Coarse-sediment bands on the inner shelf of southern Monterey Bay, California

Bands of coarse sand that trend parallel to the shore, unlike the approximately shore-normal bands found in many inner shelf areas, occur in southern Monterey Bay at water depths of 10–20 m, less than 1 km from the shore. The bands are 20–100 m wide and alternate with bands of fine sand that are of similar width. The coarse-sand bands are as much as 1 m lower than the adjacent fine-sand bands, which have margins inclined at angles of about 20°. The mean grain sizes of the coarse and fine sand are in the range of 0.354–1.0 mm and 0.125–0.354 mm, respectively. Wave ripples that average about 1 m in spacing always occur in the coarse-sand bands.