Thank you for the invitation. Plain terrain is one of the five basic terrains on the earth's land surface. It usually refers to a vast area with an altitude of less than 200 meters and a relatively flat surface. The world's famous plains include the Amazon Plain, the West Siberian Plain, the East European Plain, the Great Plains of North America, the Ganges Plain, the Northeast Plain and the North China Plain. Plains can be divided into independent plains and subordinate plains. All of the above plains belong to independent plains.

Weihe Plain Location Map

In addition, there are some plains that belong to some relatively larger terrain units, so they are called subordinate plains, such as the Chengdu Plain, the Ningxia Plain, the Hetao Plain and the Weihe Plain are all subordinate plains. The Weihe Plain is located in the northern part of my country. The northern part of the plain is connected to my country's Loess Plateau, and the southern part of the plain is distributed with the east-west Qinling Mountains. The entire Weihe Plain is also oriented east-west, extending about 300 kilometers from east to west, with a total area of ​​36,000 square kilometers. It is the fourth largest plain in my country.

Weihe Plain (Guanzhong Plain)

The terrain of the Weihe Plain is higher on the north, southwest and east sides, and relatively lower in the east. It is connected to the North China Plain after passing through Hangu Pass (later called Tongguan) in the east. The Weihe Plain is located west of Hangu Pass, so it is also called the "Guanzhong Plain". In terms of topography, this area is very consistent with the characteristics of a basin, so it can also be called the "Guanzhong Basin". The formation of the Weihe Plain is the result of the combined action of internal and external forces. From the perspective of internal forces, there is an east-west Fenwei Fault Zone in this area. The rock layers move along the fault zone. The rock layers to the south of the fault zone rise relatively, forming a horst, which is the fault-block mountain Qinling; the rock layers to the north of the fault zone drop relatively, forming a graben, which is the Weihe Plain.

Location map of the Fenwei fault zone

So, from the perspective of geological structure, the Weihe Plain belongs to a "graben-type tectonic plain". Due to the low terrain in the graben, surface water converges inward, thus forming the Weihe River flowing from west to east. The silt carried by the Weihe River system is continuously deposited in the graben, eventually forming the alluvial plain "Weihe Plain" we see today. From ancient times to the present, the Weihe Plain area has been an important agricultural production area. It has fertile soil, flat terrain, and abundant water resources. It is known as "the golden city of thousands of miles, the land of abundance". The Weihe Plain area has a long history and is one of the birthplaces of Chinese civilization. Xi'an, the capital city of Shaanxi Province, is located in the Weihe Plain.

Distribution map of passes around the Weihe Plain