The depth to magnetic bottom (Curie point depth) is the deepest possible horizon in the crust up to which crustal magnetisation contribution remains significant to the measured magnetic field on the horizontal surface of the Earth. The primary cause of rock magnetisation is due to distribution of ferrimagnetic minerals within. The magnetisation property of such minerals depends on the temperature. At a critical temperature, known as Curie temperature the ferrimagnetic minerals become paramagnetic and contribute insignificantly in the measured magnetic field. Magnetite is a ferrimagnetic mineral which is most abundantly exists in the earth's crust. Curie temperature of magnetite is ~ 580o C. Since temperature increases with depth in general the depth to the magnetic bottom may be considered in a suitable geological condition as a proxy for Curie temperature. The name Curie point depth is then synonymous to the depth to the magnetic bottom

No abstract available

The map addresses the distribution of Archaean rocks of the central Eastern Goldfields of Western Australia. Interpretation was undertaken at 1:250 000 scale for both Geoscience Australia aeromagnetic data (400m linespacing) and Fugro Airborne Surveys Pty. Ltd. data (200m linespacing). The Archaean rocks are subdivided into undivided gneiss-migmatite-granite (Agmg), banded gneiss (Agn), 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. The map is derived from a subset of a more extensive interpretation covering the exposed extent of the Yilgarn Craton.

No abstract available

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.

No abstract available

This data set was compiled to provide geological context for the 2001 seismic reflection line acquired between Leonora and the northwest of the Neale 1:250 000 sheet. The data set includes reviewed solid geology for the Leonora (Blewett) and Laverton (Whitaker) 1:250 000 sheets but also includes 1:100 000 sheets for northeast Menzies and northern Edjudina 1:250 000 sheet areas as well as aeromagnetic interpretation of the Rason and Neale 1:250 000 sheets. Archaean rocks of the Eastern Goldfields Province of the Yilgarn Craton form basement to the area traversed in the seismic survey. In the west, granite and abundant greenstone of the Norseman-Wiluna Belt are dislocated by major north-northwest to north oriented shear zones. East of the Norseman-Wiluna Belt, the crust is dominated by granitic lithologies with shear zones and greenstone in much lower abundance. Gneiss of the Proterozoic Albany-Fraser Province abuts the Yilgarn Craton about 50 km to the east of the eastern end of the seismic line.

The map addresses the distribution of Archaean rocks of the Yilgarn Craton but includes interpretation of overlying Proterozoic rocks (Yerida, and Earaheedy groups). Interpretation was undertaken at 1:250 000 scale for AGSO aeromagnetic data (400m and 1500m linespacing data) and for Fugro Airborne Surveys Pty.Ltd. coverage of the Menzies Sheet (200m linespacing data), and 1:500 000 scale for Fugro Airborne Surveys Pty.Ltd. coverage of the Kalgoorlie, Kurnalpi and Widgiemooltha Sheets (200m linespacing data). The Archaean rocks are subdivided into undivided gneiss-migmatite-granite (Agmg), banded gneiss (Agn), 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. The map is derrived from a subset of a more extensive interpretation covering the exposed extent of the Yilgarn Craton.