Landform classification index
Geomorphological types, surface morphological characteristics, altitude (m), relative altitude (m) and slope composition.
The mountainous area fluctuates greatly, extending linearly, with clear veins, strong cutting, exposed bedrock and obvious structural characteristics. Metamorphic granite in Zhongshan > 800 600 > 75.
500 ~ 800, 400 ~ 600 > 30 sandy shale sandy in middle and low mountains.
300 ~ 500 low-mountain metamorphic rocks
The hills are undulating, the veins are unclear, the hills are round at most, and many bedrock outcrops are < 300 150 ~ 200 15 ~ 25 red rock, granite and sand shale.
The hilly area is gentle and the cutting is not strong <100/kloc-0 ~ 60 <15 bedrock and quaternary materials.
Quaternary materials with plane < 50 < 5.
I. Mountainous area-erosion and denudation structure landform
The mountainous area is a zone where the crustal movement rose relatively after the neotectonic movement. It is formed by long-term erosion and denudation. The geological and structural features have a certain expression on the landform, and the main ridge lines and valleys extend in the same direction as the structural lines. Mountains are mostly distributed in the periphery of northeast, east and southeast. The mountainous area is 2240.86 square kilometers, accounting for 15% of the total area. According to the morphological characteristics, it can be divided into three subcategories: Zhongshan, middle and low mountains and low mountains.
Yaogu Mountain (126 1. 1m) and Dayun Mountain (909.7m) in Linxiang City, Zhongshan City, Xiang Si Mountain (957.2m) in Yueyang County, Mufu Mountain (1595.6m) and Li Anyun Mountain (. The main components are granite and metamorphic rocks. The altitude is higher than 800 meters, the relative height is higher than 600 meters, and the ground slope is greater than 50. The cutting is obvious, and the gully density of the river network is 3 ~ 6 km/km2, which is characterized by high mountains, deep valleys and steep slopes. Gullies are densely covered, and the development process of modern landforms is mainly pipeline erosion. The erosion of the valley source has reached the saddle of the pass, and the water system is dendritic and radial.
The middle and low mountains are the periphery of Zhongshan in Linxiang City, the extension of Wujianshan, Dayun Mountain and Xiang Si Mountain, the remaining veins of Mufu Mountain, the southwestern part of Li Anyun, Fuxing Mountain and Yuchi Mountain in Miluo City, etc. The main components are metamorphic rocks and granite. The altitude is 500 ~ 800 meters, the relative height is 400 ~ 600 meters, and the ground slope is greater than 30. Gully density of river network is 3 ~ 6 km/km2, and cutting is moderate. The formation process of modern landforms is mainly pipeline erosion. It is characterized by steep mountains, obvious ridges, clear veins and uncertain direction. Most of these ridges are smooth and uneven, and the mountains are pig's backs.
The residual top of Taohua Mountain in Huarong County, the periphery of Dayun Mountain, Mufu Mountain and Fuxing Mountain, Zhifeng Mountain in the southeast and northeast of Miluo City and Miyan Mountain, Piaofeng Mountain and Shending Mountain in the south. Both sides of Chang 'an Valley in Linxiang City, Mabu Mountain in Yueyang County and Xiao Mu Ridge in Yueyang Louqu all belong to low mountains and hills. The main components are granite, metamorphic rock, sand shale and glutenite. The altitude is 300 ~ 500m, the relative height is 20m, and the ground slope is 25 ~ 30. The cutting is slight, the gully density of river network is 4 ~ 6 km/km2, and the ridge veins are clear, but the trend is chaotic.
Second, the hills-erosion and denudation landform
These hills are located in the zone where the earth's crust rises slowly. The hilly area is 3435.98 square kilometers, accounting for 23% of the total area. According to the surface morphological characteristics, it can be divided into two subtypes: high hills and low hills.
High hills are generally distributed in front of the mountain or at the extension of mountain residual veins. The mountains composed of metamorphic rocks (or phyllite and slate) are distributed in, Hengpu and Nie in Linxiang City, Maotian, Acacia, Gongtian and Raocun in Yueyang County, and Tancheng, Wengjiang, Sanyang, Middle East and Li Anyun Mountain in Pingjiang County. Niujiao Mountain and Xiaomoshan in Huarong County, Zhanqiao, Baiyangdian and He Fan in Linxiang City, Maotian, Acacia, Gongtian, Gantian, Raocun and Fenghuang in Yueyang County, Nanjiang, Hongqiao, Zhezhuang, Hubei, Sicun and Ludong in Pingjiang County, and Bishi and Gaojia in Miluo City. In addition, there are east-west sand shale hills on both sides of Chang 'an Valley in Linxiang City. There are glutenite mounds in Jinlong and Dazhou in Pingjiang County, with an altitude of 200 ~ 300m, a relative elevation of 150 ~ 200m, and a ground slope of 20 ~ 25, which is locally greater than 25. Gully density of river network is 4 ~ 5km/km2. The hills are mostly in short strips, and the hills and gullies are slightly in strips and staggered. Gullies are mostly ridges and slopes are mostly dry land. The dome is round and muddy, the ridge is gentle, the bedrock is partially exposed, most of it is strongly weathered, and the slope remains are thick. The development process of modern landforms is dominated by pipeline erosion, with serious soil erosion.
Low mountains and hills are mainly distributed in the periphery of high mountains and hills and in the transition areas to hills. North of Dacheng Temple in Huarong County, Nie City in Linxiang City, Nanchong, Tian Yue, Huang An, Daduan, Gantian, Lantian, Weidong, Fenghuang and Wang Guan in Yueyang County, Sanyang, Wengjiang, Tancen and Zhongdong in Pingjiang County, and Honghua, Patio, Changle, Gulun and Baishui in Miluo City. In Taolin, Changtang, Zhong Fang and Baiyangdian in Linxiang City, and Changping Basin in Pingjiang County, there are low hills composed of red glutenite and shale. Dingshan and Shifushan in Huarong County, Baiyangtian, He Fan and Zhanqiao in Linxiang City, Maotian, Tian Wei, Raocun, Fenghuang and Xinkaitang in Yueyang County, Nanjiang, Hongqiao, Middle East, Cenchuan, Xijiang, Sicun, Ludong, Meixian and Hubei in Pingjiang County, and Huangbai and Hubei in Miluo City. In addition, both sides of Chang 'an Valley in Linxiang City are low mountains and hills composed of Sinian-Cambrian sandstone shale. There are low hills composed of tertiary red glutenite in Jinlong, Jiangshi and Dazhou in Pingjiang County. Yanglousi and Yunxi Districts in Linxiang City also have scattered low hills and hills composed of CAMBRIAN-Ordovician limestone and dolomite, with an altitude of 100 ~ 200m, a relative height of 60 ~ 150m and a ground slope of 15 ~ 20. Gully density of river network is 5 ~ 7km/km2. The hills are disorganized and directionless, mostly in the shape of steamed bread, with short ridges formed by domes. The top of the mountain is round, with hills and valleys interlaced, and the valleys between hills are relatively developed. They are planted as paddy fields, and some hills and slopes are dry land. The formation process of modern landforms is dominated by running water erosion, and gully erosion is strong, which leads to serious soil erosion.
Third, hills-erosion and denudation landforms
The bottom of the hill is located in the relatively stable zone of the earth's crust, which has been affected by flowing water erosion and physical weathering for a long time, with an area of 2689.03 square kilometers, accounting for 18% of the total area. According to its morphological characteristics, it can be divided into two subtypes: high hill and low hill.
To the north of Sanlangyan in Huarong County, red soil uplands consisting of reticulated red soil and gravel layers are distributed. There are 3 ~ 5 river terraces in Jishuling, Moshan, Xiaoershan and Fengshan, Taolin Temple in Miluo City, Fanjiayuan, Huotian, Huangshi and Gupei, and Anding, Sanyang and Chiayi in Pingjiang County. In Taolin, Changtang and Zhong Fang in Linxiang City, on the edge of Changping Basin in Pingjiang County, and in Dajing, Huangshi and Huotian in Miluo City, there are hills composed of purple sandstone, conglomerate, siltstone and mineral conglomerate. Highlands made of granite are distributed in Cenchuan and Xijiang basins in Pingjiang County, Chuanshanping, Gaojiafang, Bishi, Tongpen, Shaxi, Phellodendron amurense, Gulun, Changle and Tianjing in Miluo City, and both sides of granite valleys in the south of Linxiang City. Huanghushan and Fengshan in Huarong County, Tandu and Yuantan in Linxiang City, Kang Wang, Wujiang, Xitang, Kunshan, Matang, Longwan and Wuhuan in Yueyang County, Lishan, Tancen, Wengjiang and Sanyang in Pingjiang County, above the iron threshold on both sides of the Miluo River Basin, and northwest of Shending Mountain and Miyan Mountain. In addition, there are sand shale highlands in some areas of Tan Du, Chang 'an, Linxiang City, and gravel highlands along the Miluo River in Pingjiang County, such as papaya, Longmen, Jiangshi, Sicun and Ludong. The altitude is generally lower than 100 m, the relative height is 30 ~ 60 m, and the ground slope is 10 ~ 15. The gully density of river network is 4 ~ 6 km/km2. The columns are scattered in the shape of steamed bread or alternately arranged into ridge ditches, and the tops of the columns are uniform.
Hongshantou, Tashiyi, Sanfeng Temple and Zhongnan in Huarong County, Huangsha, Huangxiu, Daming, Jingzhou, Lujiao, Zhongzhou, Youai, Nakamura, Poplar, Shibu, Bear Market, Yanglin and Gongtian in Pingjiang County, Lishan, Sanyang, Anding and Chiayi in Pingjiang County, Xintang and Miluo City. In Taolin, Zhong Fang, Changtang, Baiyangdian, Chang 'an, Chengfeng in Linxiang City and Jing 'an in Xiangyin County, there are low hills composed of red rocks. In the north of Yalan-Dinghu Lake and the inside of Chang 'an Valley in Linxiang City, there are low hills composed of sand shale. The low hills composed of granite are distributed in Chuanshanping-Gaojiafang, Tongpen-Bishi Valley in Miluo City, both sides of the mountain transition and Baishui Town, Yuhua, Jinlong and Changkang in Xiangyin County. In the area south of Yalan-Dinghu Lake in Linxiang City, at the junction of the coastal plains of Mount Li, Tancen, Wengjiang and Miluo River and Zhifu Mountain in Pingjiang County, there are low hills and hills of metamorphic rocks (phyllite and slate), with an altitude of less than 60m, a relative height of 10 ~ 30m and a ground slope of 5 ~/kl. The development process of modern geomorphology is mainly water surface erosion and gully erosion. Gully density of river network is 2 ~ 3km/km2. The top of the mountain is flat, and the top of the mountain is mostly steamed bread-shaped, gently undulating and slightly inclined to the plain. The outside is bounded by the plain, and the turning point is obvious; The inner side is bounded by Gaogangdi and gradually transits.
Four, plain accumulation landform
The plain is mainly formed by long-term accumulation of alluvial sediments from rivers and lakes in areas where neotectonic movement is relatively declining. The area is 4033.55 square kilometers, accounting for 27% of the total area. Mainly distributed in Huarong, Yueyang, Xiangyin, Miluo County (city) and Qianlianghu, Quyuan, Jianxin, Junshan and Huanggaihu farms. The altitude is mostly below 50 meters, and the ground slope is less than 5, slightly inclined to Dongting Lake. Gully density of river network is 1 ~ 2km/km2. The ground is flat and open, with deep sediments and contiguous cultivated land. According to the surface morphological characteristics and material composition, it can be divided into three subtypes: river alluvial plain, lakeside alluvial plain and valley alluvial plain.
River alluvial plain is distributed on the right bank of the Yangtze River and downstream of Xiangjiang River, mainly including Jiangzhou, Ji Cheng, Tashi and a part of Hongshantou in Huarong County, Huanggaihu Farm in Jiangnan and Linxiang City, downstream of Xin Qiang in Yueyang County, Miluo River bank below Cao Jiashan in Miluo City, middle of Quyuan Farm, Tangsanhe and Dong Tang in Xiangyin County, and Shuiwei Road in Hunan and Zier. The surface material is mainly river alluvium, with an altitude of less than 40 meters and a slope of less than 5. The ground is flat and slightly inclined to the river.
The lakeside alluvial plain is distributed in the lakeside zone, mainly including the southwest of Huarong County, Guangxingzhou in Junshan District, Liangqian Lake, Jianxin, Junshan Farm, the east bank of Miluo River along Shile in Miluo City, the north and west of Quyuan Farm, and the west of Xiangjiang River in Xiangyin County. The surface materials are mainly composed of river alluvium and Dongting Lake sediments. The altitude is generally lower than 30 meters, the slope bottom is less than 3, and the terrain is low and flat. Huzhou, floodplain and wetland are widely distributed.
Valley alluvial plain is developed in hills and hilly valleys. The eastern mountainous area is the birthplace of the stream, with short flow, small flow, strong erosion and few floodplains. The hilly area is characterized by small topographic slope, wide valley, meandering development and dominant river deposits, forming a valley plain composed of alluvial deposits and alluvial deposits. Mainly distributed in the outer edge of Taohua Mountain, on both sides of Taolin River, Yuantan River, Xindian River and Xin Qiang Valley, on both sides of Miluo River and its tributaries, and in Gangdixi Valley in the east of Xiangyin. The surface material consists of Holocene alluvium. The altitude is generally below 50 meters, and the surface is relatively flat, slightly inclined to the river bed. The slope is generally less than 3, and the part near the mountain can reach 5. Most valleys and plains have been turned into farmland.
Verb (abbreviation for verb) waters-rivers, lakes and ponds
Dongting Lake is located on both sides of the territory, the Yangtze River passes through the northern border of the territory, and Xiangshui and Hippo Chef Water enter from the southwest of Yueyang City. The terrain is high in the east and low in the west, with abundant rainfall. Therefore, the water system is developed, there are many rivers, lakes, ponds and reservoirs, and the waters are vast, so it is called "Dongting Water Town". The water area (excluding the outer lake) is 2539 square kilometers, accounting for 17% of the total area.
Dongting water system is dominant in the territory, and the drainage area accounts for 90.54% of the total area of the city, followed by Binjiang water system and Poyang Lake water system. There are 273 rivers and 0/65 lakes. There are also many small and medium-sized reservoirs with dense water diversion channels and many water storage ponds. The water surface in the eastern mountainous area is 285.20 square kilometers, accounting for 1 1.23% of the total water area, the water surface in the central hilly area is 543.74 square kilometers, accounting for 2 1.4 1% of the total water area, and the water surface in the western plain is17/kloc-. In addition, the surface area of the outer lake is about 290 square kilometers.