The composition of 31 samples of Lower Cretaceous (Valanginian to Aptian) sandstone from ODP Sites 638 through 641 was analyzed using the Gazzi-Dickinson point-counting method. The results show that the source of the Valanginian to Hauterivian sand was a continental block, dominated by granitic and/or high-grade-metamorphic rocks. Although these petrologic results do not allow discrimination between various potential continental block provinces, they suggest, in conjunction with seismic profiles and regional considerations, that the source was the Galicia margin or western Iberia. In contrast, the Barremian and Aptian sand is dominated by carbonate grains that were derived from a carbonate platform, probably on Galicia Bank.

Supplement to: Johnson, Jeffrey A (1988): Composition of Lower Cretaceous sandstone, Galicia margin. In: Boillot, G; Winterer, EL; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 103, 505-512