Pasadena orogeny 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 part of the Cascadian orogeny or Alpide Orogeny. Finally, the term "Pasadena orogeny" is sometimes applied to all very recent
Grenville orogeny of Laurentia, and likely collided with a different continent than that involved in the eastern collision. The Zapotecan Orogeny of Mexico is coeval with the later stages of the Grenville orogeny, and they are generally considered to be one and the same. Mesoproterozoic igneous protoliths (metamorphosed to granulite facies during the orogeny) fall into two age groups in Mexico; c. 1235–1115 Ma and c. 1035–1010 Ma. Rocks of the former group bear geochemical signatures implying island arc and back-arc basin provenance. The latter group represents AMCG magmatism. These AMCG rocks are somewhat anomalous throughout the Grenville orogen, there is no