GPHY 102 Lecture 16: Volcanic and Tectnoic Landforms
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Initial or primary: directly produced by volcanic and tectonic activity, sequential or secondary. Shaped by processes of, and agents of denudation: vectors of earth movement, erosion and deposition are important. Volcanoes: conical or dome-shaped initial landform built of lava and ash emitted from a vent in earth"s crust, active: erupted in recorded history. "volcanoes 101" (link in slides: dormant: not seen to erupt, but evidence suggests recent activity and they could erupt again, extinct: no sign of activity; evidence of long-term weathering and erosion, will not erupt again. Stratovolcanoes: also called composite volcanoes, mostly formed over subductive margins. Stratified, layers of ash and tephra (relates to clastic fragments that are deposited from the volcano: typically, felsic lava, which holds large amounts of gases, under pressure, eruptions hence can be explosive, sends fragments flying into the air. Felsic lava is highly viscous and resists flow (tall, steep-sloped cones)
