Earth 16 Items Flashcards
Mantle
middle layer of the Earth
Core
innermost layer of the Earth
Crust
outermost, thinnest, and most solid layer of the Earth
Theory
idea used to explain observed facts
Geologic Time Scale
units of time that divide the Earth’s history
Index fossil
fossil used to determine the age of rocks
Extinct
no longer existing on the Earth
Fossil
the preserved remains of an ancient plant or animal
Continental Drift Theory
theory that continents were a single mass that broke up and drifted to present positions
Plate Tectonics Theory
theory that crust of the Earth is made up of sections, called plates, that are in motion
Sea-floor spreading
process by which new sea floor forms as tectonic plates move
Faults
cracks in Earth’s crust where blocks of rock have moved
Epicenter
point on Earth’s surface that is directly above the focus of an earthquake
Convergent boundary
a place where the Earth’s plates come together
Divergent boundary
a place where the Earth’s plates separate