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Oregon Geology

Abert Rim

Discovered by Captian John C. Fremont
December 20, 1843, and named
in honor of Colonel J. J. Abert.

Abert Rim, some 2500 feet above
the valley floor is one of the
hghest fault scarps in the
United States. This basalt formation,
a basic lava covering much
of eastern Oregon, issued from
great fissures during the Miocene
period of geologic history many
millions of years ago. After this
extensive lava flooding, the earth's
crust was fractured at many points
and great blocks were tilted. Abert
Rim is the western edge of one of
these tilted blocks while Abert
Lake lies on top of another.

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