Sibebe Rock

Sibebe is a huge granite mountain in Eswatini, about 10 kilometres from the capital city, Mbabane. It rises 350 metres above the valley of the Mbuluzi River, and its smooth, bare top gives it the nickname Bald Rock. Wikipedia calls it the second-largest monolith in the world, which means a giant single block of stone.

It is also described as the largest exposed granite pluton. A pluton is a mass of rock that cooled slowly from molten rock deep underground and was later uncovered when the soil above wore away. The card says the granite formed around 3 billion years ago. Sibebe is a favourite place for walkers, and every year several thousand people join a charity climb called the Sibebe Survivor.

What is a granite pluton?

Long ago, melted rock pushed up into the crust and cooled slowly, trapped below the surface. Slow cooling lets large crystals grow, and the result is granite. Over millions of years, wind and water stripped away the softer rock around it, until the hard granite dome was left standing above the valley. Sibebe is an example of this: a mass of stone made underground that is now a mountain in the open air.

Climbing and walking

Because the rock is smooth and bare, walkers can climb across its broad slopes and enjoy wide views of the valley. The Mbabane-Mbuluzi Rotary Club organises an annual fund-raising walk up the rock called the Sibebe Survivor, and several thousand people take part each year. The mountain has even given its name to a local lager, Sibebe Premium Lager.

On the globe

The model shows a great smooth granite dome rising above the valley near Mbabane.