Uncovering new exploration frontiers through multi-scale data integration – an example from the East Tennant region, northern Australia

Abstract:

It is increasingly recognised that, in order to maintain a sustainable mineral resource development pipeline, the potential of covered regions needs to be unlocked. Effective mineral exploration in these regions presents a significant challenge and conventional approaches are no longer adequate. In order to facilitate the next generation of major discoveries it is necessary to recognise fertile mineral exploration fairways, understand key metallogenic processes and their geological expressions, and develop workflows to bridge scales and reduce the exploration search space.

The mineral systems concept provides a framework with which to predictively assess mineral prospectivity. We have applied this approach to a 550,000 km² area between Tennant Creek and Mount Isa in northern Australia. Although this region hosts a number of known deposits in exposed Paleoproterozoic basement rocks, vast areas have no known mineralisation and have experienced very little exploration to date owing to the presence of younger cover sequences.

A new prospective mineral exploration fairway of 25,000 km², the East Tennant region, has been identified though mapping large-scale controls on mineral system formation deep in the Earth’s mantle and crust, together with smaller-scale, upper crustal evidence of mineralising processes. Key indicators of the region’s potential include lithospheric-scale architecture, elevated electrical conductivity in the crust and mantle, and modelled and demonstrated hydrothermal alteration in the near surface. These provide evidence of pathways for large-scale fluid and metal transfer, fertile source regions, and ore depositional sites and gradients. A targeted broadband magnetotelluric survey, acquired to bridge scales and depths, shows evidence for crustal-scale fluid flow along mapped major structures and connects conductivity features in the mantle with upper crustal expressions of mineral systems accessible to exploration.

These interpretations allow development of testable mineral system predictions which should have an expression in the geological record. These will be further investigated through a planned stratigraphic drilling program. This multi-scale, multi-disciplinary approach to mineral exploration can be utilised in other greenfield regions undercover.