Late Neogene tectonics in northwestern Victoria: Evidence from the Late Miocene–Pliocene Loxton Sand

Abstract

The Late Miocene–Pliocene Loxton Sand strandplain extends across the western part of the Murray Basin in southeastern Australia. Gamma logging on groundwater bores surrounding Lake Tutchewop, which lies close to the eastern limit of this strandplain, showed that a heavy mineral layer within the Loxton Sand is displaced across the northern extension of the Leaghur Fault. A crevasse splay sand within the overlying Pliocene Shepparton Formation is also displaced, indicating that tectonic activity along the Leaghur Fault occurred in the Early Pliocene. This coincides with the Kosciusko Uplift, a major phase of Neogene tectonism across southeastern Australia, which also resulted in movement along the Danyo, Hindmarsh, Tyrell and Avoca Faults in northwestern Victoria.

Key words:

• Murray Basin
• Loxton Sand
• Neogene tectonics
• Lake Tutchewop
• Leaghur Fault
• Kosciusko Uplift
• southeastern Australia

Acknowledgements

We thank Paul Saunders of Goulburn-Murray Water for providing access to the groundwater bores and previously collected data, Aquaterra Pty Ltd for providing data collected from their field investigations at Lake Tutchewop, and Paul Starling and Jon Read of Borehole-Wireline Pty Ltd for the gamma logging services. Comments by Malcolm Wallace, Fons VandenBerg and an anonymous referee substantially improved this paper.