Basin & Range / Mojave Desert Basin & Range vs. Great Basin 1
2/20/2016 An overview of the last horst Basin and Range / Mojave Desert Summary: Granitic, volcanic, marine sedimentary, non marine sedimentary, metamorphic Horst and Graben structure, fault block mountains. A recent geologic event Great Basin is part of this province The Basin and Range extends into Nevada, Arizona, northern New Mexico, western Utah and southern Idaho Has very old and very young rocks 2
The Colorado Plateau 130,000 square miles (337,000 square km) Bryce Canyon National Park 3
2/20/2016 The Wave, a sandstone formation located on the Colorado Plateau in the Vermilion Cliffs Wilderness Area, near the Arizona-Utah border. The Great Unconformity within the Grand Canyon's Inner Gorge The time gap within the contact is 1.2 billion years, more time than it took to form all of the canyon's layers. Grand Canyon National Park Zion National Park Colorado Plateau Summary: Mostly marine sedimentary and volcanic rock some igneous and metamorphic rock A high standing crustal block of relatively undeformed rocks, dissected by long north south faults Consists of broad open folds, volcanic features and consolidated sedimentary rock Approximately 5 million years ago the entire Rocky Mountains and Colorado Plateau were uplifted 4,000 to 6,000 feet. The Salton Trough 4
2/20/2016 North American Western Plate Boundary Oligocene to Present Mud pots gurgle and bubble, a sign of the geological activity going on underneath. These mud volcanoes and pots are located in the Brawley Seismic Zone, an area 25 miles long that extends from Brawley through Calipatria up to Bombay Beach. 162 mi. Water from the Pacific ocean flowed into the rift valley, creating what is now the Gulf of California Northern tip begins the Salton Trough 5
2/20/2016 Salton Trough Summary: Mostly non marine sedimentary and volcanic rock at surface, marine sedimentary below A structural basin, a continental rift, the northern extension of the Gulf of CA Basin is filled with over 5 Kilometers of marine and non marine sediment Fault scarps and rifts, high heat flow, seismic and volcanic activity common Old Shoreline of Lake Cahuilla, Santa Rosa Mountains near the Salton Sea Transverse Ranges 6
Basins and Valleys Santa Clara River 116 miles long Watershed is ~1,600 square miles Maximum annual streamflow ~109 cubic meters per year and ~100 million tons of sediment deposited in Santa Barbara Channel The Transverse Ranges can be divided into three main regions that share similar geologic characteristics: -Western Transverse Ranges Santa Ynez Mountains, Mountains of Central Ventura County -Central Transverse Ranges San Gabriel Mountains, Santa Monica Mountains, Channel Islands, Los Angeles Basin -Eastern Transverse Ranges San Bernadino Mountains and Little San Bernadino Mountains 7
Peninsular Range Satellite Image showing airflow patterns of the Santa Ana Winds in Coastal Southern California map Satellite Image showing the Santa Ana Winds and their contribution to the spreading of wildfires in Southern Coastal California San Jacinto & Elsinore Faults Transverse Ranges Summary: CHANNEL ISLANDS Only province with NE / SW structural trend All rock types common Rotated ~90 degrees clockwise from Miocene to present Very old and young rocks, individual mountain ranges have complex geologic histories 8
The Peninsular Range Peninsular Range extends 880 miles south into Baja California Peninsular Range Summary: Over 140 miles long in CA, but continues to 750 miles to south Granitic Rocks and Marine Sedimentary Rocks dominate San Jacinto Fault and the Elsinore Fault are the dominating structural features Overall geologic history similar to the Sierra Nevada Southern Baja California Batholith 9
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