Lecture-3-F10

Lecture-3-F10 - EAS 111 General Announcements 8/30/10 •...

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Unformatted text preview: EAS 111 General Announcements 8/30/10 • Schedule Reminder Lab 2 this week: Evidence of Plate Motion Lab 3 next week: Plate Tectonics and Earthquakes Today: – Focus on Plate Margins. How does the big convection story play out in detail at convergent, divergent, and transform boundaries. • Wednesday: Earthquakes Part 1: Dr. Saad Haq, guest lecturer Next Week: M – LABOR DAY 9/6/10: No class for lecture, labs start as usual on Tuesday 9/7/10 W – Earthquake hazards and damage, and The earth’s interior and structure imaged from seismic investigations CPS Practice Starts 9/8/10 – in use for credit Monday 9/13/10 Earth and Atmospheric Sciences 111 Fall 2010 Plate Tectonics: Part 2 -Heat and Heat Transfer -Big amounts of rock in motion -Plate Margins and features – explained by the big picture Lecture 3 Observe the locations of different types of plate boundaries 03.03.c1 Compare these locations with mid-ocean ridges, Compare oceanic trenches, mountains belts, line of islands, etc. oceanic Three Types of Relative Plate Motions Move apart: Move divergent boundary divergent Move toward each other: Move convergent boundary con Move horizontally Move past one another: transform boundary transform 03.03.b1-3 05.04.b4 Convection: Essential Heat transfer IN Earth Essential Convection: How’s it work? Convection: 1. 2. 3. 4. 5. 6. 7. 8. Rock material at the bottom gets hotter than Rock surroundings surroundings Expands Same material in more volume = less dense Density = Mass per amount of volume Less dense than surroundings = floats! Gets to top, cools off, gets more dense Sinks Whole thing goes around again 12.15.c3 03.05.c2 05.04.b5 Convergent Margins Subduction zones and Collisions 03.00.a1b What’s going on here? The rock here is: The A)relatively old and cold A) B)relatively young and hot So it: A) is denser and sinks B) is less dense and floats C) magnetically attracted to the core D) dragged down by space aliens 05.07.b1 03.00.a1d 03.05.d1 03.05.d2 03.05.d3 How could melting occur during a continental collision? Few volcanoes Felsic rocks Felsic (granite) (granite) Burial and heating Burial of crustal rocks of 05.07.c1 Melting during Melting subduction before collision (but shuts off) collision Divergent Margins Spreading Centers and Rifts 03.05.c2 03.06.a2 10.03.a1 Earth’s Magnetic Field Normal magnetic field 10.02.a Liquid outer core contains Liquid convection currents convection Reversed magnetic field Time 1: Time normal polarity polarity Observe how Observe magnetic reversals are recorded by a mid-ocean ridge mid-ocean Time 2: Time reversed polarity polarity Build series Build of magnetic stripes over time time 10.02.c 03.00.a1f What’s going on here? Why is this continental crust being pulled apart? A)the subducting slab on the other end of the plate is pulling on it B) The upwelling mantle is pushing it C)Both could be happening together D)Neither of these 05.06.c1 Transform Margins On and offshore Transform Boundary Observe how these two “plates” are moving Observe past each other past Plates move Plates horizontally past one another one Link other Link types of plate boundaries boundaries 03.06.a1 03.00.a1a Observe plate boundaries near the west coast of Observe North America (green lines are transform boundaries) North 03.06.b1 EAS 111: Assignments for 9/1-8/10 • Exploring Geology – For Wednesday 9/1/10: • 12.0, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6 – Earthquake Basics – For Wednesday 9/8/10: • 12.7, 12.10, 12.12 – Earthquake Damage, Hazards, and Prediction (look over 12.8 and 12.9 lightly) • 12.14, 12.15, 12.16 – Exploring Earth Interior • 1.3 – Earth’s Interior structure ...
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