Where is the Loess Plateau located?

The Loess Plateau is in the transition zone from coastal to inland. Transition zone from plain to mountain plateau; In the transition zone from humid area to arid area; In the transition zone from forest to grassland; In the transition zone from agriculture to animal husbandry.

The Loess Plateau is one of the four plateaus in China. Due to the influence of geographical location, climate, height, precipitation and other factors, the Loess Plateau has a unique landform. Let's talk about where the Loess Plateau is.

0 1 Loess Plateau is located in the north-central part of China, which is one of the four plateaus in China. The loess plateau in a broad sense is the loess area, covering an area of 635,000 square kilometers, including 38 1.000 square kilometers of primary loess and 254,000 square kilometers of secondary loess, which are mainly composed of Shanxi Plateau, Shaanxi-Gansu-Shaanxi Plateau, Longzhong Plateau, Ordos Plateau and Hetao Plain. In a narrow sense, the Loess Plateau starts from the Great Wall in the north, the Qinling Mountains in the south, Wushaoling Mountain in the west and Taihang Mountain in the east, including most of Shanxi, north-central Shaanxi, central and eastern Gansu, southern Ningxia and eastern Qinghai, covering an area of about 300,000 square kilometers.

The Loess Plateau is an important energy and chemical base in China. Loess has fine particles, soft soil and rich mineral nutrition, which is beneficial to farming. Basin and valley agriculture has a long history. Except for a few rocky mountains, the thickness of loess is between 50 and 80 meters, and the maximum thickness is 150 ~ 180 meters. On the loess plateau, the unique culture of the yellow land was bred, and the folk houses represented by "cave dwellings" and folk literature and art represented by Xintianyou and Ansai waist drums were produced.

The bedrock structure of the Loess Plateau is divided into two parts with Liupanshan as the boundary, the western part belongs to the western land mass and the eastern part belongs to the North China land mass. The loess plateau to the west of Liupanshan Mountain is characterized by Cenozoic faulted basins, and the underlying bedrock of loess in Longzhong Basin is Gansu Group from Miocene to early Pliocene, which is directly accumulated on ancient rocks. After the accumulation of Gansu Group, the ground uplifted in the late Pliocene, and the Yellow River and its tributaries Taohe River, Zuli River and Hulu River cut down with the uplift, and the bedrock ground became hills.

The loess plateau is an active area of neotectonic movement, which is mainly characterized by intermittent large-scale overall uplift of the plateau, while the surrounding depression areas are constantly sinking. Judging from the fact that there are 3 ~ 4 terraces in the valleys in the vast area of the Loess Plateau, the uplift of the Loess Plateau since the Quaternary is the main reason, and the uplift range is 150 ~ 30 meters. Crustal uplift is beneficial to the development of river undercutting and erosion landform, and also to the strengthening of soil erosion process. Liupanshan Mountain in the Loess Plateau is the uplift center of neotectonic movement. According to modern leveling, the rising speed is 20mm/year. The uplift in the west of Liupanshan Mountain is greater than that in the east, and the fastest uplift is in huajialing. According to the leveling of Longhai Railway 1934- 1955, the modern uplift speed in Longxi and Weiyuan areas is 3 1.4mm/ year, and the cutting speed under ditches in Longde and Zhuanglang areas is 45 ~ 240 mm/ 1955.

The geographical position of the Loess Plateau is in the transition zone from coastal to inland and from plain to plateau. It crosses warm temperate zone and middle temperate zone from south to north and semi-humid and semi-arid dry-wet zone from east to west. The eastern and southern parts of the plateau belong to warm temperate semi-humid areas, the central part belongs to warm temperate semi-arid areas, and the western and northern parts belong to mid-temperate semi-arid areas. The climate of the Loess Plateau is not only influenced by latitude and longitude, but also restricted by topography, which has typical continental monsoon climate characteristics.

There is a great difference in precipitation between the eastern and western parts of the Loess Plateau, because it is located in the eastern monsoon region of the mid-latitude belt and belongs to the south of the westerly belt prevailing at high altitude. Winter is controlled by Mongolian high pressure, and the polar continental air mass moves southward, which leads to cold and dry climate and less precipitation in the Loess Plateau in winter. In spring, due to the weakening of winter wind, the weak warm and humid air flow in the Pacific Ocean is still difficult to affect this area, resulting in obvious atmospheric and soil drought and serious spring drought. In summer, the surface of the Loess Plateau is in front of the continental thermal depression trough, while the upper air is under the influence and control of the subtropical high. The tropical marine air mass prevailing in the Pacific Ocean has a high humidity, which is stimulated by cold air to form a large area of precipitation, becoming the main source of precipitation in the Loess Plateau. In autumn, warm and humid ocean air moves south, and cold air enters the Loess Plateau. However, because the warm and humid ocean air retreating to the south was blocked by the Qinling Mountains, the metamorphic continental air mass quickly invaded, resulting in more frontal precipitation.