VOLCANIC ERUPTIONS RESULT IN EARTH-SHAKING AND ENVIRONMENTAL CHANGES

Volcanic eruptions are among the strong tectonic movements, which not only change geological structure and landscapes, but also result in environmental changes. A large number of volcanic ashes and volatile gases with water, carbon dioxide, halogens, sulfur and others can cause solid and liquid aerosol, which may destroy ozone layer and form a "parasol" leading to cooling and rainy weather lasted a couple of months or years. In term of long time scale there is a relationship between volcanic eruptions and climate changes, that is active volcanic eruptions usually occurred in worm climatic period (interglacial), and inactive volcanic eruptions usually accompanied with cold climate period (glacial). This regulation has been confirmed by volcanic eruptions occurred in China and the world. For example, the volcanic eruptions frequently occurred in Antarctic before 35 Ma, then had been low-spirited util the Quaternary, while ice sheet just formed after 35 Ma corresponded to inactive volcanic period. Comparing frequency of volcanic activities with tectonic events in China it can be seen that intensive volcanic activities constantly accompanied with tremendous tectonic events which change nature and environment. For instance, the volcanic eruptive upsurges of 45 Ma, 35 Ma, 13 Ma, 1.2 Ma and others can be found in Tibetan Plateau and East China, which just corresponded to collision between Indian and Eurasian Plates, opening of marginal seas, uplift of Tibetan Plateau and so on. These events basically changed Asian and global environment. Volcanic activities can also cause living to die out. Famous dinosaurs were died in the Cretaceous maar lakes in Liaoxi, Northeast China, which resulted in volcanic eruptions. The same situation occurred in the Miocene maar lakes in Shanwang, Shandong Province, East China.