GEOG 2300 1st Edition Lecture 36Outline of Last Lecture I. Ways to Help the OceanII. Protecting Aquatic Biodiversity DifficultiesIII. Ocean FloorIV. Earth’s StructureOutline of Current Lecture I. Earth’s StructureII. Plate TectonicsIII. Plate BoundariesCurrent LectureI. Earth’s StructureA. Lithosphere: the solid upper part of the mantle plus the crust, it is discontinuousB. Asthenosphere: the layer of soft, plastic rock in the mantle, below the lithosphereC. The stiff, brittle lithosphere moves over the asthenosphereD. Lithosphere is fragmented into lithospheric plates (tectonic plates)II. Plate TectonicsA. The earth is hot inside, from heat when the earth was createdB. Forces that push, move, and raise earth’s surface – driven by internal heatC. Forces that scour, wash, and wear down – driven by the sunD. On continents: young dynamic alpine belts – mountain and island arcs, old stable continental shields – low lying older areas of igneous and metamorphicrocksE. Oceans: extensive smooth abyssal plains, long narrow mid-oceanic ridgesF. Which is not a true description of a layer of the earth? The oceanic crust is the thickest layer of the earth and is composed of felsic rocksG. 1915 Alfred Wegener: proposed that landmasses once united (Pangea) – splitinto Laurasia and Gondwanaland H. During this time, land masses have formed and moved (continental drift)I. Lithospheric plates: 7 major plates and many smaller ones, convection cells within the earth’s interior drag the crust alongThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.J. Which best describes the Moho? The transition zone from mantle to crust where seismic waves speed up because of density changes in the rocksIII. Plate BoundariesA. Divergence: seafloor spreading, new crust is created and forced outwards from a rift, upwelling magma creates new crust, Mid-Atlantic ridge at Iceland – 1.8 cm per year, South Atlantic – 4 cm per yearB. Convergence: collisions, ocean – land convergence = subduction: continental crust is lighter so oceanic plate subducts underneath, earthquakes get deeperalong this plate boundary, large earthquakes, volcanism, mountain ranges, ex:Nazca and South American plates (7.4 cm per year); oceanic – oceanic convergence = produces deep ocean trenches and many volcanoes, ex: NorthAmerican and Pacific plates (Aleutian Islands); continental – continental convergence = produces thick land masses, earthquakes, but little volcanism, ex: Eurasian and Indian platesC. Lateral:
View Full Document
Unlocking...