Chapter 2 - Rocks and Minerals--A First Look

Chapter 2 - Rocks and Minerals--A First Look - Chapter 1 -...

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Chapter 1 - An Overview of Our Planetary Environment Environmental Geology  - study of the interactions between humans and  their geologic environment. Earth In Space And Time     o The Early Solar System     Most Astronomers accept some sort of "Big Bang" as the origin of today's  universe Stars formed from the debris of the Big Bang Our sun and its system of circling planets, including the earth, are  believed to have formed from a rotating cloud of gas and dust, some of it  from debris from older stars. The dust clumped into planets, the formation of which was  essentially complete over 4,500,000,000 years ago. o The Planets     The composition of plants formed depended largely on how near they  were to the hot sun. Planets formed nearest to the sun contained mainly metallic iron  and a few minerals with very high melting points, with little water or gas. Further out, planets incorporated much larger amounts of lower- temperature minerals, including some that contain water locked within their  crystal structures Made it possible for earth to have liquid water at it's  surface Farther from the sun, temperatures were so low that nearly all of  the materials in the original gas cloud condensed The result was a series of planets with a variety of  compositions, most quite different from the earth. o Earth, Then and Now     The early earth was heated by the impact of the colliding dust particles  and meteorites as they came together to form the earth, and by the energy  release from decay of the small amounts of several naturally radioactive  elements. These heat sources combined to raise the earth's internal temperature  enough that parts of it melted.   Metallic iron, would have tended to sink toward the middle of the  earth.  As cooling progressed, lighter, low-density materials crystallized and  floated out toward the surface.
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Core  - innermost zone of the earth; composed largely of  iron. Made up mostly of iron, with some nickel and a few  minor elements Mantle  - zone of the earth's interior between crust and  core; rich in ferromagnesian silicates. Made up mainly of iron, magnesium, silicon, and  oxygen combined in varying proportions in several different  minerals Crust  - outermost zone of earth; composed predominately  of relatively low-density silicate minerals Has everything The heating and subsequent differentiation of the early earth led to  another important result: formation of the atmosphere and oceans. Many minerals had contained water, and as the earth's surface 
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This note was uploaded on 04/16/2008 for the course GEO 105 taught by Professor Donahoe during the Spring '08 term at Alabama.

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Chapter 2 - Rocks and Minerals--A First Look - Chapter 1 -...

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