My view of how the Tucson Basin came to be

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Frist let me say that we are not geologists. This was simply our way of understanding better what we have read in various reports.
The animation starts during late Jurassic Time when a valcano located north of present day Tucson began to erupt. This valcano eventually exploded in a Mt. St. Helens fashoin and a caldera was formed. The batholith underneath began to cool and harden into granite. The batholith was then pushed up by plate techtonics approximately 8 miles from its original location. A normal fault occured, and the top of the old valcano slid down the side of the rising batholith. More valcanos erupt to the west of present day tucson. The old caldera slides along the glide fault and eventually ends up in the middle of the valcanoes which are in turn intruded by a batholith that forms Wasson Peak. More faulting breaks the original caldera into the large fault blocks of Cat Mountain seen today. The plates finally move past eachother, and crustal stretching starts to form the Tucson Basin into which debris are washed from the surrounding mountians.
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