Chapter 4 wrapup

Extra Credit Option: Attend the Public Lecture by Prof Antonio Lazcano on Tuesday (tomorrow) evening, Feb 11 at 7:30 PM in Gammage Auditorium here on campus Write up a short summary 2-3 paragraphs for the talk, highlighting the aspects you found most interesting Bring your write-up to class on Wednesday Be sure to write your name and ASU ID at the top of the page Today’s Lecture:  Plate margins and associated geological pheneomena - Intraplate hot-spots - Divergent plate margins in continental settings (origin of new ocean basins) - Convergent margins - Continental margin settings - Transform margins (ridge transforms and onland transforms  Brief Review  Quiz  Next time: Interlude A and Chapter 5! PLATE TECTONICS Location of Earth’s Hot-spots PLATE TECTONICS Yellowstone Hot Spot PLATE TECTONICS Yellowstone Hot Spot PLATE TECTONICS Types of Plate Boundaries types ● divergent boundaries ● convergent boundaries ● transform fault boundaries PLATE TECTONICS Continental Rifting: East Africa Red Sea (looking southeast) PLATE TECTONICS Opening of the Red Sea PLATE TECTONICS Opening of the Red Sea PLATE TECTONICS Formation of Triple Junctions ocean-continent ocean-ocean continent-continent Types of Convergent Plate Margins Types of Continental Margins “Active”  Found along convergent plate margins:  Primarily around the Pacific rim  Characterized by active narrow continental shelves and active mountain building processes (earthquakes & volcanic activity)  Accretionary wedges of sediment which are scraped off the top of a subducting slab Types of Continental Margins “Passive”  Found within plate interiors:  Continental margin not = a plate margin Examples are continental margins around Atlantic  Broad continental shelves consist of thick wedges of sediment deposited along margins  Few earthquakes or volcanic eruptions Comparison of Active and Passive Continental Margins PLATE TECTONICS Transform Plate Margins ● Transform fault boundaries Strike-slip faults where plates slide past each other: No production/destruction of material Most connect mid-ocean ridge segments Others are “on-land” transforms like the San Andreas Fault PLATE TECTONICS Transform Plate Margins On-Land Transform Faults San Francisco Peninsula and San Andreas Fault In-class exercise Name: GLG 101 Prof Far m er ASU ID: Compare the continental margin of the west coast of S America with the east coast of N America 1) South Am 2) North Am Questions: a) Active or passive continental margin? b) Draw a cross-section (a side view) of each area, labeling the most important features