Well Number Sample depth Oil sample characteristics Tectono-strat unit (seeRichards and Hillier, 2000)
14/5-1A 1728 m Biodegraded, but of mature character. Corresponding Type II source rock contained predominantly structureless organic matter; similar to that in a side-wall core sample analysed from 2677m below rig floor (within the uppermost parts of  the late syn-rift sequence). Middle post-rift
14/5-1A 1948 m Biomarkers exhibit a high degree of maturity, and show the oil is derived from the early post-rift, Type I source rock Early post-rift
14/5-1A 1950 m The sample is immature as indicated by presence of the thermally unstable compound C27-22,29,30-trisnor-17b(H)-hopane, the concentration of which reaches zero at the earliest oil window. The differences between this and the sample from 1948 m may be due to the fact that part of the organic matter in this interval represents indigenous, immature material, whereas another part is derived from migration of low mature material. Early post-rift
14/10-1 ?3000 m Oil (API 27.1) was collected at surface during terminal logging. The complete sterane isomerisation observed indicates that this oil has been expelled from a mature source rock. This source rock contained structureless organic matter with a significant algal component, and is equivalent to the Type I lacustrine claystones found in the the early post-rift source rock interval in Well 14/5-1A. However, the source rock interval from which this recovered oil was derived was apparently more mature than the early post-rift source rocks analysed from well 14/5-1A. Late syn-rift
14/9-1 1830 m Oil was centrifugally spun from a core sample. This oil has an early mature, highly paraffinic composition, and has been derived from a Type I lacustrine source rock. The oil is carbon isotope depleted, and is similar in nature to the Valanginian to Barremian source rocks comprising the lowermost part of the early post-rift succession recorded in Well 14/5-1A. The oil is also isotopically similar to the oil recovered at surface in Well 14/10-1. Middle post-rift
14/24-1 1790 m Post-well geochemical analyses indicate that a sandstone from near the base of the middle post-rift sequence contained traces of hydrocarbons that were not detected during drilling, presumably due to their very low concentration (although dull gold to yellow fluorescence was noted while drilling through the underlying source rocks). These hydrocarbons are characterised by normal alkanes with a mature configuration, and do not resemble the indigenous hydrocarbons detected in the immediately underlying claystones. They probably represent migrated hydrocarbons originating from a deeper, mature zone of the underlying Type I claystones.

Onshore Geology Images

geology mapgeology map

Fig.2: Gondowanaland reconstructionFig.2: Gondowanaland reconstruction

Fig.3: Comparison of Falklands and South African stratigraphyFig.3: Comparison of Falklands and South African stratigraphy

Fig.4: Onshore vertical successionsFig.4: Onshore vertical successions

Fig.5: Cross-bedding in the Devonian rocksFig.5: Cross-bedding in the Devonian rocks

Fig.6: Fossils from the Devonian Fox Bay formationFig.6: Fossils from the Devonian Fox Bay formation

Fig.7: Fitzroy Tillite formationFig.7: Fitzroy Tillite formation

Fig.8: Gold ocurrence in streamsFig.8: Gold ocurrence in streams

Fig.9: Charles Darwin's fossils (Courtesy of the Natural History Museum, London)Fig.9: Charles Darwin's fossils (Courtesy of the Natural History Museum, London)

Fig.10: Archaeocyatha fossils Fig.10: Archaeocyatha fossils

Fig.11: Fossilized fish trailsFig.11: Fossilized fish trails

Fig.12: Life in the Devonian seas (Copyright: Richard Cockwell)Fig.12: Life in the Devonian seas (Copyright: Richard Cockwell)

Fig.13: Craggy Falklands SceneryFig.13: Craggy Falklands Scenery

Fig.14: Mount Kent stone runFig.14: Mount Kent stone run

Fig.15: Mount Wickham Stone RunFig.15: Mount Challenger Stone Run