Ubehebe Craters volcanCratères Ubehebe sont un groupe de maars (cratères d'explosion) formé à la marge occidentale de la montagne de Tin, en Californie.
Introduction:The Ubehebe Craters consist of an isolated group of overlapping maars formed during eruptions of alkali basalt along a fault cutting fanglomerate deposits on the flanks of Tin Mountain in Death Valley National Park. Ubehebe Crater is a 0.8-km-wide, 235-m-deep maar surrounded by a tuff ring. Little Hebe Crater, the second youngest vent, is located immediately south of Ubehebe Crater and is a small tuff cone with a 100-m-wide crater overlain by pyroclastic-surge deposits. At least a dozen craters are located within an area of 3 sq km, and bedded pyroclastic-surge deposits cover an area of 15 sq km. Early scoria cone formation was followed by hydrovolcanic explosions that formed two clusters of explosion craters and tuff rings. The age of volcanism at Ubehebe is not dated precisely, but the lack of erosional modification of pyroclastic-surge deposits suggests that the youngest activity, from the largest crater, Ubehebe Crater, is Holocene in age. Relationships between Ubehebe tephra and approximately dated archeological artifacts suggests an age of about 6000 years.
from: GVP Ubehebe Craters information
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