EARTH COMPOSITION & STRUCTURE

A. INTRODUCTION

Internally and externally driven processes

Processes that build the landscape up and that wear the landscape down

B. LEARNING OUTCOMES

By the end of this unit you should be able to:

classify rocks based on their formation and their composition (primary or secondary minerals, felsic or mafic minerals);

describe the major layers to the earth defined by composition and those defined by behavior, and compare and contrast continental crust to oceanic crust; and

identify the large-scale landforms of the earth, describe their geographic distribution, and locate them on a map.

C. COMPOSITION OF THE EARTH

Minerals

Image credit: K.A. Lemke. Used with permission.

Rocks

Image credit: K.A. Lemke. Used with permission.

Rock Cycle

Image credit: K.A. Lemke. Used with permission.

D. STRUCTURE OF THE EARTH

Layers based on composition:

Crust

Mantle

Upper

Lower

Core

Layers based on behavior:

Lithosphere

Asthenosphere

Mesosphere (lower mantle)

Outer Core

Inner Core

Image credit: K.A. Lemke. Used with permission.

Image credit: K.A. Lemke. Used with permission.

E. LARGE SCALE FEATURES

First Order Features

Image credit: Marine Geology & Geophysics, NOAA National Geophysical Data Center. Globe: A Gallery of High Resolution Images. 10 arc-minute grid with GLOBE elevations & bathymetry from Smith & Sandwell. http://www.ngdc.noaa.gov/mgg/topo/globega2.html

Second Order Features

continental shields

continental platforms

orogenic belts

continental shelves

ocean basins & abyssal plains

mid-oceanic ridges

deep ocean trenches

volcanic arcs

F. SUMMARY

Driving framework: set of forces trying to change the landscape

may be internally or externally driven

may build the landscape up or wear it down

Resisting framework: characteristics of the landscape that resist change

minerals & rocks, and the structure of the earth

Driving & resisting forces interact to create large scale landforms