Australia: The Land Where Time Began

A biography of the Australian continent 

Australian Bedrock Erosion - Exceptionally Low Rates and the likelihood of pre-Pleistocene Landscapes based on ¹⁰Be and ²⁶Al evidence

Some of the Australian inselbergs (granite domes) are among some  of the most stable geomorphic surfaces in the world, as shown by analysis of ¹⁰Be and ²⁶Al, eroding at rates of 0.6 m/million years. It is suggested by 20 isotopic analyses of 10 samples taken from the top of these isolated granite domes that the bare bedrock on top of these domes, that they has been exposed to cosmic radiation for at least 0.5 My, eroding at a mean model rate of 0.7 ± 0.1 m/My (n=6). Samples from the top of Mt. Wudinna, Little Wudinna and Yarwondutta Rock are the most consistent, isotopic analyses indicating that exposure has been continuous during erosion, while samples from the flanks of some domes and the tops of other domes, have isotopic abundances that are suggestive of exposure histories that are complex, that include burial and reexposure. The first quantitative information for evaluating long-standing, though untested hypotheses regarding the development and antiquity of these enigmatic landforms is provided by these unique isotopic data, which indicates that some inselbergs on the Eyre Peninsula are probably relict features from pre-Pleistocene landscapes.

Sources & Further reading

1. Bierman, Paul, and Jill Turner. "10be and 26al Evidence for Exceptionally Low Rates of Australian Bedrock Erosion and the Likely Existence of Pre-Pleistocene Landscapes." Quaternary Research 44, no. 3 (11// 1995): 378-82.