THE EARTH

The structure of the Earth

• Earth’s surface is divided into:

– Litosphere (solid and rocky part of Earth)

– Hydrosphere (water: oceans, rivers, lakes…)

– Atmosphere (air: layer of gases)– Biosphere (places where life exists)

Geology:

the study of the materials that make up the solid part of the Earth.

Geological ages

SnowballEarth750 - 635 millions

PROTEROZOIC

Paleozoic Age: Cambrian sea (525 millions)

PALEOZOIC AGE540-251 mill.

PANGEA

Trilobites

Formation of continents

MESOZOIC AGE251-65 millions.

Dinosaurs

CENOZOIC AGE(65-2 mill.)

Rise of mountains

Age of mammals

Quaternary Age(2 millions onwards)

Rise of human beings.

The inner structure of the Earth

The inner structure of the Earth

How many kms. Each layer?

Continental drift

• 2. EARTH’S STRUCTURE (pages 26,27)

• Planet Earth has three layers:• The core: inner part of the Earth, made up mainly by

iron. – Inner core, extremely hot and solid because of pressure.– Outer core: extremely hot liquid.

• The mantle, made up by a hot liquid/plastic called magma.

• Magma sometimes pushed up to the surface and creates volcanic eruptions (this magma is called lava).

• The crust: solid, outer part of Earth surface, where we live.– Continental crust (30-70 km. deep)– Oceanic crust (10 km. deep).

PANGEA(200 millions ago)

• Continental drift and tectonic plates.

Continents move slowly over the mantle, like wood on water.

200 millions ago, a supercontinent, called Pangea started to separate and create the current continents in the present. This is called continental drift(1).

• Tectonic plates: Our continents are part of tectonic plates, that move continually. There are eight major plates and some more smaller. These plates collide each other or move apart.

• The movement of this tectonic plates is responsible of eruptions and earthquakes in the boundaries of the plates.

[1] Continental drift: deriva continental. Tectonic plates: places tectónicas. Earthquake: terremoto. Boundaries: limits.

How continents move?

Internal forces of relief• 1.- Pressures • 1.a.- Folds

SYNCLINE(fold downwards)

ANTICLINE(fold upwards)

FOLDS

QUARCITE FOLDS in Sierra de Fuentes(Cáceres)

QUARCITEFOLDS IN SIERRA DE FUENTES(CÁCERES)

SYNCLINE OF CÁCERES

Cáceres

Internal forces of relief• 1.b.- Faults

Internal forces: faults

Faults: breaks in rock layers

Tiny fault in a rock. Quartz layer.

Fault: Ronda norte (Cáceres)

Fault plane (espejo de falla)

Falla de San Andrés

Internal forces of relief

• 2.- Earthquakes

FAULT

EarthquakeConsequencesCalifornia

Earthquakes on the ocean: tsunamis

Japan, 2012

Seismograph

Internal forces of relief• 2.-Volcanoes

Internal forces of relief: volcanoes

LAVA FLOWS

CRATER

VOLCANICBOMBS

CONE

VOLCANOESUNDER THE SEA

(India)

VOLCANOESERUPTIONSCAN CREATENEW ISLANDS

(ICELAND)

External agents of relief

• 1.- Water• 2.- Wind• 3.- Changes of temperature• 4.- Human action

External forces of relief

• Erosion• Transportation• Deposition

EXTERNAL AGENTS (WATER, AIR), CHEMISTRYERODES THEROCK (GRANITE)

BARRUECOS(MALPARTIDA DE CÁCERES)

TRANSPORTATIONAND DEPOSITION(SEDIMENTS)

Rivers transportsLots of sediments

Other external agents

The ice.

Glacier

Icetongue

Icetongue

Cirque

Near Jerte

Andes argentinos

V- and u- shaped valleys

Other agents: Human action.

Alcántara old quarry (vieja cantera de Alcántara).