New constraints on Archean Atmosphere

A recent study about Archean Atmosphere is published today in Science. This study involving Pascal Philippot from IPGP was performed on rocks drilled by IPGP in Australia in 2004.

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Article at a glance

The first life on Earth blossomed up during the Archean, between 3.8 and 2.4

billion years ago, at a time when climatic conditions were made favourable

by the absence of any major glaciations. Researchers at the CRPGCNRS

University of Lorraine (France), in collaboration with the University

of Manchester (UK) and the Institut de Physique du Globe of Paris, have

measured the pressure of nitrogen (N2, which forms 78 % of the present-day

atmosphere) and the isotopic composition (15N/14N ) of this element in the

Archean atmosphere by analyzing water bubbles trapped in rocks formed

near the surface of the Earth 3.5 billion years. These measurements provide

important clues to reconstruct ancient climatic conditions, including the level

of ancient atmospheric carbon dioxide (CO2), a major greenhouse gas in the

atmosphere, as well as the strength of the Earth’s magnetic field at that time.