Geoscience Reference
In-Depth Information
Huronian Supergroup
Diamictite
Sandstone
Carbonate
Argillite
2.217 Ga
Bar River
Gordon Lake
No MIF-S
Lorrain
Redbeds
Gowanda
Serpent
No MIF-S
Espanola
Bruce
Mississagi
MIF-S
Pecors
Ramsey Lake
McKim
Matinenda
Detrital
uraninite
& pyrite
2.45 Ga
Figure 8.1. general stratigraphy of the Huronian supergroup. major events in the history of
earth-surface oxygenation are also shown. note that oxygen indicators suggest the gOe
(great oxidation event) occurred after the second glacial event (as represented by the Bruce
diamictite; a diamictite is a glacial deposit). the mIF-s signal refers to the mass indepen-
dent sulfur isotope signal, as discussed in
chapter 7.
Figure borrowed from sekine et al.
(2011) with slight modification. reproduced with permission.
This is also a great story, but one difficulty with the evidence com-
piled by Cloud and Holland is that rocks containing detrital uraninites
and pyrites, as well as those with continental red beds, are not contin-
uously represented in the geologic record. Therefore, our resolution of
the timing of the GOE from these indicators is rather poor. There is,
however, another approach which will let us much more precisely ex-
plore the timing of the GOE. To follow this idea, we return to James
