Geomorphology
Abert Rim may be the largest exposed geological fault in North America.
Formed when a great block of basalt rock tilted to the east, it rises steeply
to a height of 2000 feet on the west side. One of the largest lakes in Oregon,
with no outlet, water can only leave by evaporation. As a result, sodium
carbonates and other salts become concentrated in the lake's waters. Note
image of white rock showing effects of alkalinity. The shore line image
above of white is a field of such rocks. Abert Rim strectches 30 miles north
to south. Lake Abert normally covers 60 square miles however the lake varies
in size from year to year depending upon precipitation. It went almost completely
dry 140 years ago. Elevation is 6,250 feet.
Wildlife
Abert Rim, stretching from the south end of Lake Abert to Alkali Lake, is
the best area to view bighorn sheep. One of the most popular spots is above
the geologic point of interest sign near mile marker 81. Bighorn sheep were
transplanted to the rim in 1975 and 1977 from nearby Hart Mountain. At the
shoreline numerous western snowy plover, one of the largest breeding populations
of such species in the world, are easily seen swiming in small three inch
circles, stiring up the brine shrimp, for a steady diet in this salty habitat.
Also watch for raptors, such as ferruginous hawk, soaring above the lake.
See the Oregon Wildlife Viewing Guide (1994) for important
additional details on wildlife description, viewing information, and directions
to wildlife viewing sites.
Sources
Watchable Wildlife: Oregon/Washington , n.d., BLM. US Department
of the Interior, Washington,D.C. .
ExplOregon , CD-ROM, 1995. University of Oregon, Departments
of Geography and Fine and Applied Arts.
Yuskavitch, J., Oregon Wildlife Viewing Guide , 1994. Falcon
Press, Helena, Montana.
Copyright
Phil Kessinger, 1997
Eugene,Oregon USA
All Rights Reserved
phil_k
at
efn.org
Revised December 2002