From a satellite’s point of view, New Jersey’s barrier islands barely register, like fine white bones pulled from a body of green, separated by a vascular tissue of wetlands and shallow bays. Twenty thousand years ago, when the Laurentide ice sheet covered much of Canada and the northern United States, the coast of what would be New Jersey reached to the edge of the continental shelf, nearly 100 miles east of the present shoreline. For the next 10,000 years, as the last ice age came to an end and the sea level rose by more than 300 feet, the New Jersey coastline moved steadily west.

This alluvial coastal plain is stratified with quartz and glauconite sands, silt, clay and at least eight different aquifers going down beyond 6,000 feet before there is any semblance of solid earth — a slab of bedrock formed between 550 million and 300 million years ago. Geologists like to say that New Jersey’s coastal plain sits “unconformably” atop this Paleozoic base. Most unstable […]