2.3

COLQUHOUN G.P., HUGHES K.S., DEYSSING L., BALLARD J.C., FOLKES C.B, PHILLIPS G., TROEDSON A.L. & FITZHERBERT J.A. 2023. New South Wales Seamless Geology dataset, version 2.3 [Digital Dataset]. Geological Survey of New South Wales, Department of Regional NSW, Maitland.

This data is part of the New South Wales Seamless Geology database, version 2.3, which is a statewide compilation of the best available digital geological mapping data in an internally consistent GIS format.

Dataset Authors:

Colquhoun, G.P.

Hughes, K.S.

Deyssing, L.

Ballard, J.C.

Phillips G.

Troedson, A.L.

Folkes C.B.

Fitzherbert J.A.

Scheduled updates to this dataset are planned as new data becomes available.

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Version 6.2 (Build 9200) ; Esri ArcGIS 10.4.0.5524

The dataset covers the land areas of New South Wales, Australia (including Lord Howe Island). A 10 km buffer into Queensland and Victoria is also included.

The NSW Seamless Geology Project team has compiled the best available geological data for the state into an internally consistent geodatabase. As part of the compilation process, contributing datasets were organised into a series of layers, or time slices, that represent the major lithotectonic subdivisions of the state’s geology. The data was then stitched/smoothed along existing map and dataset boundaries to create a seamless dynamic model of the geology of NSW. Important datasets and projects that contributed to the NSW Statewide Seamless Geology dataset are detailed below.

The Seamless Geology Project commenced in 2013 when merges of the best available datasets began to be assembled in the Statewide Geology Geodatabase (v.2) format. The source datasets for these merges are shown in the feature class “Seamless_V1_Source_Datasets” in this geodatabase. This merged dataset was divided into stratotectonic layers which were then edited by a small team of geologists, resolving edge-match issues and nomenclature problems between the geology of adjacent map sheets, and interpreting various layers under the cover of overlying layers. This produced a series of seamless geology layers which showed, for the first time, the actual distribution of rock units and structures, both in outcrop and under cover. These datasets were released progressively across the state as this work was completed, with three packages having been previously released; a Zone 56 dataset (Colquhoun, Phillips, Hughes, Deyssing, Fitzherbert & Troedson 2015), a Zone 54 dataset (Colquhoun, Phillips, Ballard, Hughes & Deyssing 2016) and a Zone 55 East dataset (Colquhoun, Deyssing, Ballard, Hughes & Troedson 2017). Zone 55 West was completed in mid-2018 but was not released as a separate dataset. Instead, the Zone 55 West data was merged with the previously released Seamless Geology datasets from the various zones and merged and harmonised to produce the first statewide Seamless Geology of NSW (version 1) in October 2018.

Updates to the Seamless Geology dataset have occurred every year since its release in 2018. These changes are detailed in a GS Report which can be downloaded at https://digs.geoscience.nsw.gov.au/report/R00055828. Changes to the current version (v. 2.4) are detailed below:

What's new in Version 2.4 (May 2024)?

• Leucitite volcanic suites, western NSW – updated the “Dominant Lithology” attribute of all Cenozoic age leucitite volcanic rocks of western New South Wales from "Igneous Rock, other" to the more accurate “Foid-bearing extrusive rock”.

• Davis Creek Syncline, New England Orogen – the Davis Creek Syncline (centred at 151.124854° -32.141107° – GDA94) was misaligned in previous versions of the Seamless Geology, plotting ~200 m south of its correct location. This has been fixed in version 2.4.

• Duplicate fold axes, Werrie Basin area, New England Orogen – deleted several duplicate fold axes around 150.796725° -31.700391° – GDA94. Named the large fold in this area the ‘Chilcotts Creek Anticline’ after Roberts (2001).

• Lightning Ridge update - the boundary between the Cretaceous Rolling Downs Group outcrop / subcrop areas and the Quaternary black soil alluvial plains (Marra Creek Formation) has been significantly upgraded in this version of the Seamless Geology using data from Burton et al. (2023). This study involved reinterpreting and re-digitising this boundary at 1:10,000 scale using the best available ADS imagery in combination with 1–2 m DEM data.

• Lake Cowal geology upgrade – the mapping of the Lake Cowal Volcanic Complex was significantly upgraded based on several recent publications and publicly available theses.

• Cadia Valley geology upgrade – the geological mapping of the Cadia Valley (host to the Cadia–Ridgeway Au–Cu porphyry-related deposits) was significantly upgraded based on several recent publications and publicly available theses.

• Llandovery–Wenlock sequences of the Angullong Syncline and Bridge Creek areas – richly fossiliferous early Silurian sequences of the Ashburnia Group and Waugoola Group southwest of Orange were updated based on the detailed mapping of Jenkins (1973, 1978).

• Gidginbung Volcanics and Rain Hill Monzodiorite – the Gidginbung Volcanics was moved from the Lake Cowal Volcanic Complex into "Ungrouped Ordovician igneous units", and the Rain Hill Monzodiorite (near Barmedman) was added to the Seamless Geology based on the work of Mowat (2003) and Goesch (2011).

• Gunningbland Formation and Billabong Creek Formation, Gunningbland area – the geology of the Gunningbland area was updated from figures 1 and 2 of Zhen et al. (2023), which outline several newly documented areas of outcrop and changes to several areas from Gunningbland Formation – limestone to Billabong Creek Formation (based on faunal evidence).

• Benolong Volcanic Suite (Permian–Mesozoic Igneous Province) – the peralkaline Mesozoic volcanic rocks and intrusions around Toongi (22 km south of Dubbo), previously undifferentiated, have been placed in the newly-defined Benolong Volcanic Suite (Tbv), which comprises four constituent units. Updated boundaries for many of the intrusions have been interpreted based on radioelement imagery, DEM data and ADS imagery, resulting in changes to fours layers: Cenozoic Sedimentary Province (CSP), Permian–Mesozoic Igneous Province (PMIP), Permo–Triassic Basins (PTB), and the Lachlan Orogen (LAO).

• Sydney Basin – major review and update – the mapping of the western margin of the Sydney Basin was substantially updated for version 2.4 of the Seamless Geology. Nine 1:50,000 provisional geology maps from the 1960's and early 1970's were added to the dataset. In areas not covered by the 1:50,000 geology series maps, the updated Permo-Triassic geology was re-digitised from the original (approximately 1:20,000 scale) compilation maps of the Warragamba Catchment geology maps (McElroy and Relph, 1958b) combined with interpretation from 2 m DEM imagery and 5 m contours. The mapping of the Narrabeen Group in the Northern Beaches area (Sydney) and the northern Illawarra escarpment was updated based on published and unpublished data, and several errors in previous versions of the Seamless Geology were corrected. The geology of the Lapstone Structural Complex, west of Penrith, was updated using mapping from Fergusson and Hatherley (2023). The mapping of the Wolgan Valley Inlier (north of Lithgow) was updated based on unpublished mapping by Colquhoun (1991). The Marrangaroo Formation (Pibm, previously Marrangaroo Conglomerate) was added around its type area near Marrangaroo Railway Station, 5 km northwest of Lithgow based on published and unpublished sources. Detailed (1:12,500 scale) mapping (Figure 43) of the Illawarra Coal Measures between Ben Bullen and Portland by Dove (1987) was digitised and added to the Seamless Geology to join to the above-mentioned 1:50,000 scale mapping.

• Quarry Creek area – Waugoola Group and Mirrabooka Formation – mapping of the richly fossiliferous limestone and shale sequences in the Quarry Creek area (22 km west of Orange) was substantially updated based on two Honours theses and several published maps.

• Borenore Limestone – the main area of outcrop of the Borenore Limestone (around Borenore Caves, 15 km west-northwest of Orange) was missing from previous versions of the Seamless Geology. The unit has been added to the dataset at version 2.4 based on the mapping of Partridge (1967) and Krynen et al. (1997).

• Mount Halfway Volcanics units – the units Dhhh and Dhhl from the Mount Allen 1:100,000 Geological Sheet (Scheibner, 1985) were added to version 2.4 of the Seamless Geology. These two units had been previously combined into a generalised rhyolite lava unit.

• Curnamona Province – line attribute update – many of the geological boundaries, faults, and fold axes of the Curnamona Province were attributed as “accurate” despite many being under Cenozoic cover. At version 2.4 of the Seamless Geology, linework under shallow Cenozoic cover which was attributed as “accurate” has been changed to “concealed” or “inferred”, resulting in 9,848 linework attribute changes.

• Fault attributes – New England Orogen, Lachlan Orogen, Delamerian Orogen and Curnamona Province layers- the fault attributes “Fault Dip Direction”, “Gravity Visibility” and “Magnetic Visibility” had been accidentally removed from large areas of the orogenic belt layers and the Curnamona Province layer. These attributes were replaced in version 2.4 of the NSW Seamless Geology using various backups of the fault attributes data.

• Structural data – Merimbula Group (and adjacent units) – Five hundred and twenty-six structural points were added to the Lachlan Orogen layer from spreadsheets supplied by Chris Fergusson from the publication Fergusson (2023) on structure of the Merimbula Group.

• Pokolbin Inlier, Mount View area – Recent feedback from Ed Willey and Chris Fergusson has pointed to several small errors in the mapping of the Pokolbin Inlier, including inaccurate mapping of the base of Narrabeen Group and the absence of several marker units in Seaham Formation. These have been added to the Seamless Geology at version 2.4. In addition, 63 structure points were added to this area from the earlier Honours mapping of Brakel (1967).

• General GSL_Stratigraphy changes - numerous code changes, spelling mistake corrections, and formalising of names were made to the GSNSW's GSL_stratigraphy database. These have flowed through to the Seamless Geology dataset at version 2.4.

• Bergalia Formation – the Oligocene Bergalia Formation of the NSW South Coast was present in both the Cenozoic Igneous Province and Cenozoic Sedimentary Province layers in previous versions of the Seamless Geology. It has now been placed in the Cenozoic Igneous Province layer exclusively. Although the unit is predominantly sedimentary, it largely underlies the Cenozoic basalts of the area and is closely related to them.

dataset

ISO 19139 Geographic Information - Metadata - Implementation Specification ISO 19139 Geographic Information - Metadata - Implementation Specification

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