GEOL 1001 : Geology Exam 2
Document Summary
Columnar jointing: lava flows contract because rocks shrink when they lose heat, then the rocks fracture into polygonal columns. Andesitic: because of its higher silica content and thus its greater viscosity, _____ cannot flow as easily as basaltic lava. Blocky lava: in andesitic lava, when formations dry they can become a jumble of rubble called _____ Rhyolitic: lava flows that have broken blocky surfaces. Basaltic lava: lava with low viscosity and can flow long distances. Andesitic lava: lava that is too viscous to flow far and tends to break up as it flows. Felsic lava: so viscous that is may pile up in a dome-shaped mass. Pyroclastic debris: lava that flies into the air and freezes. Pel "s hair: flying lava droplets that have a strand hanging from them. Pel "s tears: droplets of lava that freeze in the air. Viscosity: resistance to flow; depends on chemical composition, temperature, gas content, crystal content.
