Guided Exploration: Plate Tectonics
Part of Hall of Planet Earth.
What is Plate Tectonics?
1. Bronze Globe
Observe this model to explore the solid Earth — what the Earth looks like without water. (To understand the term “solid Earth,” watch the Dynamic Earth sphere overhead and see the liquid slowly drained away from the rocky surface). Compare the familiar topography of the continents with the less familiar topography of the ocean basins. Then look at the “slice of crust” model hanging overhead. Use the diagram below to find the region on the globe that’s represented in the model above. In this part of the hall, you’ll be exploring the ways in which plate tectonics shapes the solid Earth.
2. Churning Earth Section
Convection is the main way in which heat is lost from the interior of the Earth. It’s the force that drives the movement of tectonic plates. Go to the video kiosk in the circular table and watch scientific models of how the Earth’s core and mantle convect.
When Plates Collide
3. Model of Collision
When an oceanic plate meets a continental plate, the oceanic plate descends, or subducts, beneath the continental plate and sinks into the mantle. Explore the model and use your hands to simulate how plates collide.
4. Explosive Volcanism Section
Explore why most explosive eruptions occur in volcanoes above subduction zones. Examine samples from Medicine Lake Volcano, California (#5-10), and watch a video of scientists at work in Indonesia.
5. Mountain Formation Section
When two continental plates meet, one is thrust over the other to form mountain ranges like the Alps and the Himalayas. Watch the video and examine the sand model, and think about how the model helps scientists understand the way plates interact to form mountain ranges. Then observe the rock samples (#1-7) that illustrate the processes (uplifting, folding, crustal thickening, and faulting).
When Plates Move Past Each Other
6. Model of Slip
A fault forms when oceanic or continental plates slide past each other in opposite directions, or move in the same direction but at different speeds. Explore the model and use your hands to simulate how plates move past each other.
7. Earthquakes Section
Earthquakes occur along fault lines (cracks near plate boundaries where the crust on opposites sides moves). Explore the earthquake video kiosk and associated text panels to find out how monitoring helps scientists estimate the odds of an earthquake taking place within a certain period of time. Then find the faults on the two large casts and the samples (#1-2) and examine what they tell us.
When Plates Separate
8. Model of Separation
Most spreading plate boundaries are found in ocean basins. Explore the model and use your hands to simulate how plates separate.
9. Basalts
Most volcanoes erupt basalt, a fluid lava from the mantle that forms flows. Most basalt erupts from cracks in the seafloor, but some basaltic lava flows occur on continental crust. Compare the shapes of the underwater (#9-17) and flood basalts (#18), and explore their formation.
When Plates Move
10. Hawaiian Hot Spots
Basaltic lava also erupts at hot spots, where molten rock, or magma, forms in plumes of hot rock that rise from deep in Earth to penetrate a moving plate above. Watch the video and explore the various specimens. What does the pattern of the Hawaiian island chain reveal about how the Pacific plate is moving?
Wrap Up
11. Bronze Globe: Revisit the globe and connect specific specimens to places on the globe and to the tectonic processes at work behind them. (Examples: Collide — Andes and Himalayas; Separate — Mid-Atlantic Ridge; Slip — San Andreas fault)