Geographical environment of Xunwu County

Except for the pre-Sinian, Ordovician, Silurian, Permian, Triassic and Upper Tertiary, all the strata looking for Wu are exposed, but they are undeveloped and scattered. Sinian and Cambrian are a set of extremely thick shallow-sea clastic rocks, which are exposed in the county, Lanbei, northern He Ling, Jitan, Zhuotang and Laomu. The Middle-Upper Devonian is a coastal clastic rock, which was exposed in the Northern Liu Che. The bottom of Carboniferous is mainly composed of shallow beach facies carbonate rocks, which are sporadically exposed in the intermountain basins of Laomu and Baishitan. Lower Jurassic lacustrine clastic strata are exposed only in the south and Gao Huan. Upper Jurassic clastic rock formation in Shangjia and Dingtianyuan areas. Late Jurassic sandy shale is distributed in calamus township, which is a considerable uranium-bearing horizon. Cretaceous strata formed by clastic rocks of inland lakes are widely distributed in Gukenggang, Chetou and Liu Che. The Lower Tertiary is only exposed in Liu Che, Fang Qiu. Quaternary is mainly distributed on both banks of Xunwu River.

Tectonic Xunwu is located in the east-west complex structural belt of Nanling, with strong magmatic activity. The main belt structures are Shima, Reshui-Gukenggang, Ehu-Shipai, He Ling-Lanbei fault zone and Neocathaysian fault zone, such as Xiancheng-Ehu-Humentuo fault zone and Jitan-Fang Qiu fault zone.

Magma and migmatite are widely developed and distributed in Xunwu of igneous rocks, accounting for 80% of the county's total area. There are three diagenetic periods from Caledonian to Yanshanian. Mainly distributed in Datong, Acorus calamus, Baimianshi, Liu Che, Nanqiao, Shangjia, Xiaping, Lanbei, Jitan, Tongkeng and other places. Xunwu is connected with Wuyishan in the southeast and Jiulian Mountain in the northwest. The terrain is high in the northeast, northwest and southeast, inclined to the southwest, like a dustpan, and distributed step by step in Zhongshan, low mountains, hills and hills.

The altitude of the territory is 500 ~1000m, and the relative altitude is 200 ~ 500m. The lowest elevation is the West Valley of Yan Dou Village in the south, with an altitude of180m. The highest elevation in the east is Xiangshan retort, with the main peak elevation of1529.8 m. The riverbed of the county is 272 meters above sea level.

Mountain valleys account for 2.38% of the total area, hillsides account for 7.68%, hills account for 14.3% and mountains account for 75.62%.

The county is dominated by mountains and hills, with only narrow valleys along the river. From east to west, it can be roughly divided into two uplift zones, Wuyishan and Keelung, and the subsidence zone of the red bed basin in the south. Xunwu belongs to the south subtropical red soil region, with good soil fertility and generally acidic soil. According to altitude and geographical classification, there are six kinds of soils in Xunwu, including paddy soil, fluvo-aquic soil, purple soil, red soil, mountain yellow soil and mountain meadow soil, among which red soil is the most, with more than 2.7 million mu, accounting for 86% of the total soil area. Red soil is widely distributed in hilly areas. Its main components are iron oxide, alumina and timing. Strong viscosity and strong acidity, suitable for planting citrus, navel orange and other crops.

The search for Wu is mainly mountainous and hilly, of which the mountainous area accounts for 75.6% of the total area. The county is covered with mountains and peaks. According to statistics, there are as many as 908 peaks above 400 meters above sea level, including 30 peaks above 1000 meters above sea level. The main peaks in the county are Xiangshan Zan, Laoyashi and Bijiashan in the east; In the south, there are palms facing the sky and palms falling, and in the west, there is Zhang Guilong; There is Taiyangguan in the north, and the main peak of Xiangshan is at an altitude of 1529.8 meters, which is the first peak in Xunwu County.

The river network in Xunwu is dense and the water resources are quite rich. According to statistics, there are 547 rivers in the county, with a total length of 1.900 km, of which 73 rivers have a rainwater collection area of 10 km2. The larger rivers are Xunwu River, Chenguang River (Jinshui River) and Luotang River, among which Xunwu River and Chenguang River belong to Dongjiang River system, and Luotang River flows into Xiangshui in Huichang to the north, belonging to Ganjiang River system. Xunwu River originates from Yajiboshan, Santong Village, Sanbiao Township, and is about120km long. It runs through the county from north to south, flows through 9 towns of Sanbiao, Shui Yuan, Chengjiang, Jitan, Changning, Wenfeng, Nanqiao, Liu Che and Long Ting, and flows into Dongjiang at the exit of Yan Dou Village, Long Ting Township. Xunwu county is rich in mineral resources. More than 30 kinds of minerals have been discovered, including tungsten, tin, molybdenum, copper, lead, zinc, rare earth, niobium, tantalum, iron, cobalt, gold, granite, phosphorus, gypsum, clay, crystal, uranium and mineral water, among which rare earth is the main one. Rare earths are mainly distributed in He Ling, Nanqiao, Sanbiao and other mining areas in our county. The average grade of He Ling mining area is 0. 159%, the proven reserves are 239,400 tons, and the retained reserves are about 1 1 10,000 tons. The grade of Nanqiao mining area is 0. 149%~0. 189%, with proven reserves of109,000 tons and retained reserves of about 60,000 tons. The grade of Sanbiao Tuanshizhai mining area is 0. 102%, and the proven reserves are 0.73 million tons. Grade of Chengjiang Zuheng mining area: 0. 1 10%, with a reserve of 27,500 tons; Xiangshan mining area10200t.

The main nonferrous metal minerals are Luoshanfeng, lead-zinc mine and Laomu polymetallic mine. Among them, the total amount of gold, silver and lead-zinc mines in Luoshanfeng and lead-zinc mines is 654.38+10,000 tons. The copper grade is 0.42%~0.58%, and the metal content is 2066 tons. Zinc grade is 0.4%~0.48%, and metal content is 94 1 ton; The grade of tungsten is 0.07% ~ 0.28%, and the metal content is 1739 tons.

Black minerals mainly include: the proven reserves of Laomu Iron Mine are 63 1 10,000 tons (ore) with a grade of 20-30%; Average grade of Nanqiao placer iron mine 14.83Kg/m? The reserve is about 262,000 tons.

There are many kinds of nonmetallic minerals, including granite, limestone, crystal, phosphate rock, gypsum and porcelain clay. Among them, there are three granites with proven reserves: (1) Fuzuling granite in Shuiyuan Township, with a reserve of 870,000 m? . (2) Mabutan granite in Arqueros Township, with a reserve of 22.87 million m? . (3) Guangxi Zhumao Huaxing granite stone, with a reserve of 2.07 million m? .

Mineral water and hot springs mainly include: (1) Nanqiao phosphate rock back mineral water: borehole gravity flow: 256 tons/day. According to its chemical composition, its mineral spring type is strontium lithium silicate carbonated mineral water. (2) Zhonghe Minyure Hot Mineral Spring (river corner): flow rate: 737 tons/day, water temperature: 70-76℃. According to its chemical composition, its mineral spring type is lithium strontium mineral water. Dongjiangyuan County is rich in water resources. There are 547 rivers in the county, with a total length of 1.902km and a river network density of 0.823 km/km2. The water area of the county is 83 10.7 hectares, accounting for 3.59% of the total land area of the county, of which the river area is 2,247.8 hectares, accounting for 27% of the water area, and the tidal flat area is 56,500.

Rivers in the county can be divided into three major river systems according to river basins, namely Dongjiang River system, Xiangshui River system and Hanjiang River system. The county belongs to Dongjiang River system, with a total drainage area of 1964.79 square kilometers, accounting for 85% of the county's total land area. The river belongs to Xiangshui River system, with a total drainage area of 192.52 square kilometers, accounting for 8.3% of the county's total land area. The river belongs to the Hanjiang River system, with a total drainage area of 154.74 square kilometers, accounting for 6.7% of the county's total land area.

Xunwu is the birthplace of Dongjiang River. The whole county belongs to Dongjiang River system, and there are 60 rivers with a basin area of 10 square kilometers, among which there are 5 rivers with a basin area of 100 square kilometers, namely Xunwu River, Jianxi River, Horseshoe River River, Longtu River and Jinshui River. The Beiling watershed system of Xunwu Water is called "the source of Dongjiang", and Beiling water is also called Jiuqu water and Dingnan water. It originated from the main vein of Jilong Mountain in Sanbiao Township, Xunwu County. There are two small rivers in Xunwu County, namely Hudahe and Shangxiaba River. Because the basin area, river length and total water resources of Xunwu water are larger than those of Beiling water, Xunwu water is the source of Dongjiang, which is the mainstream, and Beiling water is the largest tributary of Xunwu water. The birthplace of Xunwu Water is the birthplace of Dongjiang River.

The river belonging to Ganjiang River system in Xunwu is called Xiangshui River System, which is distributed in the northeast of this county. There are 8 rivers with basin area greater than 10 square kilometers, of which 2 rivers are greater than 100 square kilometers, namely Luotang River and Shangjin River. Xiangshui River system is called Gongjiang River after meeting Mianjiang River in Huichang County, and Ganjiang River after meeting Zhangjiang River in Ganzhou City.

Xunwu belongs to the Hanjiang River system, but it does not merge into a main stream in the county and leaves the country at the county boundary. There are five rivers with an area of 10 square kilometers, which are mainly distributed in Danxi Township in the south and Xiangshan Township in the east.

The county's total hydraulic resources are 210.32 billion cubic meters, with theoretical reserves of10.25 million kilowatts and exploitable capacity of 90,000 kilowatts. There are more than 60 small hydropower stations 1.60, with an installed capacity of 93,500 kilowatts. The total number of power stations in Xunwu County ranks first in the province, and it is also an advanced county with electrification standards in China, and is known as "Jiangnan Hydropower County". Xunwu is "the hometown of tangerines in China", "the hometown of navel oranges in China", "the export base county of navel oranges in China" and "the green ecological fruit production county". It is the first in the province to achieve an agricultural population of 2 mu of fruit per capita, and it is a veritable fruit industry county and a strong fruit industry county. There are more than 500,000 mu of navel oranges in this county, and the output of navel oranges accounts for about one-third of the total navel oranges in southern Jiangxi.

The county's cultivated land area is 6.5438+0.89 million mu, and the mountainous area is 2.76 million mu, including 900,000 mu in Guo Yi mountainous area. Xunwu belongs to subtropical monsoon humid climate zone, with moderate temperature, abundant sunshine and rainfall, and large temperature difference between day and night. It is the best area to develop citrus and navel orange.

Rich mountain resources and suitable climate have brought about the great development of Xunwu fruit industry. There are more than 300,000 mu of fruit industry in the county, including 50,000 mu of fine orchards, 8 municipal fine orchards and 0/5 county fine orchards. From Chengjiang to Wenfeng and from Chang 'an to the county seat, a 200-mile-long fruit belt has been formed.

The unique climate has created the characteristics of Xunwu navel orange and citrus, such as rich flavor, seedless and residue-free, crisp meat, high sugar content, moderate sweetness and sourness, high soluble solids, natural color and bright luster, which made Xunwu fruit win the laurel in national competitions many times. Citrus "Xunwu 1 19" was rated as the national excellent product, early-maturing "Lion Head 1" won the bronze award of the national high-quality product at the National Agricultural Expo, navel oranges "Newhall" and "Naivorina" were rated as the national high-quality products for many times, and were designated as "virus-free high-quality export products" by the Ministry of Foreign Trade and Economic Cooperation. On the basis of existing varieties, new varieties have been introduced, such as Fuben, Qingjian and Huogu. Approved by the Agricultural Development Office of the State Council, the mother orchard of navel orange and citrus varieties has been settled in Xunwu, and the breeding and extension system of citrus varieties is being established.

Excellent quality makes Xunwu fruit deeply loved by consumers at home and abroad. Not only in Guangdong, Zhejiang, Shanghai, Beijing and other provinces and cities, but also exported to Southeast Asia, Singapore, Russia and other countries, making Xunwu "Guo Xin" brand famous at home and abroad. In 200 1 year, the county's total fruit output reached 90,000 tons, with a total output value of 204 million yuan, exceeding the total grain output value and becoming a pillar industry of county economic development. 20 1 1 year, the total fruit output of the county has exceeded 300,000 tons, and Xunwu has become the main producing area, core base county and leading county of Gannan navel orange, which is "first-class in China and world-famous". (Data 20 10) There are Han, Mongolian, Hui, Tibetan, Uygur, Miao, Yi, Zhuang, Buyi, Korean, Manchu, Dong, Yao, Bai, Tujia, Hani, Dai, Li, She, Kazak, Russian, Oroqen, Gao.