| Autor: |
Novoselov AA; University of Campinas, Institute of Geosciences, Campinas, 13083-970, Brazil. Alexey.Novoselov@udec.cl.; University of Concepción, Institute of Applied Economic Geology, Concepción, Casilla 160-C, Chile. Alexey.Novoselov@udec.cl., Silva D; University of Campinas, Institute of Geosciences, Campinas, 13083-970, Brazil., Schneider J; University of Campinas, School of Civil Engineering, Architecture and Urban Design, Campinas, 13083-889, Brazil., Abrevaya XC; Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, C1428EHA, Argentina.; CONICET-Universidad de Buenos Aires, Instituto de Astronomía y Física del Espacio (IAFE), Buenos Aires, C1428ZAA, Argentina., Chaffin MS; University of Colorado, Boulder, 80302, USA., Serrano P; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, 14473, Germany., Navarro MS; University of Campinas, Institute of Geosciences, Campinas, 13083-970, Brazil., Conti MJ; André Tosello Institute, Campinas, 13087-010, Brazil., Souza Filho CR; University of Campinas, Institute of Geosciences, Campinas, 13083-970, Brazil. |
| Abstrakt: |
The environmental conditions on the Earth before 4 billion years ago are highly uncertain, largely because of the lack of a substantial rock record from this period. During this time interval, known as the Hadean, the young planet transformed from an uninhabited world to the one capable of supporting, and inhabited by the first living cells. These cells formed in a fluid environment they could not at first control, with homeostatic mechanisms developing only later. It is therefore possible that present-day organisms retain some record of the primordial fluid in which the first cells formed. Here we present new data on the elemental compositions and mineral fingerprints of both Bacteria and Archaea, using these data to constrain the environment in which life formed. The cradle solution that produced this elemental signature was saturated in barite, sphene, chalcedony, apatite, and clay minerals. The presence of these minerals, as well as other chemical features, suggests that the cradle environment of life may have been a weathering fluid interacting with dry-land silicate rocks. The specific mineral assemblage provides evidence for a moderate Hadean climate with dry and wet seasons and a lower atmospheric abundance of CO 2 than is present today. |
