Karst Coast

A karst coast is a shoreline developed on soluble carbonate bedrock, mainly limestone and dolomite, where dissolution rather than mechanical wave action shapes the relief. Features include solution notches at the waterline, pinnacled limestone, sea caves, collapse dolines flooded as inlets, and drowned tower karst, as along the Adriatic Dalmatian coast and Ha Long Bay. The coastline often follows fracture-guided dissolution patterns, giving ragged, embayed outlines. Tidal mixing of fresh and salt water in the mixing zone sharpens dissolution at the waterline, cutting the characteristic notch. Karst coasts complicate survey and anchoring because of irregular submerged pinnacles.