In the summer of 2008, I trekked the Sichuan province of China. One of the destinations was the Huang Long Nature Reserve.

Huanglong Nature Reserve is a 3.6 km long valley which is tucked away deep in the Sichuan Province, among thick, primeval forests, and descends from 3,578 m to 3,145 m above sea level. The valley is a World Heritage Site, lying about 3,000 km north of Chengdu, the capital of Sichuan.

The Huang Long Nature-Reserve valley is covered with a thick, yellowish layer of carbonate of lime, which forms around differently shaped and sized ponds that join together like a terraced field, (pictured below).

Huang Long comprises about 3,400 colored ponds. The algae and bacteria in the ponds cause the mineral-rich waters to glow in hues of creamy white, silvery gray, amber, pink, and blue, (a process that is particularly striking when the weather was good).

Viewed aerially, the limestone valley resembles a massive yellow dragon, and the glistening pools look like dragon scales. “Huang Long” in Mandarin-Chinese means “yellow dragon”.

There are many other karst features to be found here which are worth exploring, (i.e. the attractive caves and grottos coupled with the unusual travertine pools themselves). This makes the park a geological paradise.

The main tributaries of the Fujiang River flow through the Huang Long Nature-Reserve, and there are a number of hot springs located here. Two of the most important springs are in the Mouri Gully, (Kuang-quan and Feicui), and both are said to have healing properties due to their high mineral content.

Huang Long is situated at the interaction of four floral regions, (the sub-tropical and tropical zones of the northern hemisphere; Eastern Asia, and the Himalayas). This means that the plant-life is very diverse and it supports 1500 species of plants.

Many endangered animals can also be found at the Huang Long Nature-Reserve, including the golden snub-nosed monkey, Asiatic black bear, Szechwan takin, common goral, and the giant panda.

The Huanglong Valley is located in the Minshan Mountains. The Minshan Mountains are very rich with this limestone and the wonder of Huang Long has formed from dissolved Carboniferous and Permian limestone. At the height of 3650 m in the valley are located the powerful Zhuanhuachi Springs with a medium output of 96 liters per second of water. In theory this is thermal water, because it is 5 degrees warmer than the surrounding atmospheric annual temperature. But… nevertheless, it is quite cold, only some 5° C “warm”. {Picture below}

Huang Long Springs

Pictured above, the spring water contains the dissolved carbonates and, as it reaches air, the chemical reactions with the oxygen leads to the precipitation of limestone rocks. Thus, step by step the bright white travertine is formed on the bed of the stream. But in many locations the living world interferes in geological processes where microscopic cyanobacteria and bryophytes bring in bright yellow, green and rusty colors.

Huang Long travertine formations are very long. In the 3.6 km of, the elevation drop is 530 m. Thus a walk from one side to another and then back is not that easy. The thickness of travertine formations varies from 9 to more than 20 meters.