Geological Survey

Geological mapping

Overview

The Geological Survey of NSW (GSNSW) carries out geological mapping which involves identifying and recording the character and distribution of rock units at or near the Earth's surface. The surface distribution, orientation and inter-relationship of the various rock units, allow geologists to infer their three-dimensional arrangement, and to determine the structure and composition of the upper part of the Earth's crust.

The geology of the surface and near-surface of the Earth determines the potential availability of mineral, coal, petroleum, water and construction material resources. Geological mapping also provides information that is critical for land assessment, engineering construction, environmental management, and natural hazard risk assessment. This knowledge is essential to sustain modern society.

Geological Maps are published in 1:500 000, 1:250 000, 1:100 000 and 1:25 000; series and are accompanied by comprehensive explanatory notes. Geophysics is integrated with the geology to produce geophysical-geological interpretation maps and to generate 3d models of geological bodies and structures.

Geological mapping data is also integrated with geophysical datasets, mineral occurrences, geochemistry, age dating and exploration and tenement datasets to form comprehensive geoscience data packages for many areas throughout the State.

Geological mapping activities uses specialist geoscientific services, such as petrological and palaeontological advice. The W B Clarke Geoscience Centre houses the state's fossil, rock and economic mineral reference collections at Londonderry. Together with the Core Library and the Auscope National Virtual Core Library, this centre holds an invaluable wealth of geoscience reference data as well as providing analytical services.

Current activities

Current mapping projects being conducted or being completed are over the Koonenberry, Broken Hill, Cobar, Goulburn, Braidwood and Thomson project regions. Geophysical-geological interpretation maps are being completed over a number of 1:250 000 map sheet areas in the northwest and southwest of NSW. A description of the mapping projects follow.

The Koonenberry Belt in northwest NSW includes parts of the Delamerian and Thomson orogens to the east of the Curnamona Province. This under explored terrane has great potential for undiscovered mineral deposits. Bulletin 35 'Explanatory notes for the Koonenberry Belt geological maps' is available for purchase in hardcopy. Four 1:25 000 geological maps of inliers, are completed. Twelve 1:100 000 geological maps, four 1:100 000 regolith maps and two 1:250 000 solid geology maps are in production.
The Thomson Project area, which underlies the Channel Country in the northwest, is a major greenfield region in NSW. It has potential for arc and ocean-crust related gold and base metal deposits while the area to the south of the orogen may have potential for Mississippi Valley style zinc deposits.
Mapping in the Cobar region has produced preliminary Sussex and Byrock 1:100 000 geological maps.
The focus of the Goulburn mapping is the publication of Goulburn Explanatory Notes, and release of the Goulburn 1:250 000 Solid Geology Map (2 sheets) and the six constituent 1:100 000 map sheets.
Geological mapping of the Braidwood 1:100 000 Geological Sheet and a preliminary 3d model have been completed.
The aim of the Tasmanides Project, formerly a collaborative project with pmd*CRC, is to construct a 3d model of the Tasmanides so as to understand the fundamental controls on location of major ore deposits and to assist the mineral exploration industry to predict and discover new world class ore bodies in Southeast Australia. A preliminary series of internally-consistent east-west sections has been completed with the aim to construct a 3d model for the East Lachlan.
The Broken Hill Interpretive Mapping Project aims to interpret the stratigraphy of the Proterozoic in the Broken Hill region. One of the products will be a revised 1:100 000 interpretive stratigraphic map, based on the latest geophysics and existing detailed GSNSW 1:25 000 lithological mapping. The project is one of several under the auspices of the Broken Hill Exploration Initiative.
The Greater Sydney Region Geoscience: Audit and Gaps Analysis Report (GS2007/214 in DIGS) is a study that extends from Port Stephens in the north, to Batemans Bay to the South, and Katoomba to the west. It identified the Moss Vale 1:100 000 Geological Sheet as a priority to be mapped, so work on this sheet began in February 2007 and is soon to be completed.
Geophysics is being integrated with geology to produce geophysical-geological interpretation maps.
Geological mapping datasets were consolidated for the COGENT II project which aims to provide easy access to all validated, non-confidential, corporate, geoscientific data stored by the GSNSW and Coal and Petroleum branches
Other projects include the National Geochemical Survey of Australia (NGSA) which is a project being undertaken by Geoscience Australia (GA) in cooperation with the Australian state and territory geological surveys.

Current geological mapping projects

Current mapping project areas

Current geophysical-geological interpretation maps

The 1:250 000 scale geophysical-geological interpretation maps are Milparinka, Cobham Lake, Bourke, Louth, White Cliffs, Urisino, Yantabulla, Enngonia, Hay, Balranald, Deniliquin, Booligal, Ana Branch and Pooncarie. Parts of Broken Hill, Cobham Lake and Milparinka have been completed to a provisional level under the Broken Hill Interpretive Geological Mapping Project. See also Geophysical-geological interpretation maps.

For further information please contact the Geological Mapping Team.

(Last updated on 18/08/2011)