A large area of Tulin landform, or earth forest, was recently found in Zhangye City, northwest China's Gansu Province, according to the city's National Geopark Administration.

Zhangye Tulin landform is mainly located in Sunan County, with an average elevation of 1,700 meters and an area of about 20 square kilometers. It is well developed and diverse in different varieties, from thin gullies and soil teeth in early stage, to round basin-shaped pillars in intermediate stage, and to residue pillars on a slope in mature stage.

The newly found earth forest, a product of water erosion and weathering, was formed around 100 million years ago from sediment composed of sand and mud in a river-lake environment, according to Cheng Jie, a professor at the China University of Geosciences. Its formation reflects the geological history of the Qilianshan mountain range in Gansu Province.