GEOG 170A1 Lecture 16: GEOG 170- Earth’s Environment: Introduction to Physical Geography - Lecture 16: Physical Parts of Earth Day 3
14 Nov 2014
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Geog 170- earth"s environment: introduction to physical geography - lecture 16: Earth"s crust is born of upwelling magma: Balsaltic magma becomes new oceanic crust, which migrates on a collision course with the continents. Dense basaltic crust does it"s subduction dive" under the less dense continental masses, remelting and thrusting magma upward, making volcanoes. Mountains are built several ways, but one big way is when the dense basaltic crust slams" into the continental plate, buckling it and forming mountains. Some mountains (like the high himalayas) are formed by the convergent collision of plates on the same continent. Terranes are chunks broken off one plate and fused to another via tectonic forces. Continental crust is deformed by tectonic forces that pull, push or shear big pieces of crust. It always has worked that way; always will and that"s what"s meant by uniformitarianism:
