Yilgarn Craton 1:1 million aeromagnetic interpretation dataset

Brief description

This product covers interpretation of the full geophysical extent of the Yilgarn Craton, and also most of the Albany-Fraser province to the south-southeast. The interpretation covers the Meekatharra (SG50), Wiluna (SG51), Perth (SH50), Kalgoorlie (SH51), Albany (SHI50), and Esperance (SI51) 1:1M sheets. The data set predominantly addresses the Archaean rocks of the Yilgarn Craton but includes interpretation of the adjacent, abutting or onlapping Proterozoic rocks such as the Northampton Block, Yerida, Bryah, Padbury and Earaheedy groups, Albany-Fraser Province, Stirling and Mt Barren Beds, and Phanerozoic Perth and Officer Basins. The aeromagnetic interpretation provides most information on the distribution of the Archaean rocks as these rocks are generally moderately to highly magnetised with reasonable variation of magnetisation. Adjacent Perth Basin sediments are poorly magnetised and spatially associated magnetic anomalies are attributed to underlying Proterozoic rocks. The Archaean rocks are subdivided into undivided gneiss-migmatite-granite (Agmg), banded gneiss (Agn), sinuous gneiss (Anu), greenstone (Aa), and granite plutons (Ag). Where important relative differences in magnetisation are mapped, the geophysical map units include the suffixes _h (high), _m (medium), _l (low) and _r (remanent) for the level of magnetisation. Dykes, faults, and unassigned small intrusives are also mapped. Large Archaean domains equivalent to geologically defined Provinces are also defined including Narryer, Murchison, Toodyay- Lake Grace, Southwest, Southern Cross, Yeelirrie, Lake Johnston and Eastern Goldfields domains.

Lineage

Maintenance and Update Frequency: irregular

Statement: The lines and polygons of the aeromagnetic interpretation were drawn on film overlaying images and contour plots at 1:250 000 scale. Images and contour plots of TMI were used for 3000m and 1500 m line spaced data (most of the map sheets) while images only of TMI and 1st vertical derivative of TMI were used for 400 m / 200 m data (~20 sheets). The film drawings were subsequently scanned, digitised on screen and attributed.