Plate Tectonics
What is the name of the supercontinent that existed millions of years ago?
Pangaea
What are the three main rock types
What are igneous, sedimentary, and metamorphic rocks?
Approximately how old is Earth?
4.6 billion years old
What are the four layers of Earth?
crust, mantle, outer core, and inner core
What type of rock often contains fossils?
sedimentary rock
What causes tectonic plates to move?
convection currents
What mineral property describes how a mineral reflects light?
luster
What law says the oldest rock layers are on the bottom?
Law of Superposition
Which layer is made mostly of liquid iron and nickel?
outer core
What process breaks rocks into smaller pieces?
weathering
What type of plate boundary occurs when plates move apart?
divergent boundary
What is the hardest mineral on the Mohs Hardness Scale?
diamond
What are index fossils used for?
determining the relative age of rock layers
Which Earth layer do tectonic plates move on?
What is the mantle (asthenosphere)
What is the Ring of Fire?
area around the Pacific Ocean with many earthquakes and volcanoes
What type of plate boundary forms mountains?
convergent boundary
What type of rock forms from cooled magma or lava?
igneous
What is radioactive decay used to determine?
absolute age of rocks and fossils
Which layer is the hottest?
inner core
Why are fossils rarely found in igneous rock?
heat from magma destroys fossils
What type of boundary is most associated with earthquakes in California
What is a transform boundary
What causes metamorphic rocks to form?
heat and pressure
What major event helped cause the extinction of dinosaurs 66 million years ago?
asteroid impact
What is the rigid outer layer of Earth called?
lithosphere
What happens during a subduction zone?
one tectonic plate sinks beneath another plate