Exploration for porphyry-style copper mineralisation near Llandeloy

1 Quartz '
1 microdiorites
, BH2 0.
/ ,! Quartz
microdiorites
.' I BH2
A lgneous rocks from surface exposures
Igneous rocks from boreholes
X Quartzwacke
0 Igneous rocks with K-feldspar alteration
I A
Figure 38 Examples of ratio plots for relatively mobile (Sr) and immobile elements (Zr, Ti and Y)
propylitic alteration, which is concentrated in breccia
zones, may be associated with increases in Cu, Zn, Mn
and Ca and depletion in Rb and Ba, but the majority of
any compositional changes are caused by the
accompanying sulphide mineralisation.
Mineralisation, with the exception of a brecciated
zone between 105.61 and 106.20 m, is weak in the
sedimentary rocks of borehole 8. Cu levels are lower
than those in any of the other boreholes with the
exception of the lower part of borehole 1. There is no
general correspondence of high Cu levels with intrusion
breccias. There is no substantial enrichment in any of
the other chalcophile elements determined, 45 ppm Pb in
a veined magnetite sandstone is the only outlying high
result. Some of the highest Fe results in the quartz
wackes, for example 8.6% Fe between 99 m and 100 m
and 8.1% Fe between 105.61 m and 106.20 m, correspond
with zones of relatively heavy pyrit isation and intrusion
breccias. W levels (up to 9 ppm) are higher in the
sedimentary than in the igneous rocks and much higher