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| Titel |
Fluid–rock interaction and thermochemical evolution of the eastern Alice Springs Orogen, central Australia |
| VerfasserIn |
Jan Varga, Martin Hand, Tom Raimondo, David Kelsey |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250154363
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| Publikation (Nr.) |
 EGU/EGU2017-19447.pdf |
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| Zusammenfassung |
| The Harts Range rift and basement complex is located in the eastern Alice Springs Orogen,
central Australia. For the period 450–320 Ma, this tectonic domain is characterised by
large-scale deformation of the Harts Range Group rift sequence and pervasive reworking of
its underlying basement. Fluid–rock interaction is evidenced by extensive pegmatite intrusion
and retrogression occurring episodically throughout this 130 Myr period, possibly coeval
with prograde upper-amphibolite facies metamorphism. The orthogneiss-dominated Entia
Gneiss Complex (EGC) represents basement structurally underlying the Harts Range Group,
and has evidence for associated deformation and fluid ingress between 390–320
Ma. The EGC also contains metapelites at various structural levels of the mid- to
lower-crust, providing a means to constrain the thermobarometric record during a
period of significant rheological weakening. Despite existing studies, the source of
fluid that contributed to pervasive deformation and metamorphism is unresolved.
Additionally, the role of fluid in the episodic history of crustal melting, and ultimately the
generation of large-scale tectonic reworking in the Harts Range Group, remains unclear.
In this contribution, we integrate U–Pb monazite geochronology, geochemistry,
petrography and phase equilibria forward modelling from various metapelitic rocks at
different structural levels of the Entia Gneiss Complex. Preliminary data show that
the timing of metamorphism coincides with pegmatite crystallisation ages. These
constraints form the basis for understanding the conditions and timing at which
fluid flow occurred, and the potential sources of the fluid will be constrained by
stable isotope analyses (δ18O and δD). The combination of in situ geochronological
data with petrographic observations linked to P − T models is vital in providing
temporal constraints on the physical and thermal evolution of the reworking event. |
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