Skip to Main Content
Book Chapter

Evidence and arguments for methane and ammonia in Earth's earliest atmosphere and an organic compound–rich early ocean

By
George H. Shaw
George H. Shaw
Geology Department, Union College, Schenectady, New York 12308, USA
Search for other works by this author on:
Published:
May 01, 2014

The preponderance of geologic evidence does not support carbon dioxide as the main carbon species degassed from early Earth, nor a carbon dioxide–rich early atmosphere. In fact, there are several problems that cannot be addressed by assuming either of these facets of what has become conventional wisdom about the early atmosphere. A careful examination of the conditions that most likely accompanied late accretion, incorporating the most probable average composition of accreting materials, suggests an early atmosphere produced by degassing of reduced carbon and nitrogen species, followed by photochemical processing to yield a surface environment rich in organic compounds. Recycling of these organics through hydrothermal and volcanic systems would have maintained a level of reduced gases (photochemically unstable as they may be) in the early atmosphere for an extended period, accompanied by a growing carbon dioxide component derived from mantle magmatism. Such a model for the early atmosphere is not only consistent with geological data, it also solves many problems of the early history of Earth.

You do not currently have access to this article.

Figures & Tables

Contents

GSA Special Papers

Earth's Early Atmosphere and Surface Environment

George H. Shaw
George H. Shaw
Geology Department, Union College, Schenectady, New York 12308, USA
Search for other works by this author on:
Geological Society of America
Volume
504
ISBN print:
9780813725048
Publication date:
May 01, 2014

References

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal