Comparison of the Proterozoic Apparent Polar Wander Path (APWP) for
Australia with the corresponding geology of northern Australia suggests
that a number of discrete interplate tectonic events, manifested on the
APWP as bends or inflections, may have controlled sedimentary basin
evolution, ore fluid production and the timing of mineralisation. Similar
features in the Phanerozoic APWP for the North American plate appear to
correlate with major orogenic events, basin deformation, movement and
'entrapment' of hydrocarbons and minerals. Interplate tectonic events
cause intraplate deformation which in turn controls the subsidence/uplift
and sedimentation histories of the basins. Interplate events are thus
responsible for creating, deforming and destroying sedimentary basins
and the associated petroleum and mineral systems. The basins of northern Australia show remarkable similarities in the
successions of volcanic and sedimentary deposits. Unconforrnities of
regional or sometimes only local extent have been mapped between the
major sedimentary sequences and it is predicted that interplate tectonic
events corresponding to bends or inflections on the APWP directly reflect
the processes that have produced these widespread unconformities. These
processes are also likely to have controlled the geometry and character of
the fluid migration pathways and hence the mineralising events.
Palaeomagnetic studies of Proterozoic rocks in sedimentary basins
provide a tool for predicting the timing of regional mineralisation events,
particularly for low-temperature mineral systems. The techniques, when
coupled with systematic regional basin analysis, using petroleum
exploration techniques, may identify a number of new mineral 'plays' in
northern Australia. Prominent inflections in the APWP occur at approximately 1700, 1670,
1650, 1600, 1540, and 1480 Ma. Each of these may be related to a
regional compressional deformation, important mineralising event, or
significant change in style and type of sedimentation. Most appear to be
associated with magnetic overprints. Some of the inflections between
1400 and 540 Ma may also mark significant events in the evolution of
Meso- and Neoproterozoic basins. Further work is required to correlate
inflections in the APWP with alteration events in order to understand their
regional significance.