Current Research Projects

Dr. Anya Reading collecting a rock sample for cosmogenic nuclide analysis at Komsomolskiy Peak, the furthest southern outcrop of rock in the Australian Antarctic Territory during the 2002/2003 summer season. (Photo: M. Woolridge)

Looking back to see the future: Change in the Lambert Glacier and the East Antarctic Ice Sheet

Collaborators:
Professor Kurt Lambeck, RSES, ANU
Dr. Paul Tregoning, RSES, ANU
Dr. Richard Coleman, Geography and Environmental Studies, University of Tasmania
Dr. David Fink, Australian Nuclear Science and Technology Organisation

To develop a comprehensive understanding of the Lambert Glacier of East Antarctica, from the time of the last maximum glaciation to the present, through an integrated and interdisciplinary study combining new field evidence - ice retreat history, geodetic measurements of crustal rebound, satellite measurements of present ice heights and changes therein - with other geological and glaciological data and numerical geophysical modelling advances. The project contributes to the quantitative characterisation of the complex interactions between ice-sheets, oceans and solid earth within the climate system. Outcomes have implications for geophysics, glaciology, geomorphology, climate, and past and future sea-level change.

Erratic on relic surface, northern Sweden

Glacial landscape, northern Sweden

Glacial evolution of the Swedish Mountains: Cosmogenic nuclide constraints on landscape change.

Collaborators:
Professor Jon Harbor, Purdue University, U.S.A. and PRIME Lab, Purdue University, U.S.A.
Dr. Arjen Stroeven, Stockholm University, Sweden
Dr. David Fink, Australian Nuclear Science and Technology Organisation

We are applying cosmogenic nuclide dating to a range of glacial geomorphology and glacial chronology issues of landscape change in the northern Swedish Mountains. Be-10 and Al-26 nuclides in quartz bedrock samples collected during summers 1998-2003 indicate that landscape surfaces with a relict morphology (rounded symmetric morphology, tors, and fluvial valleys) predate the inundation of the last Fennoscandian Ice Sheet (typically 40-70 ka of exposure prior to the Holocene), and that erratic boulders on top of relict morphology and glacially scoured surfaces juxtaposed to relict morphology are of deglaciation age (typically 9-11 ka). Forthcoming measurements will further clarify the glacial history of the mountain range and rates of landscape change for glacial and relict surfaces, and guide the landscape history emerging from aerial photograph and GIS mountain geomorphology interpretation.
Funded by the Swedish Research Council and the U.S. National Science Foundation.

Tor, lowlands of northern Sweden

Palimpsest landscape of northeastern Sweden: Cosmogenic nuclide evidence for subglacial preservation of tors in Fennoscandian Ice Sheet core areas.

Collaborators:
Dr. Arjen Stroeven, Stockholm University, Sweden
Dr. Clas Hättestrand, Stockholm University, Sweden
Professor Jon Harbor, Purdue University, U.S.A. and PRIME Lab, Purdue University, U.S.A.

The principal objective is to obtain a measure of the total exposure time of tors on summit surfaces in a glaciated landscape. We have established the duration of cosmic ray bombardment some tors have experienced (~600 ka) and have constrained the maximum amount of erosion of these surfaces since exposure to cosmogenic rays (~1.6 m/Ma). This data shows that, at the very least, late Pleistocene glacial erosion over these tors was minimal. The implication is that frozen-based ice sheets prevailed over this area during this time and possibly during the whole Quaternary as suggested by Hättestrand and Stroeven (2001) on the basis of geomorphology alone.

Deciphering the glacial history of Northern Victoria Land, Antarctica using nunataks as indicators of ice sheet dynamics and landscape history.

Collaborators:
Dr. Paul Augustinus, University of Auckland, New Zealand
Dr. David Fink, Australian Nuclear Science and Technology Organisation

Controversial and conflicting interpretations have been proposed regarding the history of the East Antarctic ice sheet (EAIS) based on data from different sectors of the Transantarctic Mountains (TAM). Previous work in the North Victoria Land (NVL) sector suggests that the glacial history varies regionally as a consequence of complex tectonic controls so that identification of climatic influence on glaciation is problematic. Nevertheless, understanding of these complex controls is essential due to the ongoing and crucial debate regarding the long-term stability of the ice sheet and sensitivity of the ice sheets to climate change. The proposal involves detailed assessment of the history of the EAIS local ice dome and glaciers in NVL which contain records of global climate driven outlet glacier fluctuations that would be difficult to obtain from the Southern Victoria Land sector due to the influence of the Ross Ice Shelf (RIS) on the phasing of glacier expansion. We are working towards establishing: (1) the extent and dynamics of Late Cenozoic Antarctic ice sheet fluctuations in NVL using cosmogenic exposure dating; and (2) a framework by which improved understanding of the behaviour of the East Antarctic ice sheet and mechanisms of landscape evolution can be developed.

Burial dating of sediments in caves and alluvial sediments on bedrock terraces using the relative decay of Al-26 and Be-10.

Collaborators:
Prof. Brian Finlayson, University of Melbourne, Australia
Dr. John Webb, La Trobe University, Australia
Dr. Mike Sandiford, University of Melbourne, Australia
Dr. David Fink, Australian Nuclear Science and Technology Organisation

Understanding the response of rivers to climate change, sea-level fluctuation and tectonic uplift is important for reconstructing continental tectonic evolution, understanding the role of sea-level change in basin sedimentation, and reconstructing past climate change from the geomorphic record. A knowledge of the long-term evolution of bedrock river systems depends upon dating of the terraces and caves that flank many rivers. The terraces and horizontal cave passages represent periods of stillstand in the river history; river incision into a terrace/cave passage is triggered by either climate change and associated eustatic changes in base level, or by tectonic uplift, or both. Dating of the terraces/cave levels can help decide between these alternatives, but most previous dating techniques have been limited to the past few hundred thousand years. These dating time-scales are short relative to river incision on tectonically passive margins, and short relative to major climate changes such as the onset of aridity in southeast Australia. As a result, the evolution of bedrock river systems during Plio-Pleistocene tectonism and climate change remains poorly understood. To determine the driving mechanisms for bedrock river incision we require better age constraints for terrace/cave level formation and abandonment. Techniques using in situ produced cosmogenic nuclides have been developed to date sediments deposited over the past several million years Granger et al. (2001), and we propose to use these techniques to constrain the Plio-Pleistocene river incision history of several rivers in eastern Australia, in order to determine if the evolution of the river has been modulated by tectonism and/or climate change.