GEOG 574 Lecture Notes - Lecture 3: Magma Chamber, Tephra, Continental Margin
Document Summary
Igneous activity - magma rises through the lithosphere creating igneous landforms within and. Lava - magma after it reaches the surface. Extrusive - magma erupts and solidifies on the surface. Most volcanic landforms form along plate boundaries except for hot spots. Spreading centers - mid-ocean ridges, rift valleys, continental flood basalts. Pyroclastic - explosive eruption of solid rhyolitic ash and tephra. Low relief comprised of layers of mafic lava flows. High relief comprised of alternating ash and lava layers. Footwall - rocks on the side of fault that miners were standing. Shield volcanoes - effusive basalt lava flows form large, gentle sloping landforms. Cinder cones - eruption of basaltic tephra, small weak sided cone shape. Strato (composite) volcanoes - intermediate materials, tall steep-sided cone shaped. Purely transform movement limited to short sections irregularities result in micro/meso-scale. Transverse orogens - sharply defined upland areas where sides of a fault collided.
