Long-term landscape evolution of the Northparkes region of the Lachlan Fold Belt, Australia: Constraints from fission track and paleomagnetic data

Apatite fission track thermochronology (AFTT) and paleomagnetic (PM) result s have been used to constrain the Late Paleozoic to Cenozoic landscape evol ution of the Lachlan Fold Belt (LFB) around the Northparkes copper-gold dep osit in east-central New South Wales. The present-day landscape of this reg ion of the LFB is relatively flat with little expression of the underlying rock and has previously been interpreted to indicate long-term stability of the region since the end of LFB orogenesis in the Early Carboniferous. Thi s was presumably borne out by PM analyses from thick weathered horizons wit hin open pits at the mine, which suggested that significant periods of weat hering, and hence relative landscape stability, prevailed during the Early to middle Carboniferous and at some time during the Cenozoic. Results from AFTT analyses, however, indicate that the region must have experienced sign ificant episodes of cooling/denudation during the mid-Permian to mid-Triass ic and during the early Cenozoic, as well as episodes of heating/burial dur ing the Late Carboniferous to mid-Permian and during the late Mesozoic. Whe n combined, the AFTT and PM results are in fact consistent and indicate tha t since the late Paleozoic the landscape of the LFB around the Northparkes deposit has evolved through multiple episodes of denudation and deposition as well as periods of relative stability during which the thick weathering horizons formed. Together these results establish a complementary chronolog ical framework that constrains the Late Palaeozoic to Cenozoic landscape ev olution of the Northparkes region and highlights the importance of using du al data sets in elucidating the long-term landscape evolution of Similar "s table" terranes.