BYU - PHY S 100 - Chapter 27, Week 12 Notes - Class Notes

Created by: Erica Bassett Elite Notetaker

Schools > Brigham Young University > OTHER > PHY S 100 > BYU - PHY S 100 - Chapter 27, Week 12 Notes - Class Notes

School: Brigham Young University

Department: OTHER

Course: Physical Science

Professor: Patricia Ackroyd

Term: Spring 2017

Name: Chapter 27, Week 12 Notes

Description: Tectonic Plates, Seafloor spreading, hot spots

Uploaded: 12/10/2017

This preview shows page 1 of a 2 page document. to view the rest of the content

Chapter 27: Continental Drift and Plate Tectonics Evidence for Continental Drift
Jigsaw Fit of the Continents • Wegener termed Pangaea, noting that the continents fit together in a jigsaw shape
Continental Structure • Structural trends cross continents, hinting at a combined land mass (ex: mountain belts)
Paleontological (Fossil) Evidence • Similar fossils live in widely separated lands; dinosaurs incapable of crossing large bodies of water
manage to leave fossils in continents separated by oceans
Paleoclimatic Evidence • Rocks give us clues about ancient climates; tell us that eastern South American, India, Southern
Africa, and Southern Australia had the same climate as Antarctica (ancient glaciation formed one
single region)
Paleomagnetic Evidence • Basaltic lava leaves a magnetic field on land; continents have same orientations of magnetic fields
when aligned in Pangaea shape    Seafloor Spreading • Studies of ocean floor in 50s and 60s led to discovery of the mid-Atlantic ridge, which matches
exactly with drift pattern   o Discovered ridges and trenches    The Theory of Tectonic Plates Magnetic Reversals and Stripes on the Seafloor • Every 1/2 million years, earth's polarity has flipped • Development of magnetic stripes of reversing polarity --> lava comes up at oceanic ridge, pushing
the seafloor to the sides Earthquakes and Plate Boundaries • Earthquakes happen at ocean trenches and ridges • Biggest tectonic plate: Pacific      Parts of Tectonic System Divergent Plate Boundaries • Two plates pull away from each other --> lava rises up and solidifies, pushing plates apart
Convergent Plate Boundaries:   • Ocean-ocean plate collisions o Subduction: in a collision, one plate will dive under the other and sink into the
Asthenosphere (lower density plate underneath) o Creates massive earthquakes and volcanic eruptions

This is the end of the preview. Please to view the rest of the content