Jiuhua Mountain

Jiuhua Mountain, known as Lingyang mountain and Jiuzi mountain in ancient times, is one of the "four famous Buddhist mountains in China". It is located in Qingyang County, Chizhou City, Anhui Province. It is known as "the first mountain in Southeast China". It is said that in Tang Dynasty, Li Bai's poem "looking at Jiuhua and presenting it to Qingyang Wei Zhongkan" said: "once upon a time, on the Jiujiang River, looking at Jiuhua peak. The green water in Tianhe River shows nine hibiscus. " It was renamed "Jiuhua Mountain".

Jiuhuashan Mountain is one of the three major mountain systems in southern Anhui Province, and its main body is a strong fault uplift belt composed of granite. The marginal area is mainly a slightly uplifted fold fault block belt composed of granodiorite, except for some sedimentary rocks. Jiuhua Mountain is located in the north subtropical zone, which is not only affected by the humid monsoon, but also restricted by the altitude and terrain of the mountain area, so it has the characteristics of mild, humid and cool mountain climate.

Jiuhua mountain lies on the Yangtze River in the north, Huangshan in the south, Taiping Lake in the East and Chizhou in the West. It stretches for more than 100 kilometers. There are mainly 99 peaks. The highest Shiwang peak is 1342 meters above sea level. The total area of Jiuhua Mountain area is about 120 square kilometers, roughly in the south-north direction, between 117 ° 43 ′ - 118 ° 80 ′ E and 30 ° 24 ′ - 30 ° 40 ′ n.

From the foot of the mountain to Tiantai peak, there are many famous temples and ancient temples. There are 78 ancient temples such as Huacheng temple, Yueshen temple, Huiju temple and Baisui palace. There are more than 1500 Buddha statues. There are more than 1300 cultural relics such as imperial edicts, scriptures and other jade seals and magic weapons issued by Emperor Wanli of the Ming Dynasty.

In 2006, Jiuhua Mountain scenic spot, with Jiuhua Mountain as the main body, was rated as the national key scenic spot. In 2007, Jiuhua Mountain scenic spot was rated as national AAAAA scenic spot. In 2009, Jiuhua Mountain was named National Geopark. On April 17, 2019, UNESCO announced the approval of Jiuhua Mountain as a World Geopark.

Geology and geomorphology

geological structure

Jiuhua Mountain is one of the three major mountain systems (Huangshan, Jiuhua, Tianmu and Baiji) in southern Anhui. It is located in the middle of the lower Yangtze platform depression of the Yangtze paraplatform. Fold and fault structures are well developed in Jiuhua Mountain area, and magmatic activities are frequent. The main body of Jiuhuashan is a strong fault uplift belt composed of granite body. The marginal area of Jiuhuashan is mainly a slight uplift belt of fold fault block composed of granodiorite, except for some sedimentary rocks.

The strata in Jiuhua Mountain area are mainly composed of black siliceous carbonaceous shale, greyish green shale, argillaceous limestone, argillaceous banded limestone, grey thick bedded limestone, yellow green silty shale and fine sandstone from Cambrian to Silurian of Paleozoic. They all form the low mountains and hills around Jiuhua Mountain by folding or fault block uplift. Most of Jiuhua Mountain area is composed of intrusive rock mass, and the main part is composed of Yanshanian Jiuhuashan granite body, which intrudes along the center of Qingyang rock mass and extends nearly east-west. Most of the contact surfaces of the rock mass are extroverted, with an inclination of 40-50 ° and contact with the surrounding rock. The width of the contact surface is several hundred meters. The rock mass can be divided into three facies zones according to its structure and composition. The central facies is dominated by coarse medium grained porphyritic monzogranite; the transitional facies is dominated by medium grained granite, which constitutes the main body of the rock mass and has the widest distribution area; the marginal facies is undeveloped, which is generally several meters to 500 meters wide and mainly consists of fine grained granite. The main mineral composition is potash feldspar, plagioclase, and a small amount of biotite and amphibole.

The Jiuhuashan granite body forms a central canyon area with steep overhanging, in which most of Jiuhua's strange peaks and rocks are distributed. Qingyang rock mass is distributed in the periphery of Jiuhuashan, formed in the Late Triassic Indosinian movement. The rock mass itself is Jiuhuashan rock mass intrusion failure and incomplete. The intrusion surrounding rock is lower Paleozoic, the contact surface is extraverted, and the contact zone has obvious metamorphism. According to the rock composition and structure, it can be divided into three lithofacies belts. The central facies is dominated by monzonitic granite; the transitional facies is dominated by medium fine grained granodiorite, accounting for more than 70% of the exposed surface of the rock mass; the marginal facies is dominated by fine grained granite, tens of centimeters to tens of meters wide. The main minerals are plagioclase, potash feldspar, quartz and a small amount of biotite and amphibole. The geomorphic landscape is mainly composed of low hills and low mountains, which is in sharp contrast with the middle mountain landform formed by Jiuhuashan granite.

Jiuhua Mountain is a multi cycle tectonic movement area in the long geological river. From the Paleozoic to the early Mesozoic, Jiuhua Mountain was in a stable coastal or shallow sea environment, just like the vast area of Southern Anhui Province. The depth of the sea water was not big, and the slight rise and fall of the crust made the sea water advance and retreat frequently, but basically did not go beyond the sea environment. During this period, the deposition maintained continuity and integrated contact, and the total thickness of sedimentary rocks could exceed 10000 meters. There is no obvious folding and magmatic activity in this stage, but the changes of sedimentary facies and thickness can reflect the evolution of uplift and depression center. In the early Mesozoic (middle and Late Triassic), the Indosinian movement took place in the geological history, which had a great influence on the Jiuhua Mountain area. Not only the strong folding movement and magmatic activity took place, but also the Canghai sea became a land. In the middle and late Mesozoic, Jiuhuashan was disturbed by Yanshanian movement, especially in the second stage of Yanshanian movement. Not only the fault block activity was significant, but also the magmatic activity was active, which led to the intrusion of Jiuhuashan granite into the Indosinian Qingyang pluton and the occurrence of strong domed fault block uplift, which laid the foundation for the embryo of Jiuhuashan. In the early and late Cenozoic, the intermittent fault block movement occurred again in Jiuhua Mountain area. Especially during the Himalayan movement, Jiuhua Mountain uplifted several times and its height increased significantly, which made the mountain have multi-layer structure. The sedimentary rocks on the Jiuhuashan granite body are washed away, and the deep granite stands out, forming the rudiment of Jiuhuashan. After the late Cenozoic, the neotectonic movement of Jiuhua Mountain was very active, Jiuhua Mountain uplifted sharply again, and promoted the external force to cut along the granite faults, joints and other weak links. Therefore, Jiuhua mountain formed a landscape of scattered mountains, steep peaks, steep rocks and deep valleys.

topographic features

Jiuhua Mountain was originally a solid rock mass lying underground, but later it was dismembered into various kinds of rock peaks. Although the granite body is very hard, there are cracks to follow. Rainwater and surface water scour along the cracks and gradually decompose it. The Jiuhuashan granite body, formed between 8000 and 135 million years ago, is a melting magma with a high temperature of more than 1000 ℃ in the deep underground. It rises along the fault and intrudes into 3000 to 4000 meters below the ground to solidify, resulting in the effect of thermal expansion and cold contraction, that is, the magma is cooled externally, the internal temperature is high, and the expansion and contraction is uneven, forming the primary fracture joint in the rock body. After the formation of the rock body, it is affected by many tectonic movements, Some secondary joints, i.e. flaky joints, are formed during weathering.

The main joint groups in Jiuhua Mountain are near EW, near ns, 150-330 °, 60-240 °, 75-255 ° and 105-280 ° respectively. In addition, the rock mass is cut by NNE trending zhonglongshan Jiuhuajie fault, Tiejia thrust, Shixing yaotou fault, NE trending lingyangzhen lingshangsu fault, wuxiqiao fault and chaquanling fault. Although the granite in Jiuhua Mountain is very hard, there are many large and small rock crevices, which are full of scales and bruises, which are very conducive to the process of water erosion and weathering and denudation. The huge mountain is separated and dismembered, forming large and small stone peaks, cliff overhanging waterfalls on the peaks and deep valleys between the peaks.

The uplift amplitude of Jiuhua Mountain gradually decreases from the core to the edge. The peripheral mountain is composed of granodiorite and sedimentary rock with less hardness than granite, which is easy to be eroded. Therefore, the whole Jiuhua Mountain is composed of many high and low mountains and hills.

Zhongshan, located in the hinterland of Jiuhua Mountain, is more than 1000 meters above sea level, such as Shiwang peak (1342 meters), Qixian peak (1337 meters), Tiantai peak (1306 meters), Zhongfeng peak (1291 meters), Luohan peak (1280 meters), Baota peak (1229 meters), liantai peak (1218 meters), Dagu peak (1136 meters), shanglianhua peak (1048 meters), etc. The middle mountain of Jiuhua Mountain is mostly surrounded by cliffs, and there are many strange rocks on the top and slope. The reasons are as follows: on the one hand, the rising range is large, the cutting force is strong, especially in the high-lying areas, the frost effect is significant, and the damage degree of granite is far lower than that of mountains and hills; on the other hand, the joint groups are changeable and the density is different, and the joints are constantly weathered and denuded to the depth of the rock mass, forming a variety of strange rocks. For example, the "Eagle raking the wall" at the waist of Tiantai peak and the "one line of sky" at the top of the peak, the "five big Panshi" at liantai peak, the "big bell" at the top of Zhongfeng peak, the seven stone pillars at the end of Qixian peak and the "lotus lotus" at the top of Shanglian peak. The low mountain is located in the East, North and southwest of Jiuhua Mountain, with an altitude of 500-1000 meters. Its composition is variable, and its shape is also significantly different. The low mountain is composed of granite with steep slope and dangerous wall. For example, Zhaxiao peak (871 meters), Shamao peak (907 meters), zhonglianhua peak (937 meters), Cuifeng peak (738 meters), meimeijian peak (590 meters), etc. Compared with Zhongshan, which is composed of granite, the biggest difference is that the mountain is small, and the number of grotesque rocks distributed on the top and hillside is also significantly reduced. The low mountain composed of granodiorite has a ridge shape because of its weak lithology, few and sparse vertical joint groups. Some of them are narrow at the top and steep on both sides, such as huachengling (428-580m). Generally, the top of the ridge is wide, the slope is gentle, and the weathering overburden is thick, such as dalingtou (646-82)

Chinese PinYin : Jiu Hua Shan