Exploration for porphyry-style copper mineralisation near Llandeloy

More documents

Recommendations

Info

-1 00- Contours of VLF horizontal intensity. 2% intewals Apparent resistivity >2000 ohm metres Apparent resisitivity 1000-2000 ohm I-etres Apparent resistivity 500-1 000 ohm metrss Figure 17 VLF-EM and apparent resistivity map of the Middle Rlill area 18
and geophysical anomalies were identified. Explanations for them were not evident from the examination of surface exposures and nine boreholes were drilled to find their causes. In addition, a gravity survey was carried out in an attempt to find another method for refining the setting of the mineralised zone. Down-hole geophysical measurements were taken in five of the boreholes. All the boreholes were drilled using the B.G.S.JKS 300 rig. Eight vertical holes were drilled to between 21.45 and 45.72 m; the ninth, an inclined hole, was stopped at 124.12 m. BQ core was retrieved from all holes above the depth of 72.26 m; and AQ below that in the ninth hole. In boreholes 1 and 8 no samples were collected until the first solid core was retrieved. In all the other holes samples of the superficial deposits were taken while the casing was being driven. While drilling it was discovered that much of the area was underlain by a previously unrecorded, locally thick succession of superficial deposits. The third borehole (3A) was stopped at 26.83 m and re-sited in an attempt to avoid this deposit, but on the second attempt this borehole (3B) penetrated the same thick deposit and collapsed before solid was reached. Detailed logs of all nine holes have been lodged with the Aberystwyth office of B.G.S. Abbreviated logs are presented in Appendix 1 and graphic logs in Figs. 20 to 28. Introduction The map showing the solid geology for the area around Tref fynnon (Fig. 18) was constructed using data from the few outcrops still accessible, the map of H. H. Thomas, the geophysical surveys, the boreholes and the distribution of float, Measurements of the dip and strike Figure 18 The solid geology of the area around the boreholes of stratified rocks were possible at only two localities and the exposures were such that modification of the orientation by hillcreep or other agencies could not be ruled out. Information on the superficial deposits was gained mainly by hand augering during the soil survey, and from the boreholes. Table 7 The stratigraphic succession in the Treffynnon area Sedimentary and volcanic rocks F Igneous rmks In this section account is taken only of the small area of the detailed survey carried out around Treffynnon. Notes on the whole of the reconnaissance area are in the regional account. The succession (Table 7) consists of sedimentary and volcanic rooks of possible Cambrian and Ordovician age into part of which is emplaced a complex of intermediate and acid intrusive rocks. Lacustrine sediments of probable Tertiary age occur in much of the - Road , , - , Geological boundary , , Fault 19 Drift deposits Lacustrine deposits Tetragrap tus Shales Brunel Beds TreffynnonGroup volcanic rocks Solva Group quartz- wacke wd siltstone Intermediate and acid intrusions Pleistocene ?Ter tiary Ordovician ?Cambro/(Xdovician C.mbrian Post-Cambrian Tetngraptua Shales Tmffynnon Group 7'
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 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 64 and 65: APPENDIX 1 ABBREWATEI) BOREHOLB LOG
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
show all

Exploration for porphyry-style copper mineralisation near Llandeloy

Create successful ePaper yourself

Delete template?

Save as template?