Exploration for porphyry-style copper mineralisation near Llandeloy
Exploration for porphyry-style copper mineralisation near Llandeloy
Exploration for porphyry-style copper mineralisation near Llandeloy
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BOREHOLE 7 Registration Number SM 82NE/8<br />
Grid Reference SM 8527 2915<br />
Height above O.D. 123.7 m<br />
Casing to 8.23 m<br />
Recent<br />
Description of strata<br />
SOIL:<br />
Pleistocene<br />
CLAY WITH PEBBLES: brown sandy clay, struc tureless<br />
with mainly black shale pebbles to 1.07; laminated<br />
and silty with sparse pebbles below with pebbly<br />
band 1.22-1.30<br />
CLAY: regularly alternating brown-clay 2-3 mm,<br />
greyish mottled clay 1.1-1.5 cm with local irregularities.<br />
Beds coarse lithic muddy sand below 1.83. Gravel<br />
bed ?0.36 cm thick at 4.94<br />
QUARTZ-MICRODIORITE: deeply weathered with<br />
sparse plagioclase, amphibole phenocrysts<br />
ACID LAVA: deeply weathered, badly broken core,<br />
much lost<br />
QU ARTZ-MICRODIORITE: medium-grained with sparse<br />
plagioclase and hornblende phenocrysts. Deeply<br />
weathered. Network fracturing 12.75-14.83 and locally<br />
elsewhere. Quartz veins up to 1 cm at intervals,<br />
some with pyrite. Quartz-feldspar, epidote and<br />
chlorite veinlets uncommon. Locally epidote-pyrite<br />
veins. Pyrite, disseminated and in veinlets is locally<br />
abundant; especially 15.74, 16.96-18.28<br />
CLAY GOUGE:<br />
QU ARTZ-MICRODIORITE: as above. Xenoliths<br />
microdiorite and other rocks in upper parts.<br />
Glomeroporphyritic below 21.00. Patchy carbonate<br />
alteration. Network fractures throughout. Quartz<br />
veinlets common. Pyrite abundant in veinlets and<br />
disseminated, locally with quar tz-chlorite veinlets.<br />
Local carbonate, epidote veinlets and silicification<br />
QU ARTZ-MICRODIORITE: as above. Sharp intrusive<br />
upper contact. No xenoliths. Downward increase in<br />
porphyricity. Numerous epidote veinlets, quartz<br />
veinlets not common. Pyrite mainly in fractures<br />
23.00-24.08, 24.47-24.94<br />
QUARTZ-MICRODIORITE: as above. Sharp intrusive<br />
upper contact, xenolithic. Network fractures in<br />
places. Abundant veinlets quartz, carbonate,<br />
chlorite 27.30-27.47. Intense epidotization locally<br />
25.48 to base. Pyrite abundant disseminated and in<br />
fractures 25.68-26.02<br />
CLAY GOUGE:<br />
QU ARTZ-MICRODIO RITE: as above. Epidotization<br />
increases downwards. Pyrite veins and disseminated<br />
END HOLE