SA/NT Technical night: Alison Kirkby

Alison Kirkby: Integration of seismic, magnetotelluric and magnetic data to reveal crustal structure in the Arunta region, Central Australia

This presentation will show results from recent 3D inversions of magnetotelluric data along the 09GA-GA1 deep magnetotelluric and seismic reflection transect. The data were acquired from 39 broadband and 18 long period stations. The broadband data have been reprocessed, yielding an extended bandwidth of 0.004 to 1300 s. A 3D isotropic resistivity model provides a good fit to the data; however the presence of off-profile features with a similar spacing to the stations may suggest the presence of anisotropy in the Irindina Province. The resistivity model indicates at lying structure in the Davenport Province and overlying Georgina Basin, which contrasts with a tendency toward sub-vertical structure in the Aileron Province in the southern half of the line. Conductivity anomalies in the Aileron Province coincide with peaks in magnetic susceptibility as defined by inversions of Total Magnetic Intensity data, and are therefore interpreted in terms of a magnetic alteration mineral such as magnetite or an iron sulphide.

Biography

Alison joined Geoscience Australia in 2008 after completing her MSc in Geology at the University of Auckland. She worked in the Geothermal Section at GA until 2013. In 2013, she commenced a PhD at the University of Adelaide with Graham Heinson, looking at the resistivity characteristics of fractured rocks. After completing her PhD in 2016, she joined the MT and Seismic section at GA. Her current work involves developing the MTPy software package for MT data analysis, and the modelling and interpretation of new MT datasets.