Exploration for porphyry-style copper mineralisation near Llandeloy

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APPENDIX 1 ABBREWATEI) BOREHOLB LOGS FROM LLANDELOY The complete logs have been lodged with the Welsh Office of BGS, Unfarian, Aberystwyth. All boreholes were drilled using a JKS 300 rig. Boreholes 1-7 were vertical and BQ core was retrieved throughout. Borehole 8 was inclined 60" to 180' (True); BQ core was retrieved to 72.26 m, AQ below. All measurements of inclination given below relate to the length of the core- BOREHOLE 1 Registration Number SM 82NW/1 Grid Reference SM 8446 2809 Height above 0.0. 89.77 rn Casing to 8.38 m Description of strata OPEN HOLE VOLCANIC BRECCIA: angular fragments quartzose sandstones, volcanic rocks up to 3 cm. Beds coarse tuff up to 33 cm thick. Network veinlets quartz; some sericite veinlets. Pyrite sparsely disseminated QUARTZ: MICROTONALITE, porphyritic: deeply weathered, with white altered feldspar phenocrysts 3 mm, sparse amphibole phenocrysts. Xenoliths volcanic rock at 6.70. Network fractures below 6.97; breccia veinlet at 7.28. Pyrite sparse, disseminated; totally hematised in hair fractures VOLCANIC BRECCIA: As above MICROTONALITE, porphyritic: as above; less weathered. Sharp upper contact 3OU, basal contact irregular, sharp. Some quartz veinlets, sericite and chlorite in fractures. Pyrite sparse and disseminated ACID VOLCANIC: fine-grained with small feldspar phenocrysts, crude banding. Brecciated and veined by quartz, chlorite MICROTONALITE, porphyritic: as above. Flames penetrate upper unit; xenoliths at top. Network fracturing, plentiful quartz veinlets, some 35O-40". Pyrite sparse, disseminated CRYSTAL TUFF: weathered. Quartz veinlets; quartz- chlorite vein 3 cm, 40". Network fractures QUARTZ: anastomosing veins with crystal tuff ACID VOLCANIC: as above CLAY GOUGE: MICROTONALITE, porphyritic: as above. Quartz veins with pyrite 2-30 mm. Pyrite disseminated, sparse, increasing downwards ACID VOLCANIC: as above. Brecciated at top. Network fractures, sericitised. Pyrite sparsely disseminated, hematised in 1 cm vein at 21.91 VOLCANIC BRECCIA: clasts mudstone, sandstone, sericitised, 4 cm long. Veinlets quartz, chlorite. Pyrite sparse disseminated, local concentrations, hematised in network fractures
CRYSTAL TUFF: as above VOLCANIC BRECCIA: as above CLAY GOUGE: VOLCANIC BRECCIA: as above MICROTONALITE, porphyritic, as above. Pyrite sparse, disseminated SILTSTONE: thin beds, sandy and pebbly MICROTON ALITE, porphyritic: as above CLAY GOUGE: with lost core MICROTONALITE, porphyritic: as above, unweathered below 26.91. Phenocrysts feldspar 8 mm, amphibole, rare quartz in greyish-green matrix. Upper contact sharp, horizontal. Quartz veins at intervals. Pyrite sparse, disseminated with concentrations below 26.92 MICROTONALITE, porphyritic: as above, sharp upper contact 50'. Network fractures at top, below 28.60, 29.28-29.64 with quartz veinlets, chlorite. Pyrite abundant disseminated to 28.00, 29.28-29.64 and else where, also veins. Veins porphyritic microdiorite below 29.80 richly pyritic MICRODIORITE, porphyritic: phenocrysts feldspar up to 8 mm, amphibole to 1 cm in green matrix. Sharp upper contact. Pyrite plentiful, disseminated and in hair fractures QUARTZ-MICRODIORITE: sparse phenocrysts feldspar, amphibole in medium-grained feldspathic rock. Some xenoliths sedimentary rocks, diorite. Upper contact broken. Grain-size reduces below 33.19; rock is porphyritic to 33.93, fine-grained non-porphyritic to base. Pyrite disseminated and in fractures with chlorite, locally abundant especially 3 1.80-32.47 MICROTONALITE, porphyritic: as above, variable concentration phenocrysts. Network fractures, breccia with chlorite veinlets at intervals 35.09-38.27, 42.97-44.91. Quartz veinle ts, rare carbonate. Epidote below 43.27. Pyrite disseminated, concentrated in fracture zones END HOLE
Page 1:
Natural Environment Research Counci
Page 5:
Report No. 78 @ Crown copyright 198
Page 9 and 10:
SUMMARY REGIONAL STUDIES Intrusive
Page 11 and 12:
SUMMARY Geological, geochemical and
Page 13 and 14: concluded that except for Zn the re
Page 15 and 16: The only rock containing evidence o
Page 17 and 18: Table 3 Analyses of miscellaneous r
Page 19: - 28 St. Brides Bay -
Page 22 and 23: Hercynian orogenies (M. 3. Arthur,
Page 24 and 25: Figure 14 Location of soil anomalie
Page 26 and 27: producing a very limited dispersion
Page 28 and 29: -1 00- Contours of VLF horizontal i
Page 30 and 31: area and periglacial and glacial de
Page 32 and 33: the Brunel Beds or the Tetragraptus
Page 34 and 35: contains sparse subhedral plagiocla
Page 36 and 37: There is some variation in the alte
Page 38 and 39: The cause of other isolated weak Cu
Page 40 and 41: j Table 9 Summary of analyses of in
Page 42 and 43: increase the Zr content. The divisi
Page 44 and 45: variation between pu8M microdioritn
Page 46 and 47: T/I~~/~~IPYS openjoi~~tcd limestone
Page 48 and 49: Table 13 Summary statistics for sed
Page 50 and 51: than average values quoted for sand
Page 52 and 53: Introduction The main geophysical m
Page 54 and 55: Figure 42 Contour map of apparent r
Page 56 and 57: Figure 45 Contour map of tow magnet
Page 58 and 59: Pigum? 47 Cumulative f reguency plo
Page 60 and 61: it to this late propylitic alterati
Page 62 and 63: HOLWSTER, V.F. 1974. An appraisal o
Page 66 and 67: BOREHOLE 2 Registration Number STvI
Page 68 and 69: BOREHOLE 3B Registration Number SM
Page 70 and 71: BOREHOLE 5 Registration Number SM 8
Page 76 and 77: SANDSTONE: as above CLAY GOUGE: SAN
Page 78 and 79: --- APPARENT ESISTIVITY pa IN OHM M
Page 80 and 81: APPARENT ESISTMTY H Bbs ys 06 q6 CH
Page 82 and 83: z ~ l ~ ~ ~ l ~ l . ~ l ~ , ~ l l A
Page 84 and 85: z ~ 1 ~ 1 ~ 1 ~ 1 ~ 1 APPARENT FEJS
Page 86 and 87: z ~ l $ l l l l l ~ l l ~ l l l l ~
Page 88 and 89: MAGNETIC FELD IN NAFTESLA Y /-*-.-.
Page 90 and 91: !IN@ a 8 g e s s I! s F N : , S ? I
Page 92 and 93: ~ N & E e 8 g B 8 8 7 a F N . S ~ 9
Page 94 and 95: PHYSICAL PROPERTY MEASUREMENTS ON B
Page 96 and 97: Borehole 8 (diameters of core 9-72
Page 98 and 99: APPENDIX 5 COMPUTER MODELLING OF AE
Page 101 and 102: RMS RESID - 6.53 FLU. PT ELEV ORS n
Page 103 and 104: MRGNET I C: TIJTERF'HFTAT 1014 . .
Page 105 and 106: ANU.YSB OF BOLPROLB CORE& TRACE ELE
Page 107 and 108: . Sample BH , Depthv ,(m); -, - . ~
Page 109: . , I , . . . . .. . , . , '," . ',
Page 112 and 113: Fig.7 Aeromagnetic anomaly map of t
Page 115 and 116:
\ Fig.13. Compilation map of resist
Page 117 and 118:
Q Q E C E CCt C E Ct C Q Ct CtQ C Q
Page 119 and 120:
!2 CO N A 4 ul o ~n o ul 0 DEPTH IN
Page 121 and 122:
Fig.25 BOREHOLE 5 C C C C Ct C E K
Page 123 and 124:
Fig.27 BOREHOLE 7 E Q C Q E C 0 Q E
Page 125:
81 82 83 84 Fig.30. : Location of c
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Exploration for porphyry-style copper mineralisation near Llandeloy

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