Search results
Results From The WOW.Com Content Network
Geologic map of the Sonoma Volcanics. The Sonoma Volcanics are a geologic formation of volcanic origin that is widespread in Napa and Sonoma counties, California.Most of the formation is Pliocene in age and includes obsidian, perlitic glass, diatomaceous mud, pyroclastic tuff, pumice, rhyolite tuffs, andesite breccias and interbedded volcanic lava flows.
Obsidian flows which are so large that they can be hiked on are found within the calderas of Newberry Volcano (Big Obsidian Flow, [28] 700 acres) and Medicine Lake Volcano in the Cascade Range of western North America, and at Inyo Craters east of the Sierra Nevada in California.
Edziza obsidian found in coastal areas of southeast Alaska. Edziza obsidian is a naturally formed volcanic glass found at the Mount Edziza volcanic complex in northwestern British Columbia, Canada. It occurs in at least four geological formations of the volcanic complex and was widely used by indigenous peoples during the pre-Columbian era.
Before Obsidian Butte was emplaced and thus became available for obsidian production, people in the region used obsidian from the Coso volcanic field; [44] this trend away from Coso towards Obsidian Butte was recognized even before the exact timing of the Obsidian Butte eruption was known. [42] How the magmas are formed is controversial.
Name Elevation Location Last eruption meters feet Coordinates; Malumalu: Last 8,000 years Ta‘u-931: 3054: 30,000 years ago [15]: Ofu-Olosega: 639: 2096: 1866 unnamed submarine cone eruption
[189] [190] It occurs over an area of more than 2,200,000 km 2 (850,000 sq mi), making MEVC obsidian the most widely distributed obsidian in western North America. [ 189 ] [ 191 ] Obsidian from the Hidden Falls archaeological site in Alaska has yielded a hydration date of 10,000 years; this suggests the MEVC was being exploited as an obsidian ...
In those events, volcanic ash reached from the Pacific ocean to Canada to Mexico. They tend to reoccur about every 600,000 to 800,000 years , according to the U.S. Geological Survey. The most ...
Panum Crater is a volcanic cone that is part of the Mono–Inyo Craters, a chain of recent volcanic cones south of Mono Lake and east of the Sierra Nevada, in California, United States. Panum Crater is between 600 and 700 years old, and it exhibits all of the characteristics of the textbook rhyolitic lava dome .