of Richard Bakker
Down Under & Timor on Top:
rates of Earth's youngest orogen
|The islands which make
up the Banda Arc, SE Asia are the result of back arc volcanism. However,
one of the islands, Timor is not. The island is the result of the continental
margin of Australia entering the subduction zone. Timor is therefore offers
a unique opportunity to study the early stages of orogeny.
Geological map, from Harris, 2006.
has carried out fieldwork in the country of East Timor, together with Garrett
Tate (PhD student) and Nadine
McQuarrie (both Princeton University), professor Ron
Harris (Brigham Young University) and Douwe
van Hinsbergen (PGP, University of Oslo). On Timor Pliocene basins
are present which have preserved the uplift history.
drilling in the river
The results will be
used as a constraint to model the uplift. Different scenarios will be tested
to explain the rapid uplift of the island of Timor. Richard's project will
be supervised by Douwe van
Hinsbergen, Wout Krijgsman and Jan-Willem
|The surface geology
of the island of Timor mainly consists of duplexes of Australian shelf
stratigraphy. Detailed mapping of these duplexes has been carried out by
Garrett Tate, Nadine McQuarrie, Richard Bakker and others. Using paleomagnetism,
a study will be conducted to find out if there is vertical axis rotation
between the horses. The quantification of these relative rotations will
provide a better estimate for the shortening factor between the Banda Arc
units and the Australian shelf units.
Typical outcrop of the Aitutu Limestone formation. Right: Mario Amaral
(Universitas Teknologi Yogyakarta) drilling cores from this formation.
The results may
provide a test for the hypothesis of True Polar Wander.
van Hinsbergen drilling.
of the Australian shelf formations is the Maubisse Limestone. This formation
has a very abundant fossil record. This indicates a shallow marine, warm
environment. The Maubisse formation is the time equivalent of the Permian.
During the Permian the Indo-Australian plate was situated on the south
pole. A paleomagnetic study is carried out to determine the paleolatitude
of the Maubisse Limestone formation.
Typical outcrop of the Maubisse Limestone formation. Right:
Crionid fossil, compass for scale.
Publications of Richard Bakker
McQuarrie, N, Bakker, R.R., van Hinsbergen, D.J.J., and Harris, R.A. (2010).
Active Arc-Continent Accretion in Timor-Leste: New Structural mapping and
quantification of Continental Subduction. Abstract T51A1996T
presented at 2010 Fall Meeting, AGU, San Francisco, Calif., 13-17 Dec.