THE LANGUAGE OF THE EARTH – PART V

PLATE TECTONIC THEORY

Plate Tectonic TheoryPlate Tectonic Theory The Earth’s outer shell (lithosphere) is composed of rigid plates that are moving relative to one another.

Internal Structure of the EarthInternal Structure of the EarthCompositional Layers

Physical Layers

Plate Tectonics Drives Two Stages of Crust-makingPlate Tectonics Drives Two Stages of Crust-making A. Mantle partially melts to make ocean crust B. Ocean crust partially melts to make continental crust

What Moves the Plates?What Moves the Plates?

Mantle Push Ridge Slide

Slab Pull

Types of Plate BoundariesTypes of Plate Boundaries

Divergent Plate BoundariesMid-ocean RidgesMid-ocean Ridges

Where Stage 1 Crust is Made

BasaltBasaltRock Type of the Ocean Crust

Pillow Lavas

Remember:Melting the mantle makesmafic magma!! Always

Hydrothermal Alteration of Ocean CrustPreparing it for Stage 2 Melting

““Black Smokers”-Black Smokers”- metal-rich hydrothermal waters venting into the ocean floor

Continental Rifting The creationof new ocean basins

Continental Rifting Continental Rifting and and

The Break-up The Break-up of Pangeaof Pangea

Age of the Atlantic Ocean CrustRecording the Break-up

Beginning the Break-up225 Ma

Youthful Oceanic Crust Youthful Oceanic Crust

Convergent BoundariesConvergent Boundaries Making 2nd Stage Crust

Ancient Continental Crust

Convergent Boundaries-Convergent Boundaries- Where the Action Is!!

Ocean-Continent

Continent - Continent

Ocean - Ocean

Earthquakes

Volcanoes

Mt. St. HelensMay 18, 1980

Consequences of ConvergenceConsequences of ConvergenceExplosive Volcanism

Consequences of ConvergenceConsequences of ConvergenceMountain Building and Rock Deformation

Consequences of ConvergenceEarthquakes

Banda Ache, Dec. 26, 2004

OROGENESISOROGENESISThe Culmination of Convergence

Transform Transform Fault Plate Fault Plate BoundariesBoundaries

San Francisco EarthquakeApril 18, 1906 Mag 7.8The San The San

Andreas FaultAndreas Fault

Mantle Mantle Plumes/Plumes/HotspotsHotspots

Mantle Mantle Hotspots in Hotspots in the Oceansthe Oceans

Sites of overthickened crust and the formation of ocean islands and plateaus

Famous Hotspots

Hawaii

Yellowstone

Iceland

The Grand Unifying Theory of the EarthThe Grand Unifying Theory of the EarthParadigm -