『Abstract
Hydrothermal ore deposits form by enriching elements and minerals
from background values to very high concentrations in small volumes
of the crust. The de Wijs model provides a simple and widely used
mathematical description of this process; however, it does not
account for the increase in density which generally attends the
formation of high specific gravity minerals in many mineral deposits.
We present an expanded version of the de Wijs model to investigate
the distribution of ore tonnage as well as grade. The expanded
model generates a log-normal relationship between ore tonnage
and grade. Continuous multifractal analysis of results from the
new model using the method of moments technique predicts that
ore grades are multifractal (as in the original de Wijs model)
but that ore tonnage values are not multifractal. Production data
from vein-hosted gold deposits in the Archaean Zimbabwe craton
display the log-normal relationship between ore tonnage and grade,
the multifractal nature of ore grade, and the nonmultifractal
nature of ore tonnage, which are generated in the expanded de
Wijs model.
Keywords: Geostatistics; Gold; Mineral deposits; multifractal
analysis; Resources; Zimbabwe』
Introduction
Construction of the expanded de Wijs Model
Determining multifractality
Vein-hosted gold production data
Results
Discussion
Conclusions
Acknowledgements
References