Depth to the Mohorovičić discontinuity (Moho) interpreted and modelled by Geognostics with support from government and industry. The Moho surface is the boundary between the Earth's crust and the upper mantle. The depth to moho is a representation of the thickness of the Earth's Crust. This moho surface is derived from seismic, gravity and other geophysical datasets.

Please view Matthews and Sheldon (2024) for full description and instructions: Contact Sam at samuel.matthews@regional.nsw.gov.au if you have any difficulty accessing the paper.

Geothermal gradient model (2023) created by Geognostics with support from government and industry. The geothermal gradient describes how temperature increases with depth inside the Earth. It is expressed in degrees Celsius per kilometre (°C/km). The linear geothermal gradients are from the top of SEEBASE to the surface. These were calculated using the combined heat-flow contribution of multiple crustal heat sources including upper mantle, radiogenic upper crust, and sediment thickness. The highest calculated geothermal gradients are generally related to areas interpreted to be underlain by granitic intrusions in the basement. The composition and heat production characteristics of the granites are largely unconstrained by analyses

This data set is modified from the Australian Geological Provinces Database (Geoscience Australia) and contains descriptions and spatial extents of the fundamental geological elements of NSW. Province types include sedimentary basins, tectonic provinces such as cratons and orogens, igneous provinces, and metallogenic or mineral provinces. At its simplest, a province may describe a sedimentary basin and its fill (e.g. the Sydney Basin). However, provinces may also be defined by a complex history of tectonics, metamorphism, magmatism, or metallogenesis. Provinces outlines, including their subsurface extent, are compiled at around 1:1 million scale. Descriptions of the provinces include age and geological history, parent-child hierarchy, constituent stratigraphic units and relations to surrounding provinces.

Geophysics survey data has been reported to the NSW government and released under the requirements of the NSW Mining Act 1992. Contained within this vector file is the location of surveys and acquisition parameters. These surveys use uncommon techniques.

Depth to the Lithosphere–Asthenosphere Boundary (LAB) modelled by Geognostics with support from government, academia and industry. The LAB surface is the base of the ridgid lithosphere and the top of the ductile asthenosphere. In geothermal terms it marks a thermal and mechanical tranisition in the Earth at a temperature of 1330 °C. This surface is modelled using themal modelling (mantle heat flow, crustal heat production, thermal conductivity, Moho depth and lithospheric structure) seismic tomography, magnetotellurics, global and regional geodynamic models and tectonic context.

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.

Depth contours derived from the NSW Basement Elevation Model.

Pseudocolour image of isostatic residual gravity with a histogram-equalised colour-stretch. Cooler colours indicate lower gravity values and warmer colours represent higher values. The image has been enhanced with a 3×3 sun filter with the sun illumination set at 45 degrees elevation and 90 degrees azimuth. Bouguer gravity compensates for variations in latitude, 'free-air' elevation and Bouguer correction (assuming a crustal density of 2.67 T/m³). The isostatic correction removes the effect of the thickness of Earth’s crust due to changes in topography. Attention: Please ensure your version of the NSW gravity merges contains the date ‘2024-10-30’ in their filename. An update was made to remedy location errors in the initial release. Apologies for any inconvenience.