Diamond Craters
Adjacent to Malheur NWR , managed by USFWS, is Diamond Craters, designated
by BLM as An Outstanding Natural Area. Diamond Craters was named for the
diamond-shaped cattle brand of an early settler. Within a 22 square mile
natural area south of Malheur Lake, over 100 cinder cones and craters can
be seen, 30 of which are located inside a 3,500 foot wide caldera which
collasped to a depth of 200 feet. Initally about 9 million years ago vents
here pumped out ash and lava to cover 7,000 square miles of southeast Oregon
in layers up to 130 feet thick. This initial activity was followed by a
series of explosions and instrusions 2,500 years ago forming small cinder
cones accompanied by vast new lava flows. (See above images) Lava cones,
ropy flows, cinder cones, and spatter cones are noted. Vegetation includes
a marsh community in the NW corner of the site which contains a pollen record
of climate going back thousands of years. Other vegetation includes; big
sagebrush, greasewoood, and juniper whenever they can sink roots; and low-growing
pioneer plants adapted to the volcanin surface.
Sources
Orr, E.L., Orr, W.N., and Baldwin, E.M., Geology of Oregon ,
4th Ed., 1992. Kenall/Hunt, Dubuque, Iowa.
Perry, John, and Perry Jane G., The Sierra Guide To The Natural Areas
of Oregon and Washington.. 1983. Sierra Club Books, San Francisco,
California.
Copyright
Phil Kessinger, 1997
Eugene,Oregon USA
All Rights Reserved
phil_k
at
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Revised December 2002