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Waiting for O (sub 2)

Kevin Zahnle and David Catling
Waiting for O (sub 2) (in Earth's early atmosphere and surface environment, George H. Shaw (editor))
Special Paper - Geological Society of America (May 2014) 504: 37-48


Oxygenic photosynthesis appears to be necessary for an oxygen-rich atmosphere like Earth's. However, available geological and geochemical evidence suggests that at least 200 m.y., and possibly as many as 700 m.y., elapsed between the advent of oxygenic photosynthesis and the establishment of an oxygen atmosphere. The interregnum implies that at least one other necessary condition for O (sub 2) needed to be met. Here, we argue that the second condition was the oxidation of the surface and crust to the point where free O (sub 2) became more stable than competing reduced gases such as CH (sub 4) , and that the cause of Earth's surface oxidation was the same cause as it is for other planets with oxidized surfaces: hydrogen escape to space. The duration of the interregnum was determined by the rate of hydrogen escape and by the size of the reduced reservoir that needed to be oxidized before O (sub 2) became favored. We speculate that hydrogen escape determined the history of continental growth, and we are confident that hydrogen escape provided a progressive bias to biological evolution.

ISSN: 0072-1077
EISSN: 2331-219X
Serial Title: Special Paper - Geological Society of America
Serial Volume: 504
Title: Waiting for O (sub 2)
Title: Earth's early atmosphere and surface environment
Author(s): Zahnle, KevinCatling, David
Author(s): Shaw, George H.editor
Affiliation: NASA, Ames Research Center, Moffett Field, CA, United States
Affiliation: Union College, Geology Department, Schenectady, NY, United States
Pages: 37-48
Published: 201405
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 98
Accession Number: 2014-039301
Categories: Solid-earth geophysicsGeneral geochemistry
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
Secondary Affiliation: University of Washington, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201424
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