Chapter 6: Plate Tectonics Section 1 Earth Structure Flashcards
What are the five layers of earth based on physical properties?
The lithosphere, the asthenosphere, the mesosphere, the outer core and the inner core.
What are Earth’s three compositional layers?
The core, the mantle, and the crust.
What is the lithosphere?
The solid, outer layer of earth that consist of the crust and the rigid upper part of the mantle. The lithosphere is divided into pieces called tectonic plates.
What are the pieces of the lithosphere called?
Tectonic plates
What is the Asthenosphere?
The asthenosphere is the soft layer of mantle on which tectonic plates move.
Who was Alfred Wegener?
A scientist who wrote the hypothesis of continental drift
What is continental drift?
The idea that a single large landmass broke up into smaller landmasses to form the continents which then drifted to their present locations.
List three lines of evidence for Continental drift.
- The pattern of fossil locations.
- The location of mountain ranges in similar types of rock
- The distribution of ancient climate zones
What is Pangaea?
A single large continent which gave rise to today’s continents through continental drift. In Greek, “Pangaea” means all Earth.
Briefly describe the movement of the continents over the past 245 million years.
Pangaea broke up into two big pieces called Laurasia and Gondwana. Laurasia and Gondwana broke into smaller pieces which the continents
What is seafloor spreading?
The process by which new oceanic lithosphere or seafloor forms as magma rises the earth surface and solidifies at a mid ocean ridge.
How do magnetic reversals of Earth’s magnetic field prove that the seafloor spreading?
They provide a record of magnetic reversals in the rock which slowly move away from the mid-Ocean ridge.
What is the crust?
The fan and solid outermost layer of Earth above the mantle.
What is the mantle?
The layer of rock between earth’s crust and the core.
What is the core?
The central part of Earth below the mantle.
