Early Earth

The range of conditions and compositions that have been proposed for Earth's early surface and atmosphere is considerable, from highly reducing and rich in organic compounds to essentially as oxidizing as today. Investigations have been guided by geological evidence, cosmochemical analysis, and comparisons to other terrestrial bodies. This new Special Paper from The Geological Society of America, edited by George H. Shaw of Union College, presents and discusses several, sometimes contradictory, models for early Earth.

Uniquely compiled as a collection of papers first presented at a Pardee Symposium at the 2011 GSA Annual Meeting, the book's primary chapters are accompanied by a commentary and followed by a transcript of the ensuing discussion at the meeting. An interpretive chapter discusses the material presented at the symposium and summarizes at least one perspective of the current status of the field.

As for the substance of the topic discussed, Shaw notes that "an extremely broad range of viewpoints is held by geologists, geochemists, atmospheric chemists, climate scientists, and various others, and informed by their own perspectives and the data they feel are most critical to the discussion." He writes that "In some cases, there are disparate inferences and conclusions drawn from more or less the same basic data. While this may seem surprising, it is, perhaps, a consequence of the nature of such an ancient and often skimpy geologic record."

In a summary of this 13-chapter book, Shaw writes humbly, "Although it is unlikely that all … of the views presented can be correct, there appears to be at least some possibility that some … fraction … may have some validity in forming a picture of an important period of Earth's history, one in which it is highly probable that life began its long journey."

More information:
rock.geosociety.org/Store/detail.aspx?id=SPE504

Provided by Geological Society of America