The occurrence of basalt is manifested in two ways of eruption:
Cracked eruption
It often constitutes a large area of ​​basalt basalt, and the fissure eruption channel often appears as a group of rock walls similar to the composition of basalt, but they are often buried by later rock currents and are not easily found. The Lushan basalt, which is widely distributed in southwestern China, is an example. It was formed in the Late Permian, with a distribution area of ​​about 260,000 square kilometers, generally 600 to 1500 meters thick, and the thickest part in the west is more than 3,000 meters. Basalt type, significantly rich in TiO2. In the basalt basalt, the average thickness of a single stream is about 10 to 100 meters, and the flow distance can reach 100 to 150 kilometers. Basalt in a region is often formed by several or dozens of eruptions, and the interval between eruptions can be long or short, and some can be hundreds of thousands of years.
Central eruption
It constitutes a basalt volcanic cone and its adjacent lava flows and pyroclastic rocks. In the eastern part of China, from Heilongjiang in the north to Hainan Island in the south, it is a composite rock zone with alkaline basalt and basalt. It is erupted in the Cenozoic, with a central eruption and hundreds of The volcanic cones are especially rich in Heilongjiang-Jilin, Inner Mongolia Plateau, Jining-Datong, Nanjing, Yunnan Tengchong, Guangdong Leiqiong and Taiwan.
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