BITTER SPRINGS STAGE IN THE AMADEUS BASIN, CENTRAL
AUSTRALIA
Intervals
of relatively light carbon isotopes in the Neoproterozoic
are commonly associated with regional or global glaciation.
The first low d13C excursion in the Neoproterozoic, the
Bitter Springs Stage (~800 Ma), is an exception as it
precedes all the known Neoproterozoic glacial events. In
Svalbard, Maloof et al. (2006) observed that this interval
of relatively low d13C is bracketed by paleomagnetic
reorientations and transient changes in sea level. They
explain these coincidental changes by inferring rapid
shifts in paleogeography associated with a pair of true
polar wander (TPW) events. The possibility of TPW, in which
there is relative motion between the silicate Earth and the
spin vector of up to 90 degrees at rates that far exceed
those of normal plate tectonics, has been discussed and
shown to be a theoretic possibility for years in the
geophysical literature. Such an event would occur to keep
the earth in rotational balance during mass shifts within
the mantle.
The goal of the current research is to test the TPW
hypothesis by performing integrated physical, chemical and
magnetic stratigraphy on the carbonates of the Bitter
Springs Formation in the Amadeus Basin of Australia (where
the d13C interval was first observed).
Our group's research on the project is in collaboration
with Galen Halverson (University
of Adelaide) and
Matt Hurtgen (Northwestern
University).
Adam Maloof,
Catherine Rose and I
are returned to the field in 2007 and are currently
processing more samples from throughout the Bitter
Springs Formation.