Abstract
The McKinnons gold mine, ∼35 km southwest of Cobar in New South Wales is a non-operational opencut mine with extensive regolith profile development down to a depth of ∼80 m. Twenty-three oriented paleomagnetic samples, from saprolite at different levels through the profile, yielded two well-defined paleomagnetic poles, one of Paleocene age (60 ± 10 Ma), and the other of Miocene age (15 ± 4 Ma). These reflect two periods of remagnetisation associated with deep, intense, oxidative weathering under humid conditions. They provide important time constraints for the history of climate change, weathering and landscape evolution of the Cobar region.
Acknowledgements
This study was supported by the Australian Government's Cooperative Research Centre program within CRC LEME and also by the Australian National University. We thank Troy Resources for allowing access to the McKinnons mine site, and Colin Pain and Keith Scott for helpful reviews. MLS would like to thank Dave Cohen at the University of New South Wales for supervision during part of the project. Comments by two anonymous reviewers are also gratefully acknowledged.