Lying on die transitional bell between the Sichuan Basin and the Qinghai-Tibet Plateau. Jinzhaigou belongs to the Songpan-Ganzi geocynclinal area, right on the front segment of China 's secondary topography. On the strongest fault line of landform transformation, Jinzhaigou descends from its high south to the low north, with a variety of kind features including mountains, valleys, lakes, waterfalls, streams and intermontane belts - a typical landform of alpine valleys. Mountain ridges average in altitude between 3.500 to 4,500 meters, the highest is the Ge'erna Peak ( 4.764m ) and the lowest Yangtong ( 2,000m ). The entire Place of Scenic Interest features crisscrossing valleys and overlapping mountains, like a nature's resplendent epic that has recorded vicissitudes of the crust transformation and progress of the earth's evolution.
Legend has it that Jiuzhaigou is a fairy's incarnation, and her story arouses endless imaginations. In a scien- tific point of view, Jiuzhaigou is shaped on overlap- ping waterfalls of Cui Hai (the Jade Lake), and evolves to its current looks on the ground of crust transformation, glacial movement, karst landform and travertine accretion.
Crust Transformation
As Far back as the Paleozoic of some 400 million years ago, Jiuzhaigou was under the seawater. Due 10 the Himalayas orogenesis from the Quaternary Pleistocene period, the crust experienced drastic transformation, and mountains rose irregularly. Under the force of glaciers and water erosion, high peaks and (loop valleys came into being. Furthermore, earthquakes contributed to cliff collapses, sliding, mudflow accumulation, lime corrosion, and travertine accumulation resulted in deep- valley lakes and pouring waterfalls. It is believed that the current landform and landscape scenery of Jiuzhaigou took shape at some 2 to 3 million years ago.
Glacial Movement
From the Quaternary lo late Pleistocene, the altitude of many Jiuzhaigou mountains was as high as over 4, 000 meters, close to the snowline. As the glacial cli-mate approached, glacial action took place in alpine areas, and glaciers extending down lo 2,800m valleys, leaving behind terminal and side moraines, dike barriers which blocked the water and helped to shape lakes. The Long Lake is a barrier lake formed in the Quaternary glacial period. Even today in Jiuzhaigou, visitors may find traces of the Quaternary glacial ruins, particularly glacial cirques and ice gorges, as well as hanging and trough valleys.
Karst Landform
The karst landform is a precondition for existence of hanging cliffs and waterfalls. On a lifted fault platform, the accumulated mudflow deposits were under die karst action and turned into travertine accretion, which con- tribute to the height of its waterfalls, typically the grand sight of the Nuorilang Waterfall, On it's 30-m wall, water pours down in an overwhelming manner. The well-developed glacial and karst landforms lay a foundation for the natural scenery of Jiuzhaigou.
Travertine Accretion
Travertine refers to sediments mainly made of calcium carbonate substance. The unique features of Jiuzhaigou travertine sites are the product of water How and bio-karst interaction, while depositing of travertine sediments becomes dike barriers on the lakebed. As years proceed, travertine layers pile up and form different- sized travertine lake banks along down streams. The water spots blocked out become the lake cluster in a staircase shape. Water overflows one stair after another, and forms both high waterfalls and low overfalls. Furthermore, aquatic plants, mosses and algae help to create colorful lake sights, the very core of Jiuzhaigou's unique natural beauty.
