Principal Investigators:
Dr. Melba Crawford, University of Texas
Dr. Vic Baker, University of Arizona

The east-west trending fold belt of central Australia is developed in a thick sequence of Late Proterozoic through Carboniferous rocks [Wells et al., 1970]. Resistant sandstone units form long strike ridges with superimposed river gorges. The ridges are locally flanked by the dissected remnants of debris-mantled pediment surfaces of middle to late Tertiary age [Baker, 1988, fig. 4A]. These surfaces comprise remnants of a deeply weathered Tertiary landscape that formerly existed in the valleys between the resistant ridges [Mabbutt, 1966].

1993 TOPSAR mosaic of Central Australia

The Mesozoic and Tertiary history of this region was marked by prolonged denudation and the formation of multiple planation surfaces [Baker, 1986b]. The nature of the weathering and planation changed during this period from deep tropical weathering in the late Mesozoic and early Tertiary to arid conditions in the late Tertiary and Quaternary. During the middle and late Tertiary an episode of extensive silicification resulted in the formation of extensive siliceous duricrusts. These locally mantle remnants of the middle/late Tertiary landscape are preserved in strike valleys between the sandstone ridges [Twidale and Milnes, 1983)].

Near Palm Valley, the Finke River has cut a spectacular gorge across the trend of the ranges. The crests of the sandstone ridges are beveled by a regional planation surface [Baker and Twidale,1991, fig. 6]. This surface appears to be regionally deformed [Baker, 1993], but quantitative analysis of topography is needed to establish this hypothesis and its consequences. Pickup et al. [1988] describe the history of planation and the nature of paleoflood features in the Finke Gorge.

As an ancient inland mountain river system, the Finke River area provides excellent opportunities for quantitative paleoflood hydrology both in Australia and other arid environments where extreme events define the morphology of the riverine system [Baker et al., 1983, 1987, 1988].

Data for Proposed Study
An extensive set of remotely sensed imagery has been acquired and is available for the project. The Australian receiving station acquires every pass of Landsat and SPOT data, most of which is cloud free over this area. A 1972 Landsat MSS image, a 1994 Landsat TM image, two multispectral SPOT images (12/95 and 12/96), and color infrared photography of the Gorge acquired by the Australian government for mapping in the 1970's are available for the study. Several space-based radar scenes from ERS which are suitable for interferometry and radar stereo have already been acquired for the project [Figure ****] The shuttle also acquired SIR-C and X-SAR data over the site in both April and October of 1994. Both AIRSAR and TOPSAR flight lines were obtained by JPL in 1993 over Palm Valley and in 1996 over the Finke River Gorge [Figure **]. A RADARSAT scan mode scene and a JERS scene have been requested over the area.

In addition to remotely sensed data, extensive field data have been collected for the Finke River National Park and bordering areas. A vegetation and soils survey of the West MacDonnell Ranges was completed in the past 5 years and is available in a vector GIS through the Northern Territory Conservation Commission, which will collaborate on the study. GPS survey data, including elevations, acquired by the Magellan Petroleum Company will also be made available for the study. Dr. Crawford will spend June 1997 at CSIRO in Alice Springs and in the Finke River National Park area collecting field data for the geomorphological interpretations.

Analysis to be conducted during the proposed study