Introduction:
Xi 'an, formerly known as Chang 'an and Haojing, is now the capital of Shaanxi Province, a sub-provincial city and a national regional central city. It is an important central city in western China approved by the State Council and an important scientific research, education and industrial base of the country. Xi is one of the four ancient capitals in China, a "world historical city" determined by UNESCO 198 1, and one of the top ten ancient capitals in the world selected by American media.
Organizational evolution:
After the founding of People's Republic of China (PRC), Xi's administrative subordination and administrative divisions have undergone several major changes and adjustments. Xi 'an was liberated on May 20th, 1949, which belongs to the municipality directly under the Central Government of Shaanxi-Gansu-Ningxia Border Region. 1950 was under the leadership of the Northwest Military and Political Committee, 1953 was under the jurisdiction of the Northwest Administrative Committee, and Xi 'an was the Northwest Administrative Committee. In March 1953 and 12, it was changed into a municipality directly under the central government and became one of the municipalities directly under the central government in China 12; 1954 June19 changed to provincial capital city.
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The geological structure of Xi 'an is divided into two units: Qinling geosyncline fold belt and North China platform. 65.438+0.3 billion years ago, during the Yanshan Movement, a big fault occurred at the northern foot of Qinling Mountains. Since the Neogene about 3 million years ago, the neotectonic movement in the Qinling geosyncline fold belt south of the great fault has been extremely active, and the mountains have fallen sharply from north to south, creating the Qinling Mountains. At the same time, the Weihe fault depression, which belongs to the North China platform to the north of the great fault, continued to subside, and the Weihe plain was formed under the joint action of aeolian loess cover and Weihe alluvial.