|Latitude & Longitude (WGS84):||28° 8' 18'' South , 116° 42' 27'' East|
|Latitude & Longitude (decimal):||-28.13851,116.70756|
|Köppen climate type:||BWh : Hot deserts climate|
Numerous pegmatites surround the edge of a geographic feature called The Basin, named by E.S. Simpson, who was first to describe them. The pegmatites are 10-25 kilometres north of Yalgoo. The Basin GPS co-ordinates are suggested as 474,454E 6,885,912N UTM50 AGD66. Many of the pegmatites remain un-named and not described.
Harrison's Reward pegmatite contains two pits measured as 472,753E 6,887,359N and 472,789E 6,887,310N UTM50 AGD66. Simpson visited in 1913 and noted two shafts, the miners recovering bismutite, scheelite, quartz, and minor feldspar. Topaz was discovered at the site and nearby pegmatites in 1932. It is always associated with pseudomorphs of muscovite after topaz. The topaz is colourless, or milk white in masses up to 1.5kg in weight. These represent a single crystal with parts colourless and transparent to 5mm, and translucent to 10mm. They have been described as a F-type containing fluorine. (18.55%).
The pegmatite trends south-east and dips 70 degrees west, is highly siliceous composed mostly of quartz and biotite.
18 valid minerals.
Rock Types Recorded
Select Rock List TypeAlphabetical List Tree Diagram
Entries shown in red are rocks recorded for this region.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
2500 - 4000 Ma
|hi-Ca granite 74296|
Age: Archean (2500 - 4000 Ma)
Comments: igneous felsic intrusive; igneous intermediate intrusive; synthesis of multiple published descriptions
Lithology: Igneous felsic intrusive; igneous intermediate intrusive
Reference: Raymond, O.L., Liu, S., Gallagher, R., Zhang, W., Highet, L.M. Surface Geology of Australia 1:1 million scale dataset 2012 edition. Commonwealth of Australia (Geoscience Australia). 
|Neoarchean - Mesoarchean|
2500 - 3200 Ma
|Archean sedimentary and volcanic rocks|
Age: Archean (2500 - 3200 Ma)
Comments: Yilgarn Craton
Lithology: Mafic-ultramafic volcanic rocks
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529.