Karsts towers and topography

Guilin’s most renowned feature is its dramatic karst terrain. Rising sharply at odd angles, limestone peaks look like giant teeth growing out of the green plain…

This is how the landscape surrounding Yangshuo was described by Ray Beiersdorfer, a geologist at Youngstown State University in Ohio.

Beiersdorf’s description of Yangshuo’s landscape is both poetic and accurate. Yangshuo’s iconic geography has long been a draw for tourists and since it was  featured on the 20yuan note, the cover of China’s Lonely Planet, and in numerous documentaries and films about China,  including BBC’s series ‘Wild China’ the allure of Yangshuo’s unique landscape continues to pique the imaginations of people all across the globe.

The karst topography maybe unique, but it’s not unique to China. Formations similar to those in Yangshuo can be found in Vietnam’s Halong Bay, and a few places in the US, mainly Florida, and Virginia’s Shenandoah Valley. However, while each of these regions shares a similar topography the limestone karsts in Yangshuo are distinctive to China’s Guangxi Province. According to Beirsdorfer it was a combination of four conditions that occurred in Southern China and nowhere else, that are responsible for creating Yangshuo’s stunning topography. “First, you need hard, compact carbonate rock. In Guilin, it’s Devonian limestone. Secondly, you need strong uplift, in this case provided by the collision of India with Asia to form the Himalaya. Third, you need a Monsoon climate of high moisture during the warmest season. Finally, the area must not have been scoured by glaciers, which this region wasn’t.”

To simplify, the weathered limestone formations known as karsts were formed from fossilized prehistoric sea floor sediments. When the crashing of tectonic plates formed the Himalayas, the sea floor was pushed up exposing the alkaline limestone to the naturally-occurring acid rains of Yangshuo’s subtropical climate. As water on the surface seeped into the limestone, the dissolution of limestone caused caves and sink holes to form below the water table. As water continued to percolate into subterranean rivers, vast caverns and sinkholes were carved out causing the water tables to drop and the ground’s surface layer to sink. This in turn caused the formation of karst peaks. The process continued until the limestone layer within the subterranean caverns eroded away, exposing a layer of sedimentary shale. The end result is the Yangshuo which can be seen today, a topography consisting of karst mountains and small waterless caves.

There are predominating two types of karsts in Yangshuo, the isolated karst, known as fenglin or peak forest karsts, and the linked-base karsts, also known as the fengcong or peak cluster karsts. Fenglin karsts tend to rise vertically, 30 to 80m above the surrounding floodplains. Great examples of these dramatic tower-like karsts can be found in and around the city of Guilin.

Fengcong karsts tend to be more cone-shaped with karsts blending nearly seamlessly across small depressions or dolines. Xingping, a small village just outside of Yangshuo, is known for its beautiful fengcong landscapes.
Yangshuo’s karst landscape is awe inspiring and experiencing its beauty is without a doubt a must do for anyone visiting China.  As Beirsdorfer said, “China in general and the Guilin area specifically boasts some of the most spectacular karst topography in the world.”

For more information see:
www.irck.edu....
www.geotimes....
www.tourguizhou....