Sands of Time - Sculpted by millennia, Chad is a place of ancient geology and epic grandeur. Aminatta Forna finds her place in it all

The 15,000-square-mile Ennedi Massif, in north-eastern Chad, is a plateau the size of Switzerland. Between 350 million and 500 million years ago, this part of the globe was an ocean. Then the ocean disappeared, leaving the sandstone floor exposed. The climate shifted from rain-soaked to arid. Sun, wind, and water sculpted the sandstone into a dramatic, desolate, unearthly landscape of gorges and valleys, inselbergs and stacks, towering tassili and natural arches. In the desert the delicate threads of life become apparent in trails of tiny footprints scattered across the sands: here, the tear-shaped tracks of a lizard; there, the dimpled prints of a gerbil.

- By Aminatta Forna - Photographs by Alistar Taylor-Young

From a distance, the sandstone pillars resembled a gathering of giants turned to stone by a displeased god. Our group of eight travelers had set out when the sun was at its zenith, and now, as it made its descent, we arrived at this place with air so pure it seemed to hold no scent. The only sound was the wind, as faint as breath. The rocks are called tassili, and some stand more than 300 feet high. They have been carved by this same disarmingly gentle wind over many thousands of years. This is what deep time feels like.

When I was a child, a teacher tried to give my class some sense of eternity. Imagine a rock 10,000 miles by 10,000 miles. Every 10,000 years a small bird comes and wipes its beak this way and that upon the rock. Deep time, Earth time, captures the entire process of erosion, until the rock is finally worn away.

Youths gather at the base of Aloba Arch, the world’s second-tallest natural arch.

The 15,000-square-mile Ennedi Massif, in north-eastern Chad, is a plateau the size of Switzerland. Between 350 million and 500 million years ago, this part of the globe was an ocean. Then the ocean disappeared, leaving the sandstone floor exposed. The climate shifted from rain-soaked to arid. Sun, wind, and water sculpted the sandstone into a dramatic, desolate, unearthly landscape of gorges and valleys, inselbergs and stacks, towering tassili and natural arches. In the desert the delicate threads of life become apparent in trails of tiny footprints scattered across the sands: here, the tear-shaped tracks of a lizard; there, the dimpled prints of a gerbil.