Abstract
Oil residues in Variscan granites in Cornwall, SW England, preserve biomarker data which indicate an origin from marine source rocks. The biomarkers also indicate a thermal maturity that excludes an origin from the Devono-Carboniferous rocks intruded by the granites, but is similar to that of Jurassic-sourced oil to the east in the Wessex Basin. A suite of five different samples from the South Crofty tin mine are variably biodegraded, implying alteration after emplacement of oil in the granite. These characteristics are compatible with models for updip flow of fluids from offshore Mesozoic sediments into older granite topographical highs.
Highlights
Oil residues in Variscan granites in Cornwall, SW England, preserve biomarker data which indicate an origin from marine source rocks
Five of the seven samples are from South Crofty Mine in the Carnmenellis Granite (Fig. 1; Table 1) but collected at different times, allowing the measurement of a set of samples with variable degrees of alteration
Harrison and the collections of the Natural History Museum, respectively
Summary
Oil residues in Variscan granites in Cornwall, SW England, preserve biomarker data which indicate an origin from marine source rocks. Mostly from the nineteenth century, record oil at many mines (commonly described as mineral pitch; literature reviewed by Parnell 1988). Despite this heritage of observation, and much detailed study of the metalliferous mineralization The present study presents organic biomarker data from seven samples of viscous/solid oil residue from mines in Cornwall. The objectives for these data are to:
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
