『Abstract
This paper describes the approach to, and outcomes of, a manual
analysis (i.e., a cognitive assessment of spatial and non-spatial
data) of the uranium potential of 90 geological regions in Australia.
For this analysis, the 14 principal uranium deposit types recognized
by the International Atomic Energy Agency were grouped in six
uranium system models (i.e., surficial, sedimentary, igneous-related,
metamorphic/metasomatic, unconformity-related, and vein-related
uranium systems) on the basis of similar genetic processes, environments
of ore formation and ingredients mappable at the regional to continent
scale. The newly proposed uranium systems models are structured
according to the mineral systems approach and focus on the critical
mineralization processes that must occur for a uranium deposit
to form in a particular region. Our manual prospectivity analysis
employed this approach to assess the probability of the critical
genetic processes having occurred in each geological region. In
this semi-quantitative, probabilistic evaluation, technical, quality
and opportunity ranking schemes were used to rank each geological
region based on the probability of occurrence of and potential
for high-quality uranium deposits and opportunity for securing
prospective ground. Based on this assessment, the geological regions
with the greatest potential for discovery of potentially recoverable
uranium resources are the Ashburton, Broken Hill, Litchfield,
McArthur, Money Shoal, Murphy, Paterson, Pine Creek and Northeast
Tasmania regions (i.e., quality ranking of 10.0), the Gawler and
Polda regions (i.e., 9.0), and the Amadeus, Georgetown, Stuart,
Tanami regions (i.e., 8.1). Most of these regions contain known
unconformity-related or sandstone-hosted uranium deposits, although
some of them are pure conceptual plays that have received relatively
little attention in terms of uranium exploration. Maps based on
the numerical output of the prospectivity analysis helped to inform
area selection decisions and detailed follow-up studies, and focus
time and resources. The template developed in this study can easily
be modified to suit prospectivity analyses for other metals or
a similar investigation in another country. As illustrated in
Part II, the best possible approach to a complex, continent-wide
prospectivity analysis is to harness the strengths of both manual
and automated (i.e., sophisticated computational techniques applied
to spatial data) approaches as these methodologies essentially
address each other's limitations.
Keywords: Area selection; Conceptual targeting; Deposit classification
scheme; Mineral systems approach; Prospectivity analysis; Uranium;
Australia』
1. Introduction
2. Manual uranium prospectivity analysis
2.1. Literature review
2.2. Rationale and construction of uranium systems models
2.3. GIS database
2.4. Scope, design, conduct and results of the prospectivity
analysis
3. Case studies
3.1. Surficial uranium systems
3.1.1. Yilgarn Region (Western Australia)
3.1.2. Musgrave Region (Northern Territory, South Australia,
Western Australia)
3.2. Sedimentary uranium systems
3.2.1. Eromanga Region (New South Wales, Northern Territory,
Queensland, South Australia)
3.2.2. Carnarvon Region (Western Australia)
3.3. Unconformity-related uranium systems
3.3.1. Pine Creek Region (Northern Territory)
3.3.2. King Leopold Region (Western Australia)
4. Discussion
4.1. New uranium deposit classification scheme
4.2. GIS-assisted manual versus GIS-driven automated prospectivity
analysis
4.3. Scope of the manual uranium prospectivity analysis
5. Conclusions
Acknowledgements
References