Ask a Geologist: Plate Tectonics By: Christian Rowan About Me Christian Rowan ● I am a graduate student in the Department of Earth and Planetary Sciences. ● I study structural geology. ● I like to hike and camp. ● My favorite landscape features are mountains! Ask A Geologist Series Plate Tectonics ● Earth’s surface is broken up into large plates ● These plates move very slowly by processes deep in the Earth NASA Ask A Geologist Series North American Plate NASA Ask A Geologist Series Crust (0-100 km) Earth’s Structure USGS Ask A Geologist Series Mantle (2,900 km) Earth’s Structure USGS Ask A Geologist Series Core (6,378 km) Earth’s Structure USGS Ask A Geologist Series Lithosphere (“rocky+sphere”) ● Crust + upper most solid mantle ● Made up of rock (rigid, hard) Ask A Geologist Series Asthenosphere (“weak+sphere”) ● Upper mantle ● Solid but capable of flowing (like Jell-O!) Ask A Geologist Series Lithosphere Asthenosphere The lithosphere “floats on” the asthenosphere due to differences in the properties of the solid (rigid vs. putty-like solid). Ask A Geologist Series Convection currents cause plates to move! ● Convection in the asthenosphere ● Carries heat from Earth’s core to the surface Convection currents in a boiling pot of water Heat Source (Flame) Ask A Geologist Series Plate movement driven by convection currents and slab pull Wiki Ask A Geologist Series As plates move around the globe… What happens when plates encounter each other? Ask A Geologist Series Plate Boundaries Convergent (Plate move together) Divergent (Plates move apart) Transform (Plates move past) Wikimedia Ask A Geologist Series Plate interactions at boundaries creates the topography we see on Earth! Let’s go exploring… Wikimedia Ask A Geologist Series Where do convergent plate boundaries occur? Himalayas Andes Mountains Ask A Geologist Series Where do divergent plate boundaries occur? Mid Ocean Ridge East Africa Rift Valley Ask A Geologist Series Where do transform plate boundaries occur? San Andreas Fault Ask A Geologist Series Plates move very, very slowly ● 2-5 centimeters per year ● Comparable to the the rate Given enough time, of fingernail growth! plates moving very slowly can form supercontinents like Pangea! Ask A Geologist Series Global Paleogeography: Present Day to 600 Ma All images: coyright Ron Blakey, Northern Arizona University & Colorado Plateau Geosystems, Inc. Ask A Geologist Series Present Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series Pleistocene Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 20 Ma: Neogene Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 35 Ma: Oligocene Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 50 Ma: Eocene Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 65 Ma: K/P boundary Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 90 Ma: Late Cretaceous Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 105 Ma: Cretaceous Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 120 Ma: Early Cretaceous Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 150 Ma: Late Jurassic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 170 Ma: Jurassic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 200 Ma: Early Jurassic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 220 Ma: Late Triassic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 240 Ma: Early Triassic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 260 Ma: Late Permian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 280 Ma: Early Permian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 300 Ma: Late Carboniferous Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 340 Ma: Early Carboniferous Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 370 Ma: Late Devonian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 400 Ma: Early Devonian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 430 Ma: Silurian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 450 Ma: Late Ordovician Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 470 Ma: Middle Ordovician Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 500 Ma: Late Cambrian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 540 Ma: Early Cambrian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 560 Ma: latest Proterozoic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 600 Ma: Late Proterozoic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series Now let’s go forward in time from 600 Ma to the Present! Ask A Geologist Series 600 Ma: Late Proterozoic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 560 Ma: latest Proterozoic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 540 Ma: Early Cambrian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 500 Ma: Late Cambrian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 470 Ma: Middle Ordovician Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 450 Ma: Late Ordovician Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 430 Ma: Silurian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 400 Ma: Early Devonian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 370 Ma: Late Devonian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 340 Ma: Early Carboniferous Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 300 Ma: Late Carboniferous Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 280 Ma: Early Permian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 260 Ma: Late Permian Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 240 Ma: Early Triassic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 220 Ma: Late Triassic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 200 Ma: Early Jurassic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 170 Ma: Jurassic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 150 Ma: Late Jurassic Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 120 Ma: Early Cretaceous Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 105 Ma: Cretaceous Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 90 Ma: Late Cretaceous Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 65 Ma: K/P boundary Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 50 Ma: Eocene Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 35 Ma: Oligocene Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series 20 Ma: Neogene Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series Pleistocene Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series Present Image: coyright Ron Blakey Slide courtesy of: Roy Schlische Ask A Geologist Series Why Do We Care? Geohazards ● Earthquakes are caused by the movement of plates! Ask A Geologist Series Why Do We Care? Evolution ● The movement of plate helps us understand the evolution of plants and animals! Ask A Geologist Series Why Do We Care? Long-term climate ● The creation, destruction, and movement of continents/oceans has great influence on long-term climate change. Ask A Geologist Series Question Time!.