Geology, Continental Drift, and Earth/Space Science

Geology and Continental Drift

Crust

● The part we live on.

● Broken into many plates

that “float” on the mantle.

Lithosphere

● The crust and upper

mantle make up this zone

of brittle rock.

Mantle

● The largest layer that is

composed of very hot,

dense rock.

● The reason the plates

moves (convection

currents)

Outer Core and Inner Core

● Composed of liquid metals

with extreme heat and

pressure

Plate Tectonic Theory

• Earth’s crust is broken into pieces called plates

• These plates are part of the lithosphere and “float”

on the mantle.

• Movement results in volcanic eruptions, mountain

building, earthquakes and ocean basins.

3 Different Ways the Plates Move

● Convergent - moves together

● Divergent - moves away

● Transform - slides past

Convergent Boundary

Plates move towards

each other

(collide)

A continental plate collides with a oceanic plate

● Subduction occurs

● Trenches form

● Volcanoes form

● Strong Earthquakes

Two continental plates collide

● Mountains form

Divergent Boundary

Plates move away

from each other

(pull apart)

Oceanic plates move apart

● The lithosphere lifts and produces a mid-

ocean ridge.

● The crack allows magma to rise, cool and

become new crust.

Continental plates move apart

● A rift is created

● Earthquakes can occur

● New ocean basin can form due

to sinking of the mid plate

Transform Boundary

● Earthquakes are created from stress released

when the plates slide along each other.

● Fault line is where the plates slide past each

other.

● Crust is neither created nor destroyed.

Earth/Space Science

What evidence do we have that Earth has evolved over time?

● Natural processes such as weathering, erosion, and plate tectonics

have reshaped Earth’s surface. The distribution of land and water

on Earth’s surface has changed over time.

● Geologists use the following methods to determine the age of

Earth:

○ Fossils

○ Relative and Absolute Dating

○ Earth’s Surface Features

○ Radioactive Dating

○ Geologic Time Scale

Relative dating

● Examines if one layer

of rock is older than

another.

● It is approximate

Absolute Dating

• Uses radioactive material in igneous and metamorphic rock to determine the age of rocks in years.

Law of Superposition

● oldest layers are on

the bottom and as

you move towards

the surface the

rocks are younger.

Fossils are

● preserved remains of living things

● most often found in sedimentary rock

They provide evidence

● about the history of life and past environments

on Earth.

● how different groups of organisms have changed

over time.

The Geologic Time Scale

● a calendar created by scientists for

“events” in Earth’s history

● divided into different units of time

● fossils that form in the layers or strata of

rock is the way that they establish this

time scale.

Radioactive Dating

Scientists use Radioactive Dating to determine age of rocks.

● Radioactive elements decay or breakdown in rock (igneous or metamorphic) and become unstable.

● The quantity of unstable atoms in the rock is measured and compared to quantity of stable atoms still in the rock to estimate the amount of time that has passed since the rock formed.

These is how the age of rock in years is determined for Absolute Dating

Hierarchical Relationships in Space

The order in which objects in space are organized according to size (largest to smallest)

Universe, Galaxies, Solar System, Stars, Planets, and Comets, Asteroids, and Meteors.

Universe

The universe is space and all the matter and energy in it.

Throughout the universe, there are areas where galaxies are

densely concentrated.

These areas are called clusters and superclusters.

The universe also contains huge spherical areas where very

little matter exists.

They are called voids.

Galaxy

Galaxies are large scale groups of stars that are bound

together by gravity.

Size of a typical galaxy is 100,000 light years in diameter.

Roughly 100 billion stars are contained within a galaxy.

** Galaxies are moving away from each other as space

expands

Solar System

The solar system is the collection of large and small

bodies that orbit a central star.

Altogether, there can be up to a trillion small bodies

in a solar system.

Stars

A star is a large celestial body that is composed of

gas and emits light.

Most stars are composed almost entirely of

hydrogen and helium.

Planets

A planet is a spherical body that orbits a

star.

The sun is our central star in our solar system

Comets, Meteors, Asteroids

Asteroids and Comets are large fragments that orbit the sun.

Meteors are known as a “shooting star”

Asteroids = rocky

Comets = mix of frozen gases, water, and dust particles

Meteors = made of rock and metal

Asteroids are mostly located in Asteroid Belt between Mars and

Jupiter

Comets sometimes return; others have a single revolution.

Distances in Space

An astronomical unit (AU) measures the

average distance between the Sun and

another object in the solar system. It is used

only when you measure distances within the

solar system.

A light-year is the distance light travels in

one year, hence the name "light-year". It is

used to measure the distances between

galaxies and stars.