Geographical environment of Fushan Mountain

Fushan is located in the western edge of the Lu (Jiang)-Zong (Yang) volcanic basin, close to the southeast of the Tan (Cheng)-Lu (Jiang) deep fault zone.

The Lu (Jiang)-Zong (Yang) volcanic basin was formed in the early Yanshan period. Since Mesozoic, volcanic rocks with the thickness of 1 100-3600 meters have been ejected from the basin. According to the geological age, it is divided into four eruption cycles (stages): Longmenyuan, Zhuanqiao, Shuangmiao and Fushan, and the volcanic rocks in each cycle (stage) are named after the group. The first three groups are volcanic rocks erupted in Jurassic (1.4- 1.95 million years ago), mainly coarse andesite, with occasional basalt. The latter belongs to Fushan Formation, and its geological age is Early Cretaceous.

Fushan is mainly composed of volcanic lava and pyroclastic rocks of Fushan Formation. From top to bottom, the rock types are: light purplish red thin tuff, light red and fleshy red massive coarse tuff breccia, fleshy red massive coarse tuff ignimbrite, light fleshy red massive coarse tuff, breccia aggregate and coarse tuff. * * * The thickness is about 100 meter. There are sporadic and fine magmatic rocks (syenite and syenite porphyry) invading the volcanic rocks.

Fushan is an ancient crater, which belongs to the caldera. Volcanoes have a complete mechanism and a typical shape. The crater is approximately circular, with a diameter of about 4 kilometers and an area of about 14 square kilometers. The volcanic mechanism is a basin-shaped depression, and the ridges of the surrounding hills are distributed in a ring or arc shape. Volcanic rocks strike curved and dip inward. The rock mass is a stream surface structure of lava flow, with an edge dip angle of 50-74 degrees, which slows down rapidly inward, only inclining to the center by several degrees to more than ten degrees.

From Foshan-Sun Jiafan-Zhoujiatan, there is an east-west fault zone, which is 25 kilometers long and 5 kilometers wide. There are three groups of small faults in Fushan crater, which are NNW, NNE and NNE respectively, and the rocks are criss-crossed. Fushan landform unit belongs to Jiangbei hilly area in the plain area along the Yangtze River. Fuhuan Mountain, Shamao Mountain, Tudi Mountain and Chashan form an open basin. The highest elevation of Fushan Mountain is165m, and most peaks are around100m, belonging to volcanic hills. The mountain is roughly distributed in the north-south direction, slightly higher on the east side, and descends from the highest peak Miao Feng to the north and south in turn until the height of the marginal zone is only about 60 meters, the elevation of both sides is 40-50 meters, the main peak is only 93 meters, and the extension part is below 20 meters.

The top of Fushan Mountain is flat, but there are many cliffs and valleys, which are all caused by fault cliffs and fault valleys formed along annular and radial faults. Especially the steep walls on the east and west sides are towering and abrupt, steep and spectacular.

The volcanic cones formed in the later period are small, and most of them are distributed in a semicircle around the Lushan crater. Epigenetic craters can be seen in Tianchi, Lotus Peak and rotten Keshi. The largest is Tianchi, which is 35 meters long and 24 meters wide. It covers an area of 840 square meters.

Qian Shan, west of Fushan Mountain, is a rare volcanic clock with vertical columnar joints on the rock wall. The low hills on both sides form a volcanic ring. There is a ridge composed of lava in the northwest, with an altitude of 25 meters, a length of 500 meters and a slope of about 5.

After the formation of colorful volcanic landforms, under the impact and dissolution of Proterozoic ancient lakes, 72-hole volcanic caves with 36 rocks in Fushan were formed, which were embedded in the waist of Fushan, dense and orderly. As the carrier of the cave-Qifeng, there are six famous people in Sanli.

In addition, the strange rocks in Fushan are dazzling. There are various stone scenes formed by volcanic pumice and gravity collapse, such as Tiansheng Bridge, Jade Rabbit Yue Bai Stone and Hundred Buddhas. There are also various elephant stones formed by spherical weathering and differentiation, such as parrots and swans, or dragons, phoenixes, elephants and turtles, which are very vivid. There are waterfalls, stone wells and so on. , strange and spectacular. Foshan belongs to the monsoon humid climate zone with the transition from north subtropical zone to middle subtropical zone. Four distinct seasons, mild climate, abundant sunshine, long frost-free period, abundant rainfall and obvious monsoon climate.

Fushan is one of the rainstorm centers in Zongyang County, with the maximum rainfall of 2 14.7mm, which mostly occurs in July. At this time, the surrounding rivers and lakes are full, forming a spectacle of "water flooding and floating mountains". After the plum rain, the temperature increased and the rainfall decreased. There was a rainstorm in August, but it was short-lived. Autumn rainfall is less, accounting for 16% of the annual rainfall, and there are many sunny days, which is a good opportunity for tourists to climb mountains and enjoy the scenery. There is less precipitation in winter, accounting for 1 1% of the annual precipitation, and the least in 65438+February, with an average of only 37 mm, sometimes accompanied by snowfall. Every year, the first day of snowfall is about 65438+February 12, the whole day of snowfall is about March 8, and the average number of days from beginning to end is about 138. The winter of March 9 is the best time to watch the "icicle sky" on Fushan. Fushan is located in the transition zone from north subtropical zone to middle subtropical zone, and the zonal vegetation type is deciduous-evergreen broad-leaved mixed forest zone. Because of the destruction of native vegetation, coniferous forests dominated by artificial Pinus massoniana, Chinese fir and black pine are dominant. Followed by natural secondary deciduous broad-leaved forest and mixed coniferous and broad-leaved forest with oak as the main species and a small amount of evergreen broad-leaved trees. There are more than 100-year-old trees before and after the temple, such as Holly behind Huayan Temple, Podocarpus and Mubi tree in front of Jinguyan Rock, Ginkgo biloba and Holly in front of Huisheng Rock. , with quaint and peculiar growth, which are recorded in the old records. By the 1990s, there were 586 species of vascular plants in Fushan, and the forest coverage rate of major scenic spots reached 43%. The central scenic spot of Fushan Mountain includes five scenic spots, namely Jinguyan, Huishengyan, Gao Yan, Zhanggongyan and Houshan, with an area of 3.8 square kilometers, covering an area of 5,700 mu and a forestry land area of 3,502 mu. There are 2386 mu of forest land, and the forest coverage rate is 58%.

199265438+February, Fushan National Forest Park was approved by the State Forestry Administration, covering an area of 3834.438+03 hectares.