Tectonics units 1:500 000 (DMIRS-037)

The 2022 update of the digital '1:500 000 tectonic units of Western Australia' has been compiled using boundaries derived from the digital '1:500 000 State interpreted bedrock geology of Western Australia, 2020'. For the offshore component, the map uses data and divisions from the Geoscience Australia ‘Australian Geological Provinces’ GIS dataset, with polygons adjusted to match seamlessly into the onshore tectonic elements. The nomenclature and hierarchy for the tectonic units are based on weekly updates from the Explanatory Notes System (ENS). In order to provide the most up-to-date geological information for the units in question, attribution from the original source is modified to remove superseded units, display correct tectonic relationships and include more recent geochronology. Significant changes to the tectonic framework of Western Australia in this version include: a) the obsolete Speewah Basin is now included in the Kimberley Basin; b) the obsolete Gunbarrel Basin is now part of the Canning Basin; c) the obsolete Northern and Southern Bonaparte Basins are combined into a single Bonaparte Basin, and the onshore extent of the Petrel Sub-basin has been modified to include the Weaber Group, and the offshore extent modified accordingly; d) the new Burringurrah Domain has been defined as part of the Gascoyne Province; e) the basaltic component of the Carson Volcanics is now represented as part of the Hart – Carson Large Igneous Province, rather than the Kimberley Basin into which it was extruded; f) significant re-interpretation of the granite–greenstone domains in the southwestern part of the Yilgarn Craton; g) the boundary between the Northern Perth Basin and Southern Carnarvon Basin has been modified along the western margin of the Northampton Inlier, and the offshore boundaries adjusted accordingly; h) the obsolete Pardoo Shelf has been assigned to the Lambert Shelf and extended onshore to the east of Port Hedland. The State is the highest level unit in the hierarchy and is subdivided at the next level into Archean to Paleoproterozoic cratons; Proterozoic orogens; Archean, Proterozoic and Phanerozoic basins (or superbasins); and igneous supersuites. All units depicted on this map, with the exception of basins and some igneous supersuites, are at the third or lesser hierarchical level. Cratons are subdivided into superterranes, terranes and domains. Orogens are divided into provinces and orogenic forelands, and may also incorporate sedimentary basins; provinces are further subdivided into terranes/zones.