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Unformatted text preview: Geology Exam 1 Outline LECTURE 1 Earth system science- the study of interactions within and between the various components of the earths system o Integration of all the natural sciences (biology, chemistry, physics) under one umbrella: geoscience The earth is the ultimate complex, dynamic system Three main systems o The climate system Cryosphere- ice caps Hydrosphere- oceans Biosphere- life Atmosphere- enveloping ball of gas and water o The plate tectonic system Asthenosphere Deep mantle Lithosphere o The Geodynamo system- earths magnetic field Inner Core Outer Core Composition of atmosphere? o Nitrogen 79% Greatest amount, primary o Oxygen 20% o Argon .9% o Carbon dioxide .036% Global warming, highly influences climate o Water vapor 4% o Methane (trace amounts) Where did these gases come from? o Gasses left over from forming of solar system, most of the atmosphere today comes from volcanic eruptions, most oxygen comes from plant respiration Why are these gases in the atmosphere? o Gravitational attraction keeps the gasses in the atmosphere The composition of the atmosphere has changed over the history of the Earth Atmospheric composition, shown by the relative concentration of various gases, has been greatly influenced by life on the earth. The early atmosphere had fairly high concentrations of water and carbon dioxide and, some experts believe, methane, ammonia and nitrogen. After the emergence of living organisms, the oxygen that is so vital to our survival became more plentiful. Today carbon dioxide, methane and water exist only in trace amounts in the atmosphere. Earths hydrosphere o What is its composition? Water Dissolved gases (oxygen, carbon dioxide, etc.) Salts and dissolved solids o Where did this stuff come from? A lot is erupted out as a result of volcanoes. A lot of it, however, is considered to have come in from comets as icy debris. o Has the composition or amount of water in the hydrosphere changed over the history of the Earth? It has remained pretty constant o How does the hydrosphere interact with other earth systems? The other systems would be very different o Distribution of Earths water 97.5% ocean Most of the worlds water is in the oceans Most of the worlds fresh water is frozen 69.6% of fresh water is frozen Distribution of Earths Unfrozen fresh water 98.7% groundwater .98% surface water .1% atmospheric o Earths biosphere What is its composition? The biosphere is varied, the majority of the planet is inhabited by bacteria (microbes) How long has life been on earth?...
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- Spring '05