Abstract
Intraplate thrusting, involving reactivation of a mid-Proterozoic province boundary within the basement metamorphic rocks of the Arunta block, occurs at the northern margin of the late Proterozoic to mid-Palaeozoic Amadeus Basin in central Australia. Earlier geological and geophysical studies show that the thrust system, referred to as the Alice Springs orogen, is 'thick-skinned' in the central part of the thrust belt and was dominated by the crust-cutting Redbank thrust zone. Several episodes of thrusting, defined stratigraphically, began about 400 Ma ago. Analysis and modelling of 40 Ar- 39 Ar age spectra on K-feldspar from the basement rocks, combined with regional geological constraints, point to cooling rates of 3–10 °C/Ma and moderate overall exhumation rates of 100–400 m/Ma during the Alice Springs orogeny, without appreciably increased heat flow. However, final uplift along the thrust front at 300–320 Ma was rapid, as the time of final closure of small domains in K-feldspar approximates apatite fission track ages. By using 40 Ar- 39 Ar age data as a constraint, together with available geological and geophysical data, crustal shortening across the thrust belt is thought to be approximately 20 to 30%. Overall convergence rates of 0.6–3 km/Ma are slow compared with rates of ≥ 5 km/Ma for continent-continent collision zones.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.