Earth's Layers & Materials
What are the three main layers of Earth?
Crust, Mantle, Core
What theory explains how Earth’s surface moves?
The Theory of Plate Tectonics
What do fossils tell us about Earth’s history?
What organisms lived and what the environment was like
What did Wegener name his "supercontinent"?
Pangaea
What is the difference between the lithosphere and asthenosphere?
Lithosphere = rigid outer layer; Asthenosphere = soft, flowing layer below
What happens at a divergent boundary?
Plates move apart, forming new crust
What is the geologic time scale?
A record of Earth’s history based on rock layers and fossils
Wegener saw that the continents fit together like _________?
Puzzle pieces
What type of rock forms from cooled magma or lava?
Igneous Rock
What happens at a convergent boundary?
Plates move together — one may subduct, forming mountains or volcanoes
What is an index fossil?
A fossil used to define and identify geologic periods (there are MANY of them!)
What was the name of Wegener's theory?
Continental Drift
What is a convection current and where do these happen in Earth's layers?
A convection current is the cycle of hotter rock rising and cooler rock falling in a cycle. Convection currents occurs in the mantle.
What happens at a transform boundary?
Plates slide past each other, often causing BIG earthquakes
Put the categories of the GTS in order from biggest to smallest.
Eon, Era, Period, Epoch.
What evidence did Wegener have to support his theory?
2) Fossils
3) Mountain and Rock correlation
4) Paleo and climate data
How does density affect Earth’s internal structure?
Denser materials sink to the core; lighter materials rise to form the crust
What evidence supports the theory of plate tectonics?
Continental fit, fossils, rock formations, and sea-floor spreading
Cause & Effect! Events on Earth, lead to extinctions, lead to changing plants and animals.