Tectonics of the Alice Springs Orogen: Evaluating the significance of deformation in the Entia Gneiss Complex, Harts Ranges, central Australia

Project Investigator

Stacey Curtis (Hons. 2005)

Project Details

The aim of this project was to constrain the timing and style of exhumation of the Entia Gneiss Complex in the Harts Ranges, central Australia, using metamorphic and geochronological tools, in order to evaluate the evolution of apparent extensional structures within the context of compressional phases of the Alice Springs Orogeny.

There is growing evidence that the Alice Springs Orogeny was a complex system involving several distinct phases of compressional deformation. In addition, there are a number of enigmatic domains within the eastern Alice Springs Orogen that appear to support the notion that phases of compressional deformation were separated by orogenic extension. The Entia Gneiss Complex in the Harts Ranges is defined by a Palaeozoic regional scale sub-horizontal shear fabric which formed during near-isothermal lower crustal decompression. Pegmatite dyke swarms were emplaced in the Harts Ranges during NE-SW extension during the Palaeozoic Era. However, there has been little focus on the evolution of the Entia Gneiss Complex, and no evaluation of whether it represents major extensional collapse of the Alice Springs Orogen, which was the focus of this project.