Comparison of namurian sediments of the central pennines, England, and recent deltaic deposits

Abstract

This paper makes a general comparison of sediments of the Namurian delta in the central Pennines and sediments of Recent deltas. Some of the detailed evidence on which this comparison is based has been presented elsewhere and is only summarised here. As a result of the comparison it is concluded that the coarse sandstone of the Namurian deposits were laid down by rivers, and the sandstones of intermediate grain-size (0.3–0.1 mm median diameters) are tidal deposits. The marine shales of the Namurian, and their associated non-marine shales, resemble the deposits of tranquil embayments near modern deltas, and the laminated fine siltstones that usually succeed the marine shales closely resemble present-day pro-delta silts. The importance of compaction and of diachronism is stressed.