Interior of the Earth Lecture #3

Surface 71% water 29% dry land

Formation of Earth ~4.6 billion years ago Earth melted Gravity compressed matter into a smaller volume Earth melted Radioactivity Energy of particle motion transformed into heat Iron falls toward interior displacing lighter materials Meteor impacts Energy of motion –> heat Collisions with left over material from solar system formation collide with earth. Earth heats up and liquefies. Liquid settles out into layers by density. Meteor impact formed Moon

Earth’s Layers Convection causes cooling Settle into 3 layers Cooled earth off rapidly Heavy Fe and Ni sank due to gravity Low density molten materials rose Settle into 3 layers Crust Mantle Core Layer’s classified by density of rock.

Crust 10 – 100 km thick 1% of Earth’s volume 1% of Earth’s mass

Crust 2 Types of crust Oceanic Continental dense rock young less dense rock old

Mantle About 3000 km thick 80% of Earth’s volume 66% of Earth’s mass Consists of solid rock Top flows like molasses. Caused by High pressure/temperature

Core About 3500 km thick 19% of Earth’s volume. 33% of Earth’s mass. Very dense 90% iron and 10% nickel 2 Parts Outer Core Iron and nickel in a liquid state. Inner Core Solid iron and nickel

Crust/Mantle Interaction Lithosphere (C/M) Solid Floats on asthenosphere. Asthenosphere (M) molasses Mesosphere (M) Stiffer rock

Words of Wisdom