Forces of Change Why is the Earth not Flat?

Savage Earth What caused this?

Savage Earth What is this?

Savage Earth What caused this?

Savage Earth What caused this?

Let’s Review What is physical geography? The study of understanding the processes and patterns of the natural environment. In other words……how the earth works!!

Earth Systems Atmosphere – air and gasses Lithosphere – Earth’s surface and interior Biosphere – living things Hydrosphere – water (all forms)

Earth’s Interior Inner Core – Very hot very dense. Outer Core – Hot molten liquid. Mantle – Mix of liquid and solid. Crust – Thin solid top layer.

Plate Tectonics Has the Earth always looked the same? Observe an animation of the breakup of Pangaea.

Continental Drift The theory that the earth’s crust is divided into “plates” that slowly drift apart over time What “fits” together?

Plate Tectonics The study of plate movement and its consequences. There are 3 types of plate movement -Subduction -Spreading -Transformation

Subduction A geologic process in which one edge of one crustal plate is forced below the edge of another.

Spreading The process by which plates are moving apart and new crust is created by magma pushing up from the mantle

Transformation The process by which plates slide horizontally past one another.

Changing the face of nature Are these “constructive” forces the only ones at work on the Earth? Imagine the world if only these forces existed…

Destructive Forces There are 3 types of “destructive” forces: -Erosion -Weathering -Deposition

Erosion the process by which the surface of the earth is worn away by the action of water, wind, waves, glaciers

Weathering the various mechanical and chemical processes that cause exposed rock to decompose. Mechanical Weathering caused by windblown particles Chemical Weathering caused by acid rain

Deposition The process of accumulating or laying down of matter by a natural process. Alluvial fan after a flash flood Mississippi river delta