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Explore the fascinating world of plate tectonics, from ridge push to convergent boundaries, and learn about the creation and destruction of seafloor. Discover continental rifting examples, convergence types, and the impact of tectonic processes on Earth's surface.
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Plate Tectonics - the Finale! • Exam Logistics – • Wednesday, in class, bring #2 pencil or a black or blue pen • Please fill every seat, put everything away upon arrival • Be sure you mark which exam “version” you have • BRING YOUR BU ID • **No Class Friday, watch the video online instead.** • October 1 – we will learn about ocean sediments, read Ch. 5
I am looking for 1 - 2 new interns: • We work on human impacts on coastal systems • Need to be available at least 6 hours per week • Check out website: www.fulweilerlab.com • Then if interested: • Send me an email w/ subject: fall 2018 intern • Send resume/cv and brief explanation as to why you’re interested.
Movement caused by plate tectonics 1.Divergent Plates: 2.Convergent Plates 3.Transform Plates
At point 3 below, seafloor is being: • Created • Destroyed • Neither
At point 1 below, seafloor is being: • Created • Destroyed • Neither
Types of Spreading Centers • Oceanic rise • Fast-spreading • Gentle slopes • East Pacific • Oceanic ridge • Slow-spreading • Steep slopes • Mid-Atlantic • Ultra-slow • Deep rift valley • Widely scattered volcanoes • Arctic and southwest India
Mid Atlantic Ridge splitting Iceland Example of Continental Rifting Thingvellir, Iceland Krafla volcano
Convergent Plate Boundaries Regions where plates are pushing together. Compression produces buckling and shortening. Oceanic crust destroyed Ocean trench Volcanic arc Great forces involved Mineral structure changes associated
Three types: 1. Ocean-Continent 2. Ocean-Ocean 3. Continent-Continent
1. Ocean-Continent Convergence Tectonic process – Subduction Ocean –Continent crust interaction Old Sea floor is destroyed
Convergent Plate Boundaries 2. Oceanic-Oceanic Convergence • Denser plate is subducted - Old Sea floor is destroyed • Deep trenches generated • Volcanic island arcs generated
3. Continent-Continent Convergence Example - The Himalayas Tectonic process – Collision – no Subduction Continent-Continent crust Interaction Sea Floor is not created or destroyed…
Transform Example - The San Andreas Fault Tectonic process – transform faulting Continent-Continent and Ocean crust interaction Sea floor is not created or destroyed…
Oceanic - Btw. MORs Continental - San Andres Fault
Applications of Plate Tectonics • Mantle Plumes and Hotspots • Intraplate features • Volcanic islands within a plate • Island chains • Record ancient plate motions
Loihi – 1 km below sea level – will be at the surface in 30,000 to 100,000 years…
Plate Tectonics and Intraplate Features • Seamounts • Rounded tops • Tablemounts or guyots • Flattened tops • Subsidence of flanks of mid-ocean ridge • Wave erosion may flatten seamount.
Fringing reefs – develop along margin of landmass • Barrier reefs – separated from landmass by lagoon • Atolls – reefs continue to grow after volcanoes are submerged
Wilson Cycle….. 6. (Himalayas) 5. (Med Sea) 2. (Red Sea) 4. (Pacific Ocean) 1. (east African Rift Valley) 3. (Atlantic and Arctic Oceans)