Amboy, California

Location: 35.5N, 115.8W
Elevation: 984 ft (300 m)
Photo By Mike De Marquette

Amboy Crater is located in the Mojave desert in California off of Interstate 40 just West of the town called Amboy. Amboy lava field is made-up mostly of vesicular pahoehoe. It covers 43.5 sq miles (70 sq km). The oldest lava flows are found in the eastern and southeastern parts of the field. These old flows have many depressions (up to 32.8 ft (10 m) around and several meters deep) formed from collapsing. Two other types of flows can also be found in Amboy: platform units and vent lavas. Platform units are isolated parts of the flow with fairly flat surfaces. Vent lavas are found over some of the vents of the Amboy lava field. They are made of relatively dense pahoehoe. Separate craters are found in the middle of the lava ponds where lava may have drained back into the vents. The surface of the field is covered with wind-blown material. These deposits get thicker towards the southwest.

Amboy Crater is a large, uneroded cinder cone. It is found in the northeastern part of the Amboy lava field. The Amboy cone which 246 ft (75 m) tall and 1508 ft (460 m) around at the base has had at least 6 eruptive phases. It is believed to be approx. 6000 years old and has both lava types pahoehoe and aa lava, vesicular basalt and vent lavas also as well as conglomerate ejecta and lava bombs. Amboy Crater is actually made of at least four cones nested inside of each other. The outside of the main cone has many trenches carved in it by erosion. Part of an old cone can be found within the west side of the main outer cone. Both of these cones open to the west.


Sources:

Wood, Charles A. and Jurgen, Kienle, "Volcanoes of North America," Cambridge University Press, Cambridge, 354 pp., 1990.

Parker, R.B., 1963. Recent Volcanism at Amboy Crater,San Bernardino County,California: Special Report 76, California Division of Mines and Geology



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