HARTMAN MULTIMEDIA
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HARTMAN MULTIMEDIA
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In this extensive volcanic field there are at least 26
cones and their associated lava flows. Two
stages of volcanism are represented, one early Pleistocene, the other late
Pleistocene or Recent, possibly only a few thousand years ago.
(One estimate places the latest activity at less than 3,000 years ago.)
Most of the cones and some of the flows are very young. The older sequence, in the eastern part of the field,
consists of layers of pyroclastics and olivine basalt flows some 30 meters (100
feet) thick, resting on a granitic floor. This
older volcanic sequence has been dissected and stripped from a considerable
area. Some of the older volcanoes are in advanced stages of dissection which has
resulted in spine-like protuberances. More recent volcanic activity consists of cinder cones
and basalt flows which have been extruded onto the platforms of the earlier
flows in places and onto the lower granitic rock surface in other portions. There are stands of Joshua trees, Yucca brevifolia, and
associated vegetation in the area. The
uncommon Yucca brevifolia var. jaegeriana is found here.
Indian traces are present. Integrity: Several
of the cones, particularly on the eastern edge of the field, have been quarried
for cinders and there are roads leading to them.
There is a landing strip. Use: Educational,
research, light recreation. Ref: Hewett,
D. F. 1954.
Geology and Mineral Resources of the Ivanpah Quadrangle,
Nevada-California. U. S. Geol. Surv. Prof. Paper No. 275, 172 pp. December 1975
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