Based on their studies of Jiuzhaigou glacial cirques and U- shaped valley, geologists believe that the Lang Lake is a cirque glacier belt, one of other hanging and Hal-topped glaciers in Jiuzhaigou. Some tens of thousands of yean ago. the glacial scenery was especially charming and spectacular. The ice flows wore running down through the foot of Snow-clad mountains and among valleys. Glaciers appeared and disappeared on and off, ice sticks towered up into the sky. ice holes looked like a crystal palace, and ice drops resembled a treasured collection of jewelry - all were contributing to the incredibly fantasy of Jiuzhaigou's natural beauty.
Riddle-How could the water sites of Jiuzhaigou be so colorful? As we know, the color of water Is determined by a number of factors: water dispersion, water-surface reflection, the reflex of the lakebed substances, as well as the comprehensive effect of visual stimuli. As the sky of Jiuzhaigou Is oftentimes clear and clean, strong short-wave radiation contributes to the rayleigh dispersion. Meanwhile, as the water selectively absorbs and disperses the sunlight, it gives off short light waves, thus appears purplish blue, In deep lakes, the water appears dark blue due to its dispersing light; in shallower lakes, colorful algae makes the water color more changeable. For instance, the light yellow and yellow-brown algae in the Wuhua (Five Flower) Lake Is able to selectively absorb sunlight so as to give off red and green lights. In the course of its reflection, the red light becomes lighter and dimmer. Therefore. the water appears greener as the lake Is deeper. Besides, the dispersed blue color joins this process, and all these factors become of the grounds for the colorful lake water. Furthermore, weeds and algae grow in patches on the lakebed. the spot without weeds and algae appears blue, resulting in irregular shapes. The decayed logs, lakeside inverted reflections and rip- pling lake surfaces help to enrich the color changes into yellow, yellowish green, peak green, green, greenish blue and blue.
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.
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.
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.
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 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.