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Cenozoic -The development of the Earth as we know it today • At only 66 million years long, – the Cenozoic is only 1.4% of all geologic time Age of Ocean Basins Is Well Constrained The Circum-Pacific Orogenic Belt Geological Provinces of the U.S The North American Cordillera • The North American Cordillera is one large segment of the circum-Pacific orogenic belt extending from Alaska to central Mexico • In the United States it widens to 1200 km, stretching east-west from the eastern flank of the Rocky Mountains to the Pacific Ocean Cordilleran Mobile Belt Antler Orogeny in Devonian Change from Subduction • As the North American Plate overrode the Pacific–Farallon Ridge, its margin became transform faults • the San Andreas • and the Queen Charlotte – alternating with subduction zones Plate Interactions Continue http://earth.geol.ksu.edu/sgao/re search/data/seiswus/examp le1.gif The Laramide Orogeny • Most active in Late Cretaceous to Eocene • Formation of the Rockies Cascade Range • Some of the highest mountains in the Cordillera are the Cascades – California, Oregon, Washington, British Columbia • Thousands of volcanic vents are present – dozen large volcanoes – Lassen Peak in California • world's largest lava dome • Related to subduction of the Juan de Fuca plate http://www.cr.nps.gov/history/online_boo ks/resedu/resedu2a.htm Colorado Plateau Colorado Plateau – Paleozoic rocks exposed in the Grand Canyon, Arizona – Mesozoic sedimentary rocks in the Valley of the Gods, Utah The Continental Interior • A vast area called the Interior Lowlands – the Great Plains – and the Central Lowlands The Southern and Eastern Continental Margins • The Atlantic Coastal Plain and the Gulf Coastal Plain form a continuous belt from the Northeastern United States to Texas Coastal Plain Similarities • Both areas have horizontal or gently seaward-dipping strata deposited mostly on land or in shallow water them • Seaward of the coastal plains lie the continental shelf, slope and rise, which are areas of notable Mesozoic and Cenozoic deposition http://www.missgeo.com/directors %20-%20mail.htm Gulf-Coastal-Plain Deposition • Cenozoic Deposition on the Gulf Coastal Plain – Depositional provinces and surface geology Cross section showing seaward thickening O strata Global climate of the Cenozoic was controlled by plate motions, and associated changes in ocean circulation, and by glaciation in Antarcitca The Ice Volume Record for the Cenozoic • Isotope record records ocean temperature and ice volume • Eustatic record derived from seismic stratigraphic studies • When did glaciation begin? Pleistocene Fluctuations You Are Here! Northern Hemisphere Glaciation Cyclicity Closing of the Isthmus of Panama • Shut off E/W global ocean flow American plates collided ~ 3.5 Ma This may have resulted in glaciation in the northern hemisphere Caribbean warms Gulf Stream moves warm water north Increases ocean evaporation and precipitation on land The Last Glacial Maximum