Effect of volcanic activity on level of organic maturation in Carboniferous rocks of East Fife, Midland Valley of Scotland

Abstract

Maturation levels, determined by reflectance measurements, of primary vitrinite in Lower Carboniferous sediments, are compared with those of vitrinite-bearing clasts enclosed in closely associated tuffs of volcanic necks that resulted from Surtseyan-type activity of probable Stephanian age. Preliminary data show wide variation of reflectance in the tuffs and a pronounced contrast between the reflectances of the vitrinites in the sediments and the tuffs, suggesting that development of maturation in the two rock types was unrelated. the maturation level of these Lower Carboniferous sediments in this eastern part of the Midland Valley (threshold of the 'oil window' at Rrmoil(average) ≈ 0.55%), contrasts with a substantially higher degree of maturation for equivalent horizons in the central Midland Valley (Rrmoil(average) ≈ 1.30%: 'gas-generating' maximum). © 1988.