Geo101.18.First4GA[1]

Geo101.18.First4GA[1] - 1 The frst 4 billion years Present...

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Unformatted text preview: 1 The frst 4 billion years Present composition oF Earths atmosphere during the frst 600 million years oF Earth History, what we call the Hadean Eon , the temperature oF the Earth increased with the accumulation oF planetesimals, molten iron began to sink to the center oF the core, leaving behind the shell oF rock we call the mantlewe reFer to this as the iron catastrophe the Hadean grew so hot that a magma ocean consisting oF ultramafc melt rock (rich in Mg and e) rose From the mantle and ooded the surFace oF the Earth The Hadean might have appeared like a magma ocean with small crusts oF solid basalt, with no permanent crust, no permanent oceans Outgassing oF the mantle the atmosphere during the Hadean was unbreathable, high NH 3 (ammonia) and in N 2 (nitrogen), CH 4 (methane), CO 2 (carbon dioxide), SO 2 (sulFur dioxide) and water vapors 2 As Earths differentiates, the upper part of the Earth outgassesand an atmosphere develops a N 2- CO 2 -sulfur rich atmosphere develops from gases released from volcanic eruptions. Earths early atmosphere was unbreathable, high NH 3 (ammonia) and in N 2 (nitrogen), CH 4 (methane), CO 2 (carbon dioxide), SO 2 (sulfur dioxide) and water vapors The early atmosphere and water intereact and the atmosphere begins to evolve. More to come one this As the surface of the Earth begins to cool, water vapors condense and water begin to accumulate. Has Earths Atmosphere evolved over the past 4.5 Ga? A closer look Composition of dry atmosphere, by volume ppmv: parts per million by volume Gas Volume N2 780,840 ppmv (78.084%) O2 209,460 ppmv (20.946%) Ar 9,340 ppmv (0.9340%) CO2 383 ppmv (0.0383%) Ne 18.18 ppmv (0.001818%) He 5.24 ppmv (0.000524%) CH4 1.745 ppmv (0.0001745%) Kr 1.14 ppmv (0.000114%) H2 0.55 ppmv (0.000055%) Not included in above dry atmosphere: H2O vapour ~0.25% over full atmosphere, typically 1% to 4% near surface Has Earths Atmosphere evolved over the past 4.5 Ga? 1) The First Atmosphere- Earth original atmosphere was primarily H and He. Heat from the still-molten crust , and the sun, plus a probably enhanced solar wind , dissipated this atmosphere. 3 Earths magnetosphere The Solar System is a dangerous place to live Large amounts of radiation (cosmic rays, solar wind) are present in interplanetary space On Earth, we are protected from these harmful cosmic rays by our atmosphere and magnetosphere. Earths magnetic Feld forces these cosmic rays to deect away from Earth. ormation of Earths moon Soon after the Earth forms, a small planet collides with it, blasting debris that forms a ring around the Earth. The Moon forms from the ring of debris....
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Geo101.18.First4GA[1] - 1 The frst 4 billion years Present...

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