PUBLIC LECTURE ANNOUNCEMENT
MINERALS, METALS AND MATERIALS TECHNOLOGY CENTRE (M3TC)
FACULTY OF ENGINEERING
National University of Singapore
EA-06-15, 9 Engineering Drive1 Singapore 117576
Tel: (65) 6516 8296 Fax: (65) 6777 6235
TOPIC
SE Asian reconstructions, plate tectonics and crustal flow
SPEAKER
Prof Robert Hall
SE Asia Research Group, Department of Earth Sciences, Royal
Holloway University of London
CHAIRED BY
Prof Arun Mujumdar (Director M3TC)
DATE
14th May 2010
TIME
11am to 12.00pm
VENUE
EA-06-04, Faculty of Engineering, National University of Singapore
NUS Campus Map & NUS: Faculty of Engineering
Please register via email: m3tc@nus.edu.sg
SYNOPSIS
SE Asia is an unusual region. Plate tectonics provides a first order description of the region’s history but
only part of its explanation. Reconstructions are a framework for modelling the region but do not explain
Cenozoic deformation, essentially because most of SE Asia is not a rigid plate, nor can it be described as
multiple rigid microplates bounded by lithospheric faults. Nonetheless, a plate model does highlight where
and why things are different, and when events occurred.
Sibumasu and East Malaya–Indochina collision formed a Sundaland continent in the Early Mesozoic and
other fragments were added during the Cretaceous. Continental blocks rifted from Australia during the
Late Jurassic and Early Cretaceous are now in Borneo, Java and Sulawesi, not West Burma or Sumatra.
Their arrival terminated subduction beneath Sundaland at about 90 Ma and contributed to emergence of
an extensive landmass. At 45 Ma Australia began to move rapidly north, subduction resumed, and began a
complex pattern of subsidence and uplift within Sundaland. In the Early Miocene, from about 23 Ma, the
Sula Spur promontory collided with the Sundaland margin in east Indonesia. From 15 Ma there was
subduction hinge rollback into the Banda oceanic embayment, major extension, and later collision of the
Banda volcanic arc with the southern margin of the embayment.
Geological models developed in other parts of the world, in completely different tectonic settings, are
misleading. Rates of change are greater than expected. Plate movements and subduction have driven
change, but there has been delamination of crust from mantle lithosphere, and flow within the crust. The
history of Sundaland means it has a complex internal structure, with strong and weak parts. Overall, it has
a weak thin lithosphere, highly responsive to plate boundary forces. It was not a rigid plate and from
Borneo eastwards is really a wide plate boundary zone between a broadly weak continental region and
surrounding strong plates. A common feature of the region is synchronous rapid uplift of mountains close
to areas of major subsidence and very significant changes in relief in the last 10 Ma. High rates of erosion,
and massive movements of sediment have characterised the region.
The heterogeneous character of the Sundaland continent and shape of the Australian margin influenced
the way in which different parts of the region responded to plate tectonic forces. Extension due to
subduction rollback and arc–continent collision have contributed to vertical movements. In weaker areas,
the upper crust appears to be deforming almost independently of the deeper lithosphere and there have
been exceptionally high rates of vertical movements, both up and down. A hot weak deep crust has flowed
in response to tectonic forces, topographic forces and sedimentary loading.
About the
Speaker
Robert Hall is Professor of Geology and Director of the SE Asia Research Group at Royal Holloway
University of London. He completed his PhD in 1974 on ophiolites and sutures in eastern Turkey and later
worked in the Eastern Mediterranean and Middle East for several years. Since 1984 he has worked in SE
Asia, mainly in Indonesia, carrying out field-based research supported mainly by industrial consortia with
postgraduate research students and post-doctoral researchers. These studies have been the basis for
computer animated plate tectonic reconstructions of SE Asia and the SW Pacific for the Cenozoic. His
research interests are the regional geology of SE Asia and the western Pacific; island arc origin and
evolution; plate tectonic reconstructions; seismic tomography, mantle processes and tectonics of the
region; tropical sedimentation and links to provenance, climate and tectonics; the implications of plate
tectonics for the biogeography of SE Asia. Current SE Asia Research Group projects are in Borneo, Java,
Sulawesi and the Banda Arc, and Malaysia. Robert Hall is a Fellow and Chartered Geologist of the
Geological Society of London, a member of the Geological Society of America, the American Geophysical
Union, the Indonesian Petroleum Association, the SE Asia Petroleum Exploration Society and the Petroleum
Exploration Society of Australia.
Prof Robert Hall Curriculum Vitae.
All Are Welcome. Admission is Free
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