3 km thick and contains normal and reverse polarity that was acquired before the development of the homocline. Although the sediment contains a secondary component of normal polarity that cannot be removed entirely by thermal or alternating‐field demagnetization, the mean declination for 26 sites (12 normal polarity, 14 reverse polarity) shows a clockwise rotation of 19.8d̀± 9.0d̀ that is similar to the rotation recorded in the Saugus Formation, a coeval, non‐marine deposit in the eastern Ventura Basin that was studied by Levi et al . (1986). The partial overprint of the secondary component of normal polarity results in a mean inclination for each polarity that does not match the inclination of an axial dipole field (the inclination is too steep in normal polarity and too shallow in reverse polarity); still, the inclination for the combined sites is close to the expected inclination (52.0d̀ versus 53.9d̀). Overall, turbidites in the Pico Formation are suitable for a magnetostratigraphic investigation, but caution is required if the palaeomagnetic data are to be used in a tectonic study.