Abstract. The aim of this study is to delineate and identify various mineralized zones
and barren host rocks based on surface and subsurface lithogeochemical data
from the Pulang porphyry copper deposit, southwestern China, utilizing the
number–size (N-S), concentration–volume (C-V) and power-spectrum–volume
(S-V) fractal models. The N-S model reveals three mineralized zones
characterized by Cu thresholds of 0.28 % and 1.45 %: <0.28 %
Cu represents weakly mineralized zones and barren host rocks,
0.28 %–1.45 % Cu represents moderately mineralized zones, and
> 1.45 % Cu represents highly mineralized zones. The results
obtained by the C-V model depict four geochemical zones defined by Cu
thresholds of 0.25 %, 1.48 % and 1.88 %, representing nonmineralized
wall rocks (Cu<0.25 %), weakly mineralized zones
(0.25 %–1.48 %), moderately mineralized zones (1.48 %–1.88 %) and
highly mineralized zones (Cu>1.88 %). The S-V model is used by
performing a 3-D fast Fourier transformation of assay data in the frequency
domain. The S-V model reveals three mineralized zones characterized by Cu
thresholds of 0.23 % and 1.33 %: <0.23 % Cu represents
leached zones and barren host rocks, 0.23 %–1.33 % Cu represents
hypogene zones, and >1.33 % Cu represents supergene enrichment
zones. All the multifractal models indicate that high-grade mineralization
occurs in the central and southern parts of the ore deposit. Their results
are compared with the alteration and mineralogical models resulting from the
3-D geological model using a log-ratio matrix. The results show that the S-V
model is best at identifying highly mineralized zones in the deposit.
However, the results of the C-V model for moderately and weakly mineralized
zones are also more accurate than those obtained from the N-S and S-V models.
Geochemical Characteristics of Granitoids of the Erdenet Porphyry Copper Deposit, Mongolia
