A Dune Disguised as Stone: How Soft Sand Became the Walls that Stopped Napoleon (And Why It’s Crumbling Before Our Eyes)

Nir Topper
5 minutes ago
3 min read

The Kurkar ridges (Aeolianite, Calcareous sandstone), the backbone of the Israeli Coastal Plain, are actually geological "newcomers." It all begins in Ethiopia and Sudan: granite and basalt rocks erode, carried by the mighty Nile River to the Mediterranean Sea. From there, sea currents transport the quartz grains (sand) north to our shores. But the real magic happens here: in a process of "lithification" (turning into stone), rainwater dissolves tiny shell fragments within the dune, transforming them into a natural cement that binds the grains together. Thus, a soft dune becomes hard rock. The Kurkar ridges are, in essence, fossilized dunes—a silent testimony to much rainier periods in our land's distant past.

However, the story doesn't end at the current coastline. Submerged Kurkar ridges lie hidden underwater off the coasts of Atlit and Haifa. This is fascinating evidence of the Last Glacial Maximum, approximately 20,000 years ago. At that time, global sea levels were about 130 meters lower than they are today, and the coastline of the Land of Israel extended far to the west. These underwater ridges tell us of a vanished ancient world, an era when early humans walked where fish and submarines swim today. The Kurkar serves as a climatic archive, built of layers—a "sandwich" of Kurkar and Hamra soil—that teach us about extreme fluctuations between aridity and humidity throughout history.

Beyond geology, the Kurkar ridges dramatically dictated our settlement map and history. The longitudinal ridges (the western, central, and eastern) acted as natural dams, blocking the flow of streams from the mountains to the sea. The result was the formation of vast swamps behind the ridges, such as the Kabara swamps and the "Bassa" in Herzliya. To survive and cultivate the land, the Romans and Byzantines were forced to execute immense engineering projects: they hewed tunnels and breached the hard Kurkar rock (as seen at Jisr az-Zarqa and the Poleg Stream) to drain the water. This struggle between humanity and geology shaped the landscapes of the Sharon and the coast as we know them today.

Kurkar is also the material from which our architectural history was built. Lacking hard limestone on the Coastal Plain, ancient builders utilized the available Kurkar to construct magnificent cities. Herod built Caesarea—with its theater, palace, and aqueduct—from this local stone. The Crusaders fortified Acre and Apollonia with mighty Kurkar walls. Later, it was Ahmed al-Jazzar who erected massive Kurkar walls in Acre, the very same famous fortifications that Napoleon Bonaparte besieged but failed to breach. Although it is a stone that is easy to quarry and provides thermal insulation, it is highly sensitive to salt and sea spray ("salt weathering"). Today, we are witnessing complex conservation efforts using advanced technologies to save these monuments, after modern cement renovations in the past caused them more harm than good.

Finally, the Kurkar ridges are "islands" of unique nature in the heart of Israel's most densely populated region. They serve as a rare habitat for endemic plants—those that grow nowhere else on earth—such as the Coastal Iris (Iris atropurpurea), Rothschild's Sorrel (Rumex rothschildianus), and Centaurea procurrens. These ridges are the last remnant of a primal landscape, a vital ecological corridor, and a reminder of the fragility of the retreating coastal cliff. When we hike along the cliffs at Ga'ash or Netanya, we are walking on fascinating geological and human history that is our duty to know and preserve.

Did you enjoy this? Like and share! Know of any other hidden Kurkar spots? Let me know in the comments.

#Kurkar #Geology #Israel #History #IsraeliNature #Science #NatureConservation