Skip to Main Content
Book Chapter

Global modelling of continent formation and destruction through geological time and implications for CO2 drawdown in the Archaean Eon

By
Jan D. Kramers
Jan D. Kramers
Isotope Geology Group, Institute of Geological Sciences, University of Bern, Erlachstrasse 9a, 3012 Bern, Switzerland
Search for other works by this author on:
Published:
January 01, 2002

Abstract

The possible drawdown of a massive CO2 atmosphere in early Earth history is discussed using two working hypotheses: first, that this removal of CO2 from the atmosphere occurred mainly via silicate weathering; second, that crust-to-mantle recycling rates found from forward modelling of crust-mantle history can be used to estimate rates of this ancient silicate weathering. Previous U-Th-Pb and Sm-Nd forward modelling efforts are reviewed, from which it was concluded that an insignificant amount of continental crust existed at 4.4 Ga, i.e. so-called ‘no-growth models’ for the continental crust appear untenable. New modelling carried out is based on a crustal growth curve starting with zero mass at 4.2 Ga and reaching 75% of the present crust mass by 2 Ga. It concerns variations in crust-to-mantle recycling rates through geological time. Best fits to isotope data are obtained if it is assumed that erosion rates (mass removal per unit surface) were approximately constant from early Archaean time to the present. From the results it can be estimated that drawdown of a massive CO2 atmosphere by silicate weathering could have been completed by the end of Archaean time at the earliest, and about 1.5 Ga ago at the latest.

You do not currently have access to this article.

Figures & Tables

Contents

Geological Society, London, Special Publications

The Early Earth: Physical, Chemical and Biological Development

C. M. R. Fowler
C. M. R. Fowler
University of London, UK
Search for other works by this author on:
C. J. Ebinger
C. J. Ebinger
University of London, UK
Search for other works by this author on:
C. J. Hawkesworth
C. J. Hawkesworth
University of Bristol, UK
Search for other works by this author on:
Geological Society of London
Volume
199
ISBN electronic:
9781862394476
Publication date:
January 01, 2002

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal