Geology MERGED is an interpreted bedrock geology map of Western Australia that was created by combining limited 1:100 000 (100k) scale and statewide 1:500 000 (500k) scale geology data. The aim of the Geology MERGED layer was to create a single statewide interpreted bedrock geology map that incorporates geological data at the best available resolution.

Geology MERGED is created by combining the 1:100 000 and 1:500 000 State interpreted bedrock geology layers. These layers are based on published 1:100 000 and 1:250 000 Geological Series maps of Western Australia, together with Geological Survey of Western Australia’s (GSWA) published Geological Information Series (GIS), Geological Exploration Packages (GEP) and GA (Geoscience Australia formerly AGSO, BMR) regional geological maps. Information from these maps has been modified locally using geophysical datasets (magnetics, radiometrics and gravity), remote sensing imagery (ASTER and LANDSAT), seismic and magnetotelluric profiles, drilling, and unpublished geological mapping. The source package of each feature is captured as an additional attribute field. For adjacent but separately compiled packages, seamless interpretation along the edges of project areas has not been executed in order to preserve the spatial integrity of the source information. The nomenclature and hierarchy for the lithostratigraphic units in the polygon are based on the GSWA Explanatory Notes System (ENS).

The 1:500 000-scale layer is cut by the polygons of the 1:100 000-scale layer. The cut 500k-scale map is then merged with the 100k map. The final layer is coloured using the 500k and 100k symbology from the original layers. An additional field, SOURCE, records the source data as either 500k or 100k.