『Abstract
Mineralization in hydrothermal ore systems has proximity, association
and abundance relationships with fluid pathways (e.g. faults and
lithological contacts) based on the concept of deformation-induced
permeability being localized along such features. To empirically
calibrate the abundance relationship between these features and
gold mineralization, a measure known as geological complexity
has been quantified. A fractal dimension representing the degree
of geological complexity is evaluated using a box-counting method
on the combination of faults and lithological contacts on a series
of maps over the Kurnalpi Terrane of the Archaean Yilgarn Craton.
Using multi-scale geological datasets from the Kurnalpi Terrane,
we show that geological complexity and its relationship to known
occurrences of orogenic gold mineralization varies depending on
scale and degree of interpretation of the maps analyzed. In terms
of scale, stronger correlations are observed for higher resolution
‘outcrop’ geological and structural maps. Even when the percentages
of outcrop was taken into consideration, the higher resolution
maps still showed greater correlations between geological complexity
and gold mineralization. Differing solid geological interpretations
at the same scale significantly affect the degree of quantified
geological complexity and its correlation with known gold mineralization.
The study results also illustrate a negative correlation between
gold mineralization and gradients in the geological complexity.
This outcome is contrary to results obtained by previous workers,
and indicates that geological complexity, rather than complexity
gradients, is useful as an input predictor map for prospectivity
analysis and exploration targeting in the Kurnalpi region and
other regions containing similar orogenic gold systems. Furthermore,
the results indicate that interpreted solid geology maps, while
critical for manual conceptual targeting, nay actually be less
effective than outcrop maps as a predictive layer in automated
conceptual and empirical prospectivity analysis.
Keywords: Fractal dimension; Geological complexity; Kurnalpi Terrane;
Orogenic gold; Scale dependency; Tilgarn Craton』
1. Introduction
2. Geology and gold mineralization of the Kurnalpi region
3. Data and methods
4. Results
5. Discussion
6. Conclusions
References