Tectonic History of Western North America and Southern California - A1

High quality: http://www.youtube.com/watch?v=G2_1dqgai10&fmt=18

An Animated Tectonic History of Western North America and Southern California.
Tanya Atwater, Dept. Geological Sciences, University of California, Santa Barbara, CA

Summary list of QuickTime animations:

A.Pacific-North America Plate Tectonic History (map views)
1. Pacific Hemisphere, 80 Ma to Present
2. N.E. Pacific and W. North America, 38 Ma to Present
3. California, 20 Ma to Present
4. Southern California, 20 Ma to Present
5. Southern California Paleomagnetic Vectors
6. Southern California, Origin and Dispersal of the Poway Conglomerate

B.Geologic History of the Transverse Ranges, Southern California
1. Mesozoic Subduction
2. Miocene: Rifting and rotation, volcanism and deposition in marine basins
3. Plio-Pleistocene: Oblique Shortening against the "Big Bend"
4. Santa Barbara Channel Oil

A.1. Pacific Hemisphere Plate Tectonic History, 80 Ma to Present (stable North America held fixed).
Drawn and animated by Tanya Atwater using PhotoShop and Morph.
Images modified after original reconstructions downloaded from
www.odsn.de/odsn/services/paleomap/paleomap.html
Present Situation.
At present the Pacific Plate fills most of the north Pacific Ocean basin. The various shades of blue show the ages of the sea floor, as deduced from marine magnetic anomalies. The Pacific plate is moving northwest toward the subduction zones of the Aleutians and the western Pacific island arcs. Along the rim of North America, it has captured some slivers of the continental edge and is carrying them northwestward toward Alaska. Thus, the present Pacific-North America plate boundary lies within the continent, along the San Andreas and Queen Charlotte fault systems. This was not always the case......
Late Cretaceous Situation, 80 Ma.
In the late Cretaceous, 80 million years ago, there were several oceanic plates within the Pacific basin: the Pacific plate was a smallish southern plate with the Aluk, Farallon, and Kula plates spreading away from it.
• Oceanic Plate Evolution. Coming forward in time, the Pacific plate drifted north and it grew and grew until it came to fill most of the north Pacific.
• East Pacific Rise Migration. Now watch the eastern edge of the Pacific plate. This is the sea floor spreading center called the East Pacific Rise. It moved steadily northeastward as it accreted new sea floor onto the edge by sea floor spreading between the Pacific and Farallon plates.
• Massive Subduction. This time watch and be impressed by the subduction; an astonishingly huge area of oceanic plate was subducted beneath North America. The Mesozoic and Cenozoic rocks of western North America are primarily a record of plate convergence in all its forms. The San Andreas fault is a very late complication superimposed on this rich history of subduction.
• Farallon Plate Disintegration. Now watch the demise of the mighty Farallon plate. 80 million years ago it was huge! It subducted beneath the Americas faster than it was being formed. As its surface area decreased, it broke into smaller plates then some of those were entirely subducted, allowing a new boundary, the San Andreas, to form between the
Pacific and North American plates.
• Pacific Plate Motion. This time watch the motion of the Pacific plate, itself. It drifted northward, then northwestward the whole time, toward the subduction zones of Japan and the Aleutian Islands. When it grew so wide that its edge came in contact with North America, it broke off continental slivers and carried them away to the northwest.

Category:

Science & Technology

Tags:

• Tanya Atwater
• geology
• plate
• tectonics
• paleomagnetism
• baja
• california
• santa barbara
• pacific
• north
• northern
• america
• Farallon plate
• pacific plate
• north american plate
• triple junction
• Juan de Fuca plate

[seyoumeye]

All these mass movements without any notable volume increases of the planet?

[britoca]

@seyoumeye subduction

[frozenstrawbs]

bomb

[tenderpetals]

Our continent is a pretty stubborn land mass. Great imagery.

[phdhbtdsmmm]

Absolutely stunning!