I inch my way down the narrow crevice, crouching to avoid the jagged edges of the limestone ceiling that hangs low over my head. In the inky darkness I have descended into, I peer around trying to discern some detail on the walls around me. I turn my head gingerly, and my head-torch lights up a spray of shimmering gold on powder white columns. I catch my breath as the ceiling gleams above me.
We are in one of Meghalaya’s smaller limestone caves, part of the subterranean world that lies underneath the region’s legendary green valleys and azure rivers. I am with wildlife photographer Dhritiman Mukherjee and a team of filmmakers on an exploration of the cave systems of Meghalaya, and the life they hold. While the caves occurring across the Garo, Khasi and Jaintia hills are typically limestone caves, Meghalaya also has sandstone caves like the spectacular, 24.5 kilometre Krem Puri, currently the world’s longest known sandstone cave. Our expedition, primarily in the East Jaintia Hills, involves exploring caves like Krem Chympe, Krem Umladaw and other unnamed, previously unexplored caves in the region. This cave is the first in a series we are exploring, a lesser-known, unnamed cave near Lumsnang in the East Jaintia Hills. Less than an hour ago, we trekked down a narrow, slippery path through dense bamboo thickets to reach a rocky overhang of limestone with a narrow opening at the bottom. Barely larger than a slit, I would have to curl myself up into a ball to enter, almost like a porcupine. In fact, it was a porcupine that had first led our local guide to this outcrop leading to the discovery of this particular krem, or cave in Khasi.
After a deep breath and contortion tricks that my gymnastics teacher from school would have been proud of, I crawl through the narrow entrance. Inside, it is another world.
The wealth of caves found in Meghalaya is unlike any other known karst (or limestone-dominated landscape) in India. What makes Meghalaya special is a combination of factors — a hilly plateau with elevations of over 1000m, a landscape rich in limestone, and an abundance of rainfall during the monsoon, among the highest recorded in the world. Fragile and mysterious, these subterranean habitats are formed by an extremely slow process of erosion by water — the wearing away of limestone or calcium carbonate bedrock over millions of years. Known as solution caves, these caverns typically form in sheets of solid limestone found below the surface like the caves that we explored near Lumsnang. In some cases, solution caves are also formed in other sedimentary rock strata that are soluble.
The process of cave formation is fascinating. When rainwater mixes with atmospheric carbon dioxide and other gases in the soil, it forms a weak acidic solution. Either in the form of underground rivers or as groundwater, this mildly acidic water dissolves calcite, the predominant mineral that occurs in limestone, to gradually carve out large cavities and often, complex cave systems.