Brendan Duffy - PhD Summary
This research investigates feedbacks and linkages between the geodynamic
evolution of East Timor and the paleoceanographic development of the
Indonesian Throughflow (ITF), a group of currents that transfers water from
the western Pacific Ocean to the Eastern Indian Ocean via the Indonesian
Archipelago.
The island of Timor in the Banda Arc emerged from the seas in a critical
location and at a critical time in the development of the ITF, a small but
influential component of the oceanic circulation. Timor's location, Pliocene
emergence and subsequent uplift makes it an ideal archive of data on the
tectonic and oceanographic development of the ITF, particularly a proposed
switch in source waters from warmer to cooler waters. Such an oceanographic
change, which is theorised to have been caused by re-routing of the ITF's
Pacific source waters due to the collision of Papua New Guinea with Asia,
would have greatly impacted global climate and hominid evolution in the last
3-4 million years.
The geodynamic mechanism of uplift of Timor is of just as much interest as
is its paleoceanographic evolution. Recent geophysical surveys have
suggested an alternative, rebound, model for the uplift of Timor that stands
in contrast to previous compressional models and must impact any tectonic
models for the development of the Banda Sea region. The rebound hypothesis,
which also has implications for the bathymetric development of the ITF,
suggests that Timor's elevation stems from rebound of low density
lithosphere above a rupturing subduction slab.