In the latest Pre-Cambrian, North America rifted away from another continent (probably E. Antarctica, part of the supercontinent Rhodinia). This left a passive margin along western North America upon which a deep stack of Paleozoic sedimentary rocks was deposited. Today, these sediments dominate the landscapes of Grand Canyon, Death Valley and the White Mountains. North America drifted across the ancient Pacific, collided to form the super-continent Pangaea, rested for 50 million years, then broke away again in the Jurassic. Tectonic events during this time span include various terrain collisions which deformed the sedimentary stack and then, post-Pangaea, a long period of subduction which further deformed and uplifted the sediments and intruded them with granites.
During the late Cenozoic, the San Andreas system and the Basin and Range extensional system, broke up the landscape, causing further deformation in the White Mountains, including presently ongoing uplift. A particularly interesting aspect of the White Mountains is that the botany very closely mirrors the rock types, so that the ancient bristlecone pines almost exclusively occupy outcrops of the Reed dolomite, etc. Atwater will lay out this history using maps, crossections, landscapes, and animations.
Tanya Atwater is an Emeritus Professor of Tectonics at the U. C. Santa Barbara. She received her education at the M.I.T., U.C. Berkeley, and Scripps Institute of Oceanography, completing her PhD in 1972. Dr. Atwater's research has concerned various aspects of tectonics, ranging from the fine details of sea floor spreading processes to the global implications of plate tectonics. She is especially well known for her works on the history of western North America and the San Andreas fault system. Dr. Atwater is devoted to science communication, presenting numerous lectures, workshops and field trips for K-12 teachers and for public groups, and consulting for museums, movie producers, and the written media. She has created a number of geological animations that are extensively used in geo-education.
Atwater's honors include the G.S.A. Cordilleran Sectionís Best Paper Award, an N.S.F.
Directorís Award for Distinguished Teaching Scholars, and Germanyís Leopold von Buch Medal for "outstanding career contributions in the geosciences". She was elected to the National Academy of Sciences in 1997.
To access Dr. Atwater's animations (free to use for educational purposes) go to http://
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