Geography 2152F/G Lecture Notes - Lecture 1: Transform Fault, Seafloor Spreading, Oahu
17 Feb 2022
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Document Summary
Throughout earth"s 4. 6-billion-year history, the materials on or near the surface have been created and modified by physical and chemical processes. Collectively, these processes are called the geologic cycle, which encompasses the following: This cycle involves the creation, movement, and destruction of tectonic plates. Tectonic plates: large blocks of the earth"s crust that form its outer shell; there are 14 plates. New land is formed at mid-ocean ridges and land is destroyed at subduction zones. The process is driven by earth"s internal energy. There are 7 large plates (housing the 7 continents) and 7 smaller plates. A subduction zone is an area where one plate sinks beneath another plate. The inner core is extremely hot and solid. The asthenosphere (upper mantle) is composed of hot magma with some flow. The lithosphere is a thin and brittle crust. The crust forms the upper part of the lithosphere and is broken into fragments (plates). Continental: relatively buoyant, thick (averages 30 km thickness)
