Geoscience Reference
In-Depth Information
40
Berner (2006)
30
O
2
%
20
10
Bergman et al (2004)
0
0
100
200
300
400
500
600
Time (million years ago)
Figure 11.4. results from Berner's geOCArBsUlF model compared to the COPse
model of Bergman and others. the grey area around the results from Berner's model
encompasses the range of uncertainty as estimated by Berner, as well as newer results
presented as refinements of the original geOCArBsUlF model.
oxygen modeling based on the isotope records of carbon and sulfur.
This model is called GEOCARBSULF, and it is a grand model of the
histories of both atmospheric CO
2
and O
2
. The oxygen model results are
presented in
igure 11.4,
and these are very similar to our earlier model
results (compare to
ig. 11.3)
, reinforcing the idea that the rock abun-
dance and isotope data give a similar picture of the processes control-
ling oxygen liberation to the atmosphere.
But this isn't the end of the story. Tim Lenton from the University of
Exeter, his thesis advisor Andy Watson from the University of East An-
glia, and their PhD student Noam Bergman also attempted to model
atmospheric oxygen (and CO
2
) through Phanerozoic time, but with a
somewhat different approach. Their so-called COPSE (Carbon-Oxygen-
Phosphorus-Sulfur-Evolution) model is rooted in the philosophy of the
