The NSW Seamless Geology Project was originally a five-year initiative of the Geological Survey of New South Wales which commenced in late 2013 and aimed to provide a statewide compilation of the best available digital geological mapping data in an internally consistent format. The overarching aims of the NSW Seamless Geology Project were to: (i) compile the different original scales, formats and rock unit naming conventions into a consistent, statewide format; (ii) edge-match the geology across existing map sheets; and (iii) interpret the basement geology under cover. The resulting geodatabase comprises a series of layers which include: (i) solid basement geology; (ii) cover rocks (defined as undeformed and unmetamorphosed); (iii) Mesozoic igneous rocks; and (iv) Cenozoic sedimentary and igneous rocks. Due to the size of the project, the work was divided into UTM zones, starting in the east with Zone 56, then moving west to Zone 54, and finishing with Zone 55. The western half of Zone 55 was completed in 2018, after which the results were merged with the previously completed Zones to produce version 1 of the NSW Seamless Geology dataset. Completion of this stage saw the end of phase 1 of the Seamless Geology Project, but it is intended that the Seamless Geology dataset will be continually updated and refined as new digital geological mapping data becomes available. Updates to the Seamless Geology dataset generally occur on an annual basis. Version 2.4 is the 6th major update to the NSW Seamless Geology and was released in May 2024. This release includes: a major upgrade to the geological mapping of the Sydney Basin; significant upgrades to the mapping of numerous areas in the Permian-Mesozoic Igneous Province and the Lachlan Orogen (particularly the Cadia Valley, Lake Cowal and Quarry Creek areas); and attribute updates, data additions, and minor error fixes to all layers. NOTE: A substantial amount of overlay, erase and intersect geoprocessing of the original multi-layered Seamless Geology was undertaken to produce the single layer surface NSW Seamless Geology dataset. Due to small tolerance differences between different layers in the Seamless Geology dataset, this has, in some places, created small “sliver” polygons between boundaries common to more than one layer of the original multi-layered NSW Seamless Geology. This is a known issue with the current single layer Seamless Geology dataset and while some attempt has been made to resolve these issues, a number of small “sliver” polygons remain. Users are cautioned to be aware of this problem when using this dataset at high zoom levels (ie. under 1:1,000 scale) and to refer to the full Seamless Geology dataset for clarification.

In 2016, the Geological Survey of NSW (GSNSW) published a state-wide depth to basement 3D model (Robinson 2016, 2017). Since then, new geological and geophysical data have been released and used for the construction of basin-scale 3D geological models for the southern Thomson Orogen and the Sydney, Gunnedah and Bowen basins (Davidson 2019; Oliveira and Davidson 2019; Oliveira et al. 2019). The basement topography under these regions was refined and the results have now been incorporated into the updated state-wide depth to basement 3D model reported herein.

The NSW Seamless Geology Project was originally a five-year initiative of the Geological Survey of New South Wales which commenced in late 2013 and aimed to provide a statewide compilation of the best available digital geological mapping data in an internally consistent format. The overarching aims of the NSW Seamless Geology Project were to: (i) compile the different original scales, formats and rock unit naming conventions into a consistent, statewide format; (ii) edge-match the geology across existing map sheets; and (iii) interpret the basement geology under cover. The resulting geodatabase comprises a series of layers which include: (i) solid basement geology; (ii) cover rocks (defined as undeformed and unmetamorphosed); (iii) Mesozoic igneous rocks; and (iv) Cenozoic sedimentary and igneous rocks. Due to the size of the project, the work was divided into UTM zones, starting in the east with Zone 56, then moving west to Zone 54, and finishing with Zone 55. The western half of Zone 55 was completed in 2018, after which the results were merged with the previously completed Zones to produce version 1 of the NSW Seamless Geology dataset. Completion of this stage saw the end of phase 1 of the Seamless Geology Project, but it is intended that the Seamless Geology dataset will be continually updated and refined as new digital geological mapping data becomes available. Updates to the Seamless Geology dataset generally occur on an annual basis. Version 2.5 is the 7th major update to the NSW Seamless Geology and was released in May 2025. This release includes: a new layer to capture Cenozoic ‘sub-basaltic gravels and deep leads’; significant upgrades to the mapping of numerous areas in the Lachlan Orogen (particularly the Coolac Serpentinite Belt, Gilmore Fault Zone, and the Eden-Merimbula area); a major update to the mapping of the Gunderbooka 1:100,000 map sheet area and the Port Macquarie–Laurieton area; and attribute updates, data additions, and minor error fixes to all layers. NOTE: A substantial amount of overlay, erase and intersect geoprocessing of the original multi-layered Seamless Geology was undertaken to produce the single layer surface NSW Seamless Geology dataset. Due to small tolerance differences between different layers in the Seamless Geology dataset, this has, in some places, created small “sliver” polygons between boundaries common to more than one layer of the original multi-layered NSW Seamless Geology. This is a known issue with the current single layer Seamless Geology dataset and while some attempt has been made to resolve these issues, a number of small “sliver” polygons remain. Users are cautioned to be aware of this problem when using this dataset at high zoom levels (ie. under 1:1,000 scale) and to refer to the full Seamless Geology dataset for clarification.

Map blocks and map units are based on a system originally devised by the British Ordinance Survey. Each 1:1 million scale map sheet is subdivided into 3456 graticular map blocks, each measuring 5’ of latitude by 5’ of longitude. These map blocks are further subdivided into 25 1’ by 1’ map units. A map unit is approximately 3 square kilometres in size.

The Geological Survey of NSW developed a Seamless Geology of UTM Zone 56 during2014 as part of a project to develop a seamless vector geology dataset of the best available geological mapping data covering the whole of NSW.The overarching aims of the Statewide Seamless Geology Project were to: (i) compile the different original scales, formats and rock unit naming conventions into a consistent, statewide format; (ii) edge-match the geology across existing map sheets; and (iii) interpret the basement geology under cover. The resulting geodatabase comprises a series of layers which include: (i) solid basement geology; (ii) cover rocks (defined as undeformed and unmetamorphosed); (iii) Mesozoic igneous rocks; and (iv) Cenozoic sedimentary and igneous rocks. The project was divided into 3 major stages corresponding to the UTM zones which divide New South Wales. This dataset includes the seamless geology layers from the NSW portion of UTM Zone 56 (ie.east of 150 degrees longitude to the coast).

The Geological Survey of NSW developed a Seamless Geology of UTM Zone 56 during 2014 as part of a project to develop a seamless vector geology dataset of the best available geological mapping data covering the whole of NSW.The overarching aims of the Statewide Seamless Geology Project were to: (i) compile the different original scales, formats and rock unit naming conventions into a consistent, statewide format; (ii) edge-match the geology across existing map sheets; and (iii) interpret the basement geology under cover. The resulting geodatabase comprises a series of layers which include: (i) solid basement geology; (ii) cover rocks (defined as undeformed and unmetamorphosed); (iii) Mesozoic igneous rocks; and (iv) Cenozoic sedimentary and igneous rocks. The project was divided into 3 major stages corresponding to the UTM zones which divide New South Wales. This dataset includes the seamless geology layers from the NSW portion of UTM Zone 56 (ie.east of 150 degrees longitude to the coast).

The Geological Survey of NSW developed a Seamless Geology of UTM Zone 56 during 2014 as part of a project to develop a seamless vector geology dataset of the best available geological mapping data covering the whole of NSW.The overarching aims of the Statewide Seamless Geology Project were to: (i) compile the different original scales, formats and rock unit naming conventions into a consistent, statewide format; (ii) edge-match the geology across existing map sheets; and (iii) interpret the basement geology under cover. The resulting geodatabase comprises a series of layers which include: (i) solid basement geology; (ii) cover rocks (defined as undeformed and unmetamorphosed); (iii) Mesozoic igneous rocks; and (iv) Cenozoic sedimentary and igneous rocks. The project was divided into 3 major stages corresponding to the UTM zones which divide New South Wales. This dataset includes the seamless geology layers from the NSW portion of UTM Zone 56 (ie.east of 150 degrees longitude to the coast).

In 2016, the Geological Survey of NSW (GSNSW) published a state-wide depth to basement 3D model (Robinson 2016, 2017). Since then, new geological and geophysical data have been released and used for the construction of basin-scale 3D geological models for the southern Thomson Orogen and the Sydney, Gunnedah and Bowen basins (Davidson 2019; Oliveira and Davidson 2019; Oliveira et al. 2019). The basement topography under these regions was modelled using constraints from drillholes, seismic, Seamless Geology, magnetics and gravity data. The results have now been incorporated into the updated Statewide 3D Basement Elevation Model reported herein.

The Geological Survey of NSW developed a Seamless Geology of UTM Zone 56 during 2014 as part of a project to develop a seamless vector geology dataset of the best available geological mapping data covering the whole of NSW.The overarching aims of the Statewide Seamless Geology Project were to: (i) compile the different original scales, formats and rock unit naming conventions into a consistent, statewide format; (ii) edge-match the geology across existing map sheets; and (iii) interpret the basement geology under cover. The resulting geodatabase comprises a series of layers which include: (i) solid basement geology; (ii) cover rocks (defined as undeformed and unmetamorphosed); (iii) Mesozoic igneous rocks; and (iv) Cenozoic sedimentary and igneous rocks. The project was divided into 3 major stages corresponding to the UTM zones which divide New South Wales. This dataset includes the seamless geology layers from the NSW portion of UTM Zone 56 (ie.east of 150 degrees longitude to the coast).

The Geological Survey of NSW developed a Seamless Geology of UTM Zone 56 during 2014 as part of a project to develop a seamless vector geology dataset of the best available geological mapping data covering the whole of NSW.The overarching aims of the Statewide Seamless Geology Project were to: (i) compile the different original scales, formats and rock unit naming conventions into a consistent, statewide format; (ii) edge-match the geology across existing map sheets; and (iii) interpret the basement geology under cover. The resulting geodatabase comprises a series of layers which include: (i) solid basement geology; (ii) cover rocks (defined as undeformed and unmetamorphosed); (iii) Mesozoic igneous rocks; and (iv) Cenozoic sedimentary and igneous rocks. The project was divided into 3 major stages corresponding to the UTM zones which divide New South Wales. This dataset includes the seamless geology layers from the NSW portion of UTM Zone 56 (ie.east of 150 degrees longitude to the coast).