Geoscience Australia, in partnership with State and Territory Geological Surveys and research organisations,
has applied the magnetotelluric (MT) method to image the resistivity structure of the Australian continent over
the last decade. Data have been acquired at nearly 5000 stations through the collaborative national AusLAMP
survey and regional MT surveys. The data provide valuable information for multi-disciplinary interpretations
that incorporate various datasets. Most of these MT data have been released to the public.
To date, AusLAMP has been completed ~30% of the national coverage. Data have been acquired at nearly
1000 stations. This pre-competitive dataset will be an essential input to Geoscience Australia’s Exploring for
the Future program as well as a valuable resource for researchers to reconstruct the tectonic evolution of the
Australian continent.
The regional MT surveys have been undertaken across potential mineral/energy provinces and greenfields
areas in the Australia continent. A number of regional surveys have been completed recently. The MT data
from the poorly understood Southern Thomson Orogen and Coompana region have improved understanding
of cover thickness, sub-surface geology, and crustal architecture. The data reduce the uncertainty associated
with intersecting the targeted stratigraphy for the pre-competitive stratigraphic drilling program. Comparison
with drill-hole information indicates that the technique is capable of identifying major stratigraphic structures
and providing cover thickness estimates with reasonable accuracy in regions where there is little surface
outcrop and thick cover sequences.
The MT data from the Mount Isa inlier in northern Australia provide new insights into basement architecture,
the crustal architecture and resource potential in this region. The data reveal some crustal-scale conductivity
anomalies which correspond to known major crustal boundaries and faults. Those faults and boundaries are
considered the primary factors in the partitioning of mineralisation in the region, with some conductors in the
upper crust coinciding with known mineral deposits.
Presented at the 24th Electromagnetic Induction Workshop (EMIW) 13-20 August 2018, Helsingør Denmark
(https://emiw2018.emiw.org/)
