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Rapid Post‐Miocene tectonic rotation associated with the San Gregorio Fault Zone in central California
Author(s) -
Holm Eric J.,
Horns Daniel M.,
Verosub Kenneth L.
Publication year - 1991
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/91gl02760
Subject(s) - geology , clockwise , paleomagnetism , tectonics , seismology , fault (geology) , block (permutation group theory) , fault block , shear zone , shear (geology) , fold (higher order function) , paleontology , rotation (mathematics) , geometry , mathematics , mechanical engineering , engineering
Paleomagnetic measurements of samples from the Mio‐Pliocene Purisima Formation demonstrate that the Pomponio tectonic block of central coastal California has rotated clockwise by approximately 35° to 55° within the last 2.5 million years. The most likely interpretation of this data is that the Pomponio block is broken into several small blocks which have rotated by various amounts. The data suggest that rotations contribute to vertical deformation and secondary faulting within the central San Andreas Fault System, and that they play an important role in the accommodation of shear along the fault system.