Abstract

Regional airborne magnetic and gravity data and field observations have been used to define four geophysical domains in the Lachlan Fold Belt of New South Wales. Each has a different pattern of anomaly trend and amplitude. Three domains correspond with provinces containing rocks of similar lithology and age; the other corresponds with the Darling Basin. The magnetic data highlight minor variation in magnetite abundance, chiefly in igneous rocks, and, across the region, reflect slight differences in magma composition, structural trends, and possibly also style of volcanism and sedimentation. The gravity data also delineate the same structural trends and some major lithological variations. The boundary of the Darling Basin is gradational. The other domain boundaries are sharp, but with no evidence of major faulting. Within the geophysical domains a classification of magnetic anomalies by length, width, and amplitude appears capable of distinguishing between the various sources, thereby providing a useful mapping tool in regions with surficial cover. Circular anomalies of largest extent occur over granitoids, the smallest over small pipes and veins, and the intermediate size over basic and ultrabasic stocks. Elliptical anomalies are associated with magnetic granitoids and some basic and ultrabasic bodies. Sources of narrow anomalies include basic dykes, steeply tilted Palaeozoic lavas, ignimbrites, and serpentinites. Sources of complex zones include Tertiary basalt flows, piles of basic and intermediate lavas surrounding small intrusions, and some inhomogeneous granitoids. The regional gravity data reflect features with very large dimensions or large density contrasts. A major north-northeast trending Bouguer anomaly low corresponds with the Eastern Highlands, a region of high relief, thick crust, and extensive granitoids. A narrower low corresponds to another belt of granitoids trending north-northwest from Holbrook to Cobar. Small-scale gravity features include the Coolac Serpentinite and its associated basic rocks, the Mid-Silurian to Mid-Devonian Hill End Trough, and numerous regions of Late Devonian quartzose sedimentary rocks.
Google map showing geographic bounding box with values North bound -29.0 East bound 151.5 West bound 144.0 South bound -37.0
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Product Type/Sub Type

nonGeographicDataset

Constraints

Creative Commons Attribution 4.0 International Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

1980-01-01T00:00:00

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

GA Catalogue Number

81052 Product http://www.ga.gov.au/metadata-gateway/metadata/record/81052/

Keywords

GA Publication
Journal
NSW
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-29.0
East bound
151.5
West bound
144.0
South bound
-37.0

Lineage

Unknown

Digital Transfer Options

onLine

Distributor

Role
distributor
Organisation Name
Commonwealth of Australia (Geoscience Australia)
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Source Description

Source data not available.

Metadata File Identifier

fae9173a-6ff9-71e4-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Commonwealth of Australia (Geoscience Australia)
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
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