GEOL 1001 : Geology Exam 2
Document Summary
Mafic = low silica, high fe and mg. Ryolitic = opposite of mafic (mafic) lava: very hot, low silica, and low viscosity. Pillow basalt = rounded blobs of basalt that cooled underwater. Rhyolite, has the highest sio2, is the most viscous lava. Pyroclastic flows (also called nuee ardentes) = an avalanche of hot ash (200 450 c/ ~390-840 f), pulled down the side of a volcano by gravity. Tephra = unconsolidated deposits of pyroclastic grains,regardless of size. Tuff = lithified ash, or ash mixed with lapilli (formed by burying and transforming into rock) Lahars = wet slurry/mixture of ash, coarser debris, and water. The last bubbles to form will freeze into the lava and become holes = vesicles. Caldera = big circular depression resulting from a major eruption and the subsequent collapse of the center of a volcano into the large, drained magma chamber below.
