Varkala Cliff Section

The cliffs at Varkala are a wall of red and buff rock rising straight out of the beach, running for a few kilometres along the Kerala shore. On a coast that is otherwise low, sandy and flat, they are the only real cliffs, which is what makes them worth a second look.

What they expose is a stack of nearly flat-lying sands and clays, capped by a hard reddish crust. Geologists call these layers the Warkalli Formation, and Varkala is the type area, the place the rocks are named after and measured against. It is one of the very few spots on India’s west coast where this whole sequence is cut open and visible instead of buried underground.

The sediments themselves are old shoreline. They were laid down in the Miocene and Pliocene, very roughly 20 to 5 million years ago, when this stretch sat at the edge of the sea and rivers and waves spread out sheets of sand, mud and buried plant matter. That plant matter, squeezed and darkened over time, survives in the cliff as seams of lignite, a soft brown coal, along with the pale clays and sands stacked above it. In a few places near Pozhikkara the cliff also cuts down into the older Quilon Formation beneath, a marine limestone, so two chapters of the coast’s history sit one on top of the other.

The red cap on top is laterite. In a hot, wet climate like Kerala’s, rain slowly leaches most of the soluble minerals out of the ground and leaves behind iron and aluminium oxides, which bake into a tough, rusty crust. At Varkala that weathering reaches down some 10 to 13 metres into the sediments, which is why so much of the exposed rock is stained red rather than showing its original sandy colour.

None of this would be visible if the land had simply stayed put. The whole block here was pushed up, by roughly 25 metres, along the West Coast Fault, the long line of crustal breakage that gives peninsular India its unusually straight western edge. Once the soft sediments were lifted above the water, the Arabian Sea went to work on them, and the surf cut back into the raised ground and carved the vertical face we see now. Elsewhere along this coast the same rocks lie hidden below the beach; here, uplift raised them and the sea exposed them.

That combination is why Varkala is protected as a National Geological Monument. The cliff is a rare open book of the west coast’s Neogene past: the shoreline sands and clays at the bottom, the plant beds turned to lignite, the marine limestone below, and the laterite crust on top. It even carries jarosite, an iron-sulphate mineral that also turns up on Mars, so the same face is studied as an Earthly stand-in for Martian ground. The cliffs are the way they are because the land rose and the sea cut in, turning buried history into something you can walk up to and read.

A short reference note: this summary draws on third-party sources such as the Geological Survey of India and Wikipedia. In time I plan to give every geological feature its own learning-oriented write-up — with custom diagrams, graphs, and study pointers — as I’ve already done for the 11 locations that have an Instagram reel.

Sources