Atmosphere ch 17 - TheAtmosphere...

Info iconThis preview shows pages 1–14. Sign up to view the full content.

View Full Document Right Arrow Icon
The Atmosphere
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The first atmospheres – 4.6 to 4.0 bya Continuous rain for almost 800 millions years Carbonate and carbon objects form CO2 Ice melted to water  Comet tails – frozen ammonia –forms nitrogen  
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
When life began – 4.0 to 2.6 bya Outgassing – escaped from mantle through volcanic  eruptions volatiles dissolved in magma that evoke on eruption Hadean Eon gas models linked to core formation and mantle  composition Miller-Urey experiment – on premise that early atmosphere  was CH 4 , NH 4 , H 2 , H 2 O, formed amino acids under  “primitive” conditions Premise has been called into doubt – most now believe  Hadean atmosphere was CO 2 , N 2 , H 2 O
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
Studies of ancient rocks show that the early  atmosphere was oxygen poor Photosynthesis –process by which organisms  2  to organic sugars, releasing O 2   as a by-product Cyanobacteria – simple, blue-green algae First Great Oxidation Event – 2.4bya oxygen began  to accumulate in the atmosphere
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
System interactions affecting the Hadean  atmosphere Geosphere-atmosphere interaction O 2  dissolves in water, as does Fe When Fe is present, O reacts to form solid iron oxides Without much O 2 , early dissolved Fe was high As O 2  levels rose, FeO came out in layers as banded iron  formations (BIFs) 90% of Fe used comes from BIFs, formed 2.6 to 1.9 billion  years ago
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 10
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Mesabi Range, northern Minnesota 
Background image of page 12
System interactions affecting the Hadean  atmosphere Biosphere – atmosphere interactions Early on H 2  + O 2  produced water, removing H 2 Later, bacteria removed H
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 14
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/15/2011 for the course ESC 1000 taught by Professor Staff during the Fall '08 term at University of Florida.

Page1 / 46

Atmosphere ch 17 - TheAtmosphere...

This preview shows document pages 1 - 14. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online