Table 1.

Quantitative biomarker data for granite-hosted bitumen and rocks sampled for comparison

Sample descriptionD/SC29 20S/(S + R)C32 22S/(S + R)Ts/TmPr/PhPr/nC17Ph/nC18C27 (%)C28 (%)C29 (%)
South Crofty ABitumen on planar brittle fracture0.170.160.580.440.420.452.22282844
South Crofty BBitumen on irregular fracture with alteration minerals0.210.380.480.340.541.191.15322840
South Crofty HBitumen on irregular fracture with alteration minerals0.450.470.780.570.840.610.68402040
South Crofty NHMPure bitumen, no context0.250.520.370.510.250.921.25472825
South Crofty YBitumen on irregular fracture with alteration minerals0.350.370.650.620.951.930.99303040
North TreskerbyBitumen on planar facture with sulphides0.660.310.520.650.620.530.68283042
Wheal SpeedSooty bitumen from quartz vein0.550.490.560.550.890.570.92502426
Mupe Bay JurassicBitumen-rich clast in sandstone0.740.380.680.63NDNDND352540
Quantocks DevonianBlack limestone1.590.420.670.390.550.100.20601822
Blue Anchor TriassicBlack shale0.130.450.610.422.411.210.68311356
Bovey Tracey OligoceneLigniteND0.15NDNDNDNDND9685

ND, no data; Pr/Ph, pristane/phytane; C29 20S, C29 20S/(20S + 20R); D/S, C29 βαR diasterane/αββR sterane; C32 22S/(22S + 22R); Ts, C27 18α-22,29,30-trisnorneohopane; Tm, C27 17α-22,29,30-trisnorhopane.