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 4 Registration Number SM 82NE/6<br />
Grid Reference SM 8566 2874<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:<br />
FELDSPAR SAND AND CLAY: deeply weathered,<br />
regular alternation of sand 1-2.5 cm, clay 0.3-1.0 cm<br />
to 2.23; irregular below<br />
GRAVEL: heterolithic<br />
FELDSPAR SAND AND CLAY: regular bedding as<br />
above. Some beds gravel with diorite pebbles only.<br />
Thick clay beds below 7.77<br />
MICRODIORITE: medium grained, feldspathic with<br />
sparse phenocrysts, feldspar and amphibole up to 5 mm.<br />
Deeply weathered to 15.24. Quartz veins up to 2 cm<br />
at intervals with some adjacent silicification. Chlorite<br />
veinlets between 22.00-24.00; epidote veinlets mainly<br />
below 22.00; some epidotisation 17.30, 22.00. Pyrite<br />
disseminated and in fractures moderately abundant<br />
11.36-11.50, minor below, but in veins with gangue<br />
at intervals. Chalcopyrite below 22.00<br />
MICRODIORITE: as above. Sharp, irregular intrusive<br />
contact 30" at top. Porphyritic marginal phase to<br />
25.59. Carbonate alteration, some epidote veinlets.<br />
Quartz veins with pyrite and chalcopyrite 25.75-25.85.<br />
Also disseminated pyrite<br />
MICRODIORITE: as above. Sharp upper contact 45O,<br />
porphyritic to 26.40. Patchy texture below 27.31,<br />
mainly due to recrystallization. Sparse veining.<br />
Pyrite rare disseminated, in veinlets with epidote<br />
27.31-27.85. Chalcopyrite at 27.84<br />
MICRODIORITE, porphyritic: fine-medium grained,<br />
greyish-green with phenocrysts feldspar 2 mm,<br />
hornblende 5 mm. Patchy carbonate alteration.<br />
Xenoliths up to 6 cm at 29.64, 31.78. Pyrite sparsely<br />
disseminated; com monly in veins with quartz,<br />
feldspar, chlorite, epidote to 32.80 only<br />
QU ARTZ-DIORITE: coarse-grained, feidspathic;<br />
sparsely porphyritic with plagioclase to 2 mm,<br />
hornblende to 5 mm increasing in proportion downwards.<br />
Sharp irregular upper contact with upward<br />
penetrating flames. Basic xenoliths at intervals;<br />
pegmatitic patch 34.15. Quartz veins rare, Epidote,<br />
chlorite, quartz, carbonate, feldspar veins more<br />
common; local epidotisation. Patchy recrystallization<br />
and textural variation. Pyrite in veinlets and<br />
disseminated only at 34.65, 35.90, 37.85-38.02<br />
END OF HOLE