Pasadena orogeny and Ventura Basin are consequences of the Pasadena orogeny. The city of Long Beach, California lies within the affected region. Pasadena orogeny Pasadena orogeny is a mountain building event. Conventionally it refers to the formation of mountains in mainly Southern California during the Pleistocene and lasting until the present day; originally it referred to the uplift of the San Gabriel Mountains. The Pasadena orogeny is a major Late Quaternary-modern event of mountain formation, which took place in the middle or perhaps late Pleistocene or to the present-day. It is also known as the "Coast Ranges orogeny" or considered to be
Grenville orogeny here. Ages are approximated from the magmatic activity associated with the individual cycles of the orogeny. The gaps in the ages of the compression cycles and isotope analysis of hornblende, biotite, and potassium feldspar suggest that extension was occurring when compression had momentarily ceased. Rivers' 2008 paper has now examined the timing of the different periods of the orogeny and reconstructed the timeline based on the spatial and temporal metamorphism of the rocks present. According to this newer version of the timeline which is a composite of Rivers 1997 and Gower and Krogh 2002, the Elzevirian orogeny occurs from 1240