A thick succession of Silurian conglomerates on Stord, showing clast-supported textures but no internal stratification, has been interpreted as resedimented. A distinct upwards change in composition from mainly sedimentary clasts to mainly igneous clasts, with upwards increasing grain size, suggests a shift in direction of drainage through time, with the latest phase of disposal from an uplifted igneous complex along the basin's northwest margin. The succession of conglomerates overlying tholeiitic basalts, graptolitic shales, and carbonates is interpreted in terms of an intercontinental rift basin sequence, marginal to a continent-based magmatic are. The conglomerates record the rifting, early sediment dispersal from the cratonic side of the basin, the later uplift of the magmatic are, and the gradual unroofing of its plutonic core.
Silurian conglomerate sedimentation and tectonics within the Fennoscandian continental margin, Sunnhordland, western Norway