20_globalchange_09_post

20_globalchange_09_post - bal Change: bal Change: 1 20:...

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Unformatted text preview: bal Change: bal Change: 1 20: Global Change bal Change: bal Change: 2 Global Change: Definitions Earth system : global interactions of the lithosphere, hydrosphere, atmosphere, and biosphere Global change : modifications in the Earth system Gradual change : modifications that take place over millions or billions of years Catastrophic change : modifications that take place instantaneously (geologically speaking) Unidirectional change : modifications that never repeat Cyclic change : modifications that repeat bal Change: bal Change: 3 Origin of solar system Nebula : cloud of gas or dust in space. Nebula theory of planet formation : gravity and collisions within a nebula cause the formation of a central sun and orbiting planets. Plate, p. 26-27 bal Change: bal Change: 4 Hadean: Hell on Earth Lava ocean--produced by heat from Fig. 13.4 Differentiation Differentiation : dense material sinks, light : dense material sinks, light material rises; forms concentric shells material rises; forms concentric shells Fig. 23.3 4600-3800 mya bal Change: bal Change: 5 Role of volcanic outgassing Role of volcanic outgassing Composition of early atmosphere: methane (CH Composition of early atmosphere: methane (CH 4 ), H ), H 2 O, O, ammonia (NH ammonia (NH 3 ), H ), H 2 S, CO S, CO 2 Archean formation of atmosphere & oceans 3800-1600 mya bal Change: bal Change: 6 Subduction --> island arcs; collisions --> early continents Archean: formation of crust Fig. 13.5 bal Change: bal Change: 7 Archean: formation of crust Continental crust cannot be subducted; continents grow in size through time Fig. 13.6 Fig. 13.10 1.1 1.1 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 >2.5 >2.5 >2.5 >2.5 1.9 1.9 1.8 1.8 1.8 1.8 1.6-1.7 1.6-1.7 Older core (craton) surrounded by Older core (craton) surrounded by younger rocks; younger rocks; ages ages are in billions are in billions of years of years bal Change: bal Change: 8 Archean: first life Fig. 13.7 Bacteria in 3.2 billion-year-old chert Bacteria in 3.2 billion-year-old chert from South America from South America bal Change: bal Change: 9 Proterozoic: atmosphere Role of life Role of life Banded iron formations (BIFs) Fe dissolved in the Banded iron formations (BIFs) Fe dissolved in the ocean reacted with O ocean reacted with O 2 , forming worldwide FeO deposits. , forming worldwide FeO deposits. Fig. 13.12 Fig. 13.13 bal Change: bal Change: 10 10 Supercontinental cycle : smaller continents coalesce to form a supercontinent, which then rifts and breaks apart, only to recombine as oceanic crust created during seafloor spreading is subducted Paleozoic: tectonics Fig. 23.5 bal Change: bal Change: 11 11 Appalachian orogeny : record of assembly of Pangea in eastern North America due to subduction and...
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This note was uploaded on 09/25/2011 for the course GEOLOGY 100 taught by Professor Lepre during the Fall '11 term at Rutgers.

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20_globalchange_09_post - bal Change: bal Change: 1 20:...

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