  We explore the origin of a ~280 m wide, heavily eroded circular depression in
Palm Valley, Northern Territory, Australia using gravity, morphological, and
mineralogical data collected from a field survey in September 2009. From the
analysis of the survey, we debate probable formation processes, namely erosion
and impact, as no evidence of volcanism is found in the region or reported in
the literature. We argue that the depression was not formed by erosion and
consider an impact origin, although we acknowledge that diagnostics required to
identify it as such (e.g. meteorite fragments, shatter cones, shocked quartz)
are lacking, leaving the formation process uncertain. We encourage further
discussion of the depression's origin and stress a need to develop recognition
criteria that can help identify small, ancient impact craters. We also
encourage systematic searches for impact craters in Central Australia as it is
probable that many more remain to be discovered.
