What is the main reason for the formation of Yandang Mountain?

It is a volcanic eruption. According to the official website of the Wenzhou Municipal Culture, Radio, Television and Tourism Bureau, the four phases of volcanic eruptions have created the majestic landscape of Yandang Mountain. Its ruins will also become a natural window for exploring the tectonic magmatism and deep geology of the Asian continental margin, making Yandang Mountain a It is a unique Chinese famous mountain in the world that integrates landscape aesthetics, history, culture and natural science. In 2005, UNESCO declared Yandang Mountain a World Geopark. Yandang Mountain was formed 120 million years ago. It is the most complete and typical Solstice rhyolitic pyrosite in the volcanic belt on the Pacific Rim continental margin. It is called a "natural museum" by Chinese and foreign geologists. . Yandang Mountain, one of the first batch of national 5A-level scenic spots, is located on the northeast coast of Wenzhou City, Zhejiang Province. It has beautiful mountains and rivers and a picture of the sky. The mountain is named after the bird because "there is a lake on the top of the hillock, with reeds growing in the grass and wild geese sleeping there in autumn." Yandang Mountain has a beautiful landscape and is famous for its peaks, waterfalls, caves and peaks. It is known as "a famous mountain on the sea" and "a most beautiful place in the world". It is also known as "the first mountain in the southeast" in history. Part of Yandang Mountain is located in Yongjia County and Wenling City. It has a total area of ??450 square kilometers and more than 500 scenic spots distributed in 8 scenic spots. It is famous for its strange peaks and rocks, ancient caves and stone chambers, and waterfalls and flowing springs. Among them, Lingfeng, Lingyan and Dalongqiu scenic spots are known as the "Three Wonders of Yandang". Especially the night view of Lingfeng Peak and Lingyan Flying Crossing are the best in China.