Because the lake is in the west of Hang Cheng, it is named West Lake. The earliest name of "West Lake" appeared in Bai Juyi's two poems. The West Lake returned to Gushan Temple in the evening to present guests, and Hangzhou returned to the boat. After the Northern Song Dynasty, most famous poems were named after the West Lake, and the name of Qiantang Lake was gradually unknown. Su Shi's Seeking the West Lake in Hangzhou is the first time to use the name "West Lake" in official documents.
Extended information West Lake was originally called Wulin Water. Ban Gu's History of Han Geography in the Eastern Han Dynasty records: "Qiantang governs the West. Wulin Mountain, where Wulin water comes, goes east into the sea and travels 800 miles. " It is generally believed that Wulin Mountain is the general name of the mountains around Lingyin and Tianzhu. Nanxi and Beixi, which originated here, flow into Jinsha River and flow eastward into West Lake, which is the largest natural water source of the West Lake.
So the name "Wulin Water" is the earliest recorded name of West Lake. Later, there were various names such as Qianshui Lake, Qiantang Lake, Ming Sheng Lake, Jinniu Lake, Hanshi Lake, Shang Hu Lake, Kongtong Lake, Fangchi Lake, Xizi Lake, Gaotu Lake, Xiling Lake, Longchuan Lake, Xiaojinguo Lake, Ren Mei Lake, Xianzhe Lake and Yueming Lake, but only two were generally recognized and documented in the past dynasties. First, because the lake is west of Hang Cheng, it is named West Lake. ?
Li Daoyuan's Notes on Water Classics in the Northern Wei Dynasty recorded: "There is a sacred lake in the Ming Dynasty near the Nanjiang River in the county. According to the legend of elders, there are Taurus in the lake. Seeing it in ancient times, it is unpredictable, and the lake is named. " At this time, two other ancient names of West Lake were derived: Ming Sheng Lake and Jinniu Lake. ?
The earliest name of "West Lake" appeared in Bai Juyi's two poems. The West Lake returned to Gushan Temple in the evening to present guests, and Hangzhou returned to the boat. After the Northern Song Dynasty, most famous poems were named after the West Lake, and the name of Qiantang Lake was gradually unknown. Su Shi's Seeking the West Lake in Hangzhou is the first time to use the name "West Lake" in official documents. ?
The reasons for the formation of the West Lake are briefly recorded in ancient books. In the Ming Dynasty, a volume of "Journey to the West Lake" was published: "The West Lake is surrounded by mountains on three sides, streams and valleys, and there are hundreds of deep springs under it, which is a lake." Modern scholars have made textual research on topography, geology, sedimentation and hydrodynamics, among which the general view is that the West Lake is a lagoon gradually evolved from a bay. ?
Lagoon (formerly called lagoon) is a local seawater body separated from the open sea by sand mouths, sand bars or corals in the coastal zone. The lateral movement of coastal sediments can often form a combination of offshore dams and lagoons. When the waves move to the shore, sediments accumulate parallel to the coast, forming an offshore dam with high water surface. The dam divides the seawater and forms a semi-closed or closed lagoon inside.
Under the action of tidal current, dams can be washed away, forming tidal channels. The sediments brought into the lagoon by the high tide form a tidal delta at the estuary. Lagoon sediments are filled with river, coastal sediments and tidal delta materials, mainly composed of silt, silt and gravel, and usually contain black organic clay and shell debris. ?
1920, scientist Zhu Kezhen published "The Reasons for the Formation of West Lake in Hangzhou" after investigating the topography of the West Lake, which said: "The West Lake was originally a small bay on the left side of Qiantang River, but later, due to the siltation of Qiantang River, the mouth of the bay was slowly blocked and turned into a lagoon."
Zhu Kezhen also inferred from the sedimentation rate that the West Lake began to form before 12000. Zhu believes that the area at the beginning of the formation of the West Lake was larger than it is now. Later, due to the injection of three mountain streams, sediment gradually filled the West Lake, and the lake gradually narrowed. The West Lake would have been abandoned long ago if it hadn't been dredged continuously through the ages.
1924, geologist Zhang published "The Solution to the Genesis of the West Lake in Hangzhou", which supplemented Zhu's view that the formation of the West Lake began in tidal force, piled up into a lake embankment, and then maintained the lake surface with the change of beaches, which were two important conditions for the formation of the West Lake. ?
However, Hu Fei's theory has been questioned in modern scientific research. 1950, the geological department sampled and analyzed the geological boreholes in West Lake Island and lakeside park. It is believed that a strong volcanic eruption occurred in the area of present-day lakeside park in the Late Jurassic of One Happy and Fifth millions of years ago, and a large number of volcanic rocks accumulated at the bottom of the Baoshan Mountain and the West Lake (mostly). As a result, the crater once fell, causing low-lying water in the horseshoe-shaped core, which is the embryonic form of the West Lake.
From 65438 to 0979, geologists analyzed microfossils of rock samples taken from boreholes near the lake. According to the combination of different fossils, the formation process of the West Lake can be divided into three stages: early lagoon, middle lagoon and late lagoon. The sandbar accumulation formed by the surge of Qiantang River finally formed today's West Lake pattern. ?
From August 16 to August 18 of the lunar calendar, the sun, the moon and the earth are almost in a straight line, so the sea water is most attracted by the southeast wind on this day, and the wind direction is generally consistent with the tide direction, which encourages the tide and is influenced by the bell mouth of Qiantang River.
Nearly 500,000 mu of land was reclaimed to the east of Zheshan Mountain on the south bank of Qiantang River, which blocked the estuary like a peninsula, making the section from Zheshan Mountain to Qiantang River 12 like a small belly bottle, which is easy to retreat when the tide rises. The width of the outer mouth of Hangzhou Bay is 100 km, which is only a few kilometers away from the outer 12 section. The riverbed in the eastern part of the estuary suddenly rises and the beach is shallow. When a large number of tides flood in from the mouth of Qiantang River, it is difficult for the river to retreat because of the rapid contraction of the river surface.
Secondly, it is related to the sediment deposition under the Qiantang River. These sediment deposits play a role in blocking and rubbing the tidal current, making the front slope of the tidal current steep and gentle, thus forming the back wave to catch up with the front wave, and the descending sediment also accumulates in this area, raising the Qiantang River bed, and finally the West Lake is completely closed, and the water body gradually desalinates, forming the current West Lake. ?
The mountains around the West Lake belong to the remnant veins of Tianmu Mountain. According to different lithology and mountain height, it can be divided into two types: inner ring and outer ring. Beifeng, tianmashan, Tianzhu Mountain, Wuyun Mountain, etc. They are all in the outer circle and belong to high hilly terrain. The mountain is mainly composed of Silurian, Devonian lithic sandstone and timely sandstone, with hard lithology and not easy to be weathered and eroded.
Beautiful peaks, vertical and horizontal streams and clear running water are the areas with the most springs in the West Lake. There are Feilai Peak, Nanfeng, Huang Yu, Fenghuang Mountain and Wushan Mountain in the inner circle, with low mountains and rolling hills. The mountains are all syncline mountains, mainly composed of Carboniferous and Permian limestone, which are easily eroded by water flow, forming Xia Yan, Leshui, Shiwu, Zilai and Ziyun caves. In addition to karst hills, there are also Geling Mountain and Baoshi Mountain, which span the northern edge of the West Lake and are composed of pyroclastic rocks, with an altitude of 100 meters. Gemstone Mountain has a magnificent landscape, steep and spectacular stone gorge, secluded cliffs and ochre gems (jasper) embedded in the rocks.
Reference: Baidu Encyclopedia-West Lake