Archean felsic volcanic rocks lenticular fiamme. When hot pumice deposits on a cool surface, it is rapidly cooled, recrystallised and welded into quartz with flame-like ending tips. The eutaxiitc texture represents a hot vapour-phase emplacement of the fragmented volcanic materials on the Earth's surface. Flow bands are present in massive, uniform felsic lava flow units. When the viscous lava flow encounters a surface, friction drags the mobile lava and forms internal banding. Structureless hyaloclastite is commonly found in Archean felsic volcanic rocks. In submarine environments, water quenches and cools lava rapidly during volcanic eruption. The flow is fragmented and form glassy volcanic breccia. The
Geology of Guam a foot, which dropped to 0.05 feet further inland. The Guam Waterworks Authority, Guam Environmental Protection Agency, the Air Force and the Navy manage the 180 wells throughout the island. A combination of high-permeability rock, over pumping and overcrowding of wells resulted in 32% of wells (measured in data from the early 1960s through 1997) exceeding a guideline of 250 mg/L chloride concentration. Geology of Guam The geology of Guam formed as a result of mafic, felsic and intermediate composition volcanic rocks erupting below the ocean, building up the base of the island in the Eocene, between 33.9 and 56