Joshua Tree National Park. Free-standing boulders* shape a cobbled, baren landscape. By summer, unbearably hot; by winter, only survivable next to a roaring campfire.
*The boulder rock (monzo-granite) was formed ~45 million years ago during the Mesozoic as the oceanic Farallon plate subducted under the continental North American plate, creating giant magmatic bodies called plutons that, as they cooled, developed planes of weakness on both vertical and horizontal axes. As groundwater percolated down through the plutons over time, the rock was weakened along these joints; by the time the rock was uplifted and exposed, it had already been eroded into unattached boulders - hence the dramatic landscape of free-standing boulders in Joshua Tree (and elsewhere in CA).
*The boulder rock (monzo-granite) was formed ~45 million years ago during the Mesozoic as the oceanic Farallon plate subducted under the continental North American plate, creating giant magmatic bodies called plutons that, as they cooled, developed planes of weakness on both vertical and horizontal axes. As groundwater percolated down through the plutons over time, the rock was weakened along these joints; by the time the rock was uplifted and exposed, it had already been eroded into unattached boulders - hence the dramatic landscape of free-standing boulders in Joshua Tree (and elsewhere in CA).
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