Abstract

The Paleoproterozoic Westmoreland region is located 1250 km southeast of Darwin. The Westmoreland region is flanked on the southeast by the Paleoproterozoic Mt Isa Inlier and the Neoproterozoic South Nicholson Basin and in the northwest it is overlapped by Mesoproterozoic sediments of the McArthur Basin. The northern and southern ends of the McArthur basin share many geologic attributes including correlative stratigraphic rock types, which suggests that there is potential for unconformity-related uranium deposits in the southern McArthur basin and adjacent Westmoreland region. In fact, over fifty occurrences of uranium (some with minor gold) and copper mineralisation have been recorded in the Westmoreland region. Fluid inclusion studies have been carried out on selected uranium and copper prospects on the Northern Territory side of the Westmoreland region. Four types of inclusions have been observed, (Type A) Vapour-rich inclusions containing 30 100 vol.% vapour. Varying amounts of CO2 ± N2 ± CH4 have been detected in these inclusions, (Type B) Liquid-rich inclusions with up to 30 vol.% vapour, (Type C) Liquid-only inclusions, and (Type D) Three-phase (vapour + liquid + solid) liquid-rich inclusions containing a small daughter crystal. Type A, vapour-rich inclusions and some Type B, liquid-rich inclusions homogenised over the range 171 to 385 °C and are thought to be related to early metamorphic events. Other Type B and Type D inclusions typically homogenised between 100 and 240 °C with a mode around 120 °C, while the presence of liquid-only inclusions suggests trapping at temperatures below 50 °C. Eutectic melting temperatures indicate the presence of CaCl2 in the fluids but final melting temperatures show the presence of both high and low salinity brines. This suggests mixing between saline basinal fluids and low salinity meteoric fluids that continued down to temperatures below 50 °C.
Google map showing geographic bounding box with values North bound -15.0 East bound 142.0 West bound 134.0 South bound -23.0
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Product Type/Sub Type

nonGeographicDataset - PowerPoint

Constraints

license
Creative Commons Attribution 3.0 Australia Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2010

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

Keywords

PowerPoint
fluid inclusions
geoscience
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-15.0
East bound
142.0
West bound
134.0
South bound
-23.0

Lineage

Unknown

Digital Transfer Options

onLine

DISTRIBUTION Format

pdf

Distributor

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

Metadata File Identifier

a05f7892-f969-7506-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 Date Stamp

2010-09-17

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
Downloads
For information on acquiring this product,
please contact the Geoscience Australia Sales Centre via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).

Please note that support hours are 9 am to 5 pm weekdays