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