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This presentation will feature some of the geologic highlights that have made the San Diego region the great place that it is for hiking and all sorts of outdoors activities. Prior to about 200 million years this area was occupied by seafloor and the space was gradually filled in by giant intrusions of granitic rocks capped by volcanoes. By five million years ago, a series of faults became the San Andreas fault system Baja California pulled away from mainland Mexico and the Gulf of California and Imperial Valley began forming. Several million years ago a branch of the San Andreas, our Rose Canyon fault, became active and pulled Point Loma away to form San Diego harbor.
The presenter is Monte Marshall, a fourth generation San Diegan with a Stanford PhD, in Geology and Geophysics..He worked for the United States Geological Survey and then began teaching and research in the SDSU Dept. of Geological Sciences. His main research projects have been using paleomagnetism to measure plate motions in Southern California, and gravity studies of the faults of metropolitan San Diego and the western Imperial Valley.