Dynamic EarthEarth Systems, Plate tectonics, Layers, Earthquakes, Valcanoes

Earth as a System Four parts:

Geosphere (rock) Mostly located in Earth’s interior

Atmosphere (air) Hydrosphere (water)

Oceans ¾ of the globe Biosphere (living)

Layers of the Earth Crust, Mantle, Core Lithosphere

the crust and the upper mantle Divided into plate tectonics

Asthenosphere Plastic, solid layer of mantle made of rock Allows tectonic plates to move on top of it (slow)

Mesosphere Lower layer of the mantle between the

asthenosphere and outer core

Continued… Outer Core

Dense, liquid layer Outer shell of core made up of liquid iron

and nickel Inner Core

Sphere of solid nickel and iron at center of the Earth

Earth’s inner and outer core make up about 1/3 of earth’s mass

Plate Tectonics Continental Drift

Fossil Evidence of the same kinds of animals living on separate continents.

The types of rocks found on each continent today show similar strata and ages. Mt. Ranges on the coast of West Africa disappear then suddenly reappear again on the coast

225 Million years ago

150 million years ago…

90 million years ago…

35 million years ago…

Present…

Plate Movements Divergent:

Sea Floor spreading: where new land is created. Occurs in the ocean (mid-ocean ridges)

Transform: As 2 plates slide past one another friction

builds. (Earthquakes) Convergent:

Plate collisions Subduction: plates push up continental plates

(Volcanoes) Uplift: Mountains form

Plate Movements

Convection Currents Occurs in the magma Magma is heated, becomes less dense

and rises, then cools, more dense and sinks

Heating, cooling (rising, sinking) creates currents = plate movement

Earthquakes

Divergent Plates

Volcanoes: Ring of Fire

Volcanoes Shield:

Large, broad with a crater at the top Slow eruption and lava oozes Examples: Mauna Loa in Hawaii and Mount

Wrangell in Alaska Composite:

Tall, steep, symmetrical (explosive, hard to predict

Examples: Mount Hood in Oregon, Mount St. Helens in Washington (many of these all over the world

… Cinder Cone

Lava in the form of cinders Most common type Examples: Mount Mazama in Oregon (Crater

Lake) Hot Spot: magma emerges from Earth but

not at plate boundaries (middle of plates) Examples: Hawaiian Islands, Galapagos,

Iceland, Yellowstone

Effects of Volcanoes Release of CO2, CO, He, H2, HF

(poisonous), SO2 (acid rain, pollution), HCl (irritant, acid rain)

Ozone depletion, global warming, haze effect (smog)

Not long term but combined with human activities they can be