Tengchong volcano actually looks like Yunnan's "mushrooms"? And they are in pairs!

Tengchong City in Yunnan Province of my country was called "Dianyue" in the Western Han Dynasty. In 1913 (the second year of the Republic of China), it was renamed Tengchong County. It is now a county-level city under the jurisdiction of Yunnan Province. The volcanic group formed in Tengchong City since the Cenozoic Era (Tengchong Volcanic Group) is one of the largest active volcanic groups in my country, including about 97 volcanoes. Volcanic eruption activities began in the Miocene and continued to the Holocene.

All of these volcanoes are located on the west side of the Gaoligong strike-slip fault zone, and are regularly distributed from north to south in a narrow northeast-northeast arc basin. The lava distribution area in the volcanic area is about 792 square kilometers.

Among them, Heikongshan Volcano (the latest activity time is about 3600 years ago), Dayingshan Volcano (the latest activity time is about 2018) and Maanshan Volcano (the latest activity time is about 2500-3000 years ago) are the three active volcanoes in the volcanic group that have erupted in the Holocene period.

The complex tectonic geological background has resulted in a large number of fault structures in the Tengchong area. The formation and eruption of the Tengchong volcano group are mainly controlled by the faults in the basin. The multiple magma eruptions and tectonic cycles in the volcanic area have created a wonderful volcanic natural landscape. The relative positions and spatial distribution of volcanoes in the volcanic group are arranged regularly, just like the "fungi" growing in Yunnan.

Location map of some volcanoes in the Tengchong volcanic group in Yunnan Province (the left picture is from GF-2 earth observation image; the middle picture is from the National Geographic Information Public Service Platform; the right picture is from GF-2 earth observation image)

Wild porcini mushrooms in Yunnan (Photo from the Internet)

The eruption process of the Tengchong volcanic group can be roughly divided into the early shield-building stage, the middle cone-building stage and the late explosive eruption stage. The volcanic landforms mainly include volcanic cones, craters, lava terraces and fumaroles. The rock types are mainly basalt, trachyandesite and dacite. Other volcanic eruption products include lava, volcanic breccia, volcanic ash and volcanic bombs.

There are more than 80 gas springs, hot springs and hot springs in the volcanic area, which is the second largest hot gas field in my country. Among them, the Liuhuangtang Dagunguo Hot Spring, Huangguaqing Hot Gas Ditch and Zaotanghe Hot Spring are more famous. The Liuhuangtang Dagunguo Hot Spring is circular, with a diameter of about 6 meters and a depth of about 1.5 meters. It is surrounded by 8 semicircular stone slabs. It has hot waves and steam all year round. The water temperature is as high as 96.6℃. It is commonly known as the "Big Gunguo" locally; its temperature is lower than the jet temperature of the Sofataria fumarole of the Campi Flegrei super active volcano in Italy (144-163℃), but significantly higher than the gas temperature of the Julong Hot Spring of the Tianchi Volcano in Changbai Mountain, my country (70-75℃).

The location map of Xiaokongshan, Heikongshan and Dakongshan volcanoes in the Tengchong volcanic group (left picture from the Internet) and Chengzilou volcano (right picture from the Internet)

Hot springs in the Tengchong volcanic area (first and second from the left, pictures from the Internet), hot springs in the Campi Flegrei super active volcano area in Italy (second from the right, original pictures) and hot springs in the Tianchi volcanic area in Changbai Mountain (first from the right, original pictures)

Existing observation data of the Tengchong volcano group show that the geothermal activity in the volcanic area is very active, hot springs, boiling springs and fumaroles can be seen everywhere, and volcanic gases such as CO2, H2S, N2, H2, CH4 and SO2 are released. There are magma sacs within a range of about 6-16 kilometers at the bottom of the volcano group, and satellite ground observation thermal infrared image data also show that there may be multiple magma sacs at the bottom of the volcanic area.

The microseismic activity in the volcanic area is relatively active, mainly tectonic earthquakes. From January to June 2023, a total of more than 280 microseisms occurred, with the largest earthquake magnitude being ML2.8 (data from the Institute of Volcanology, China Earthquake Administration, Yunnan Provincial Seismological Bureau and Institute of Geology, China Earthquake Administration). Historical crustal deformation data in the volcanic area show that the local deformation anomalies in the volcanic area are mainly caused by the activity of magma sacs and magma degassing at the bottom of the volcanic group. The above evidence fully demonstrates that the Tengchong volcanic group is a large active volcano group.

Compared with the large active Stromboli volcano in Italy, which has been undergoing gentle "Stromboli-style" eruptions all year round, the Tengchong volcanic group displays a unique "gentleness", while compared with the large active volcano Tianchi in Changbai Mountain, my country, it appears much more "violent".

Xiaokongshan and Heikongshan volcanoes in the Tengchong volcanic group in Yunnan Province (left picture from the Internet), Stromboli volcano in Italy (center picture, original picture) and Tianchi volcano in Changbai Mountain, Jilin Province (right picture, original picture)

The Tengchong volcanic group is the most concentrated, spectacular and typical volcanic geothermal area in my country, and is a precious legacy left to us by Quaternary volcanic activities. The leisurely time of Tengchong Ancient Town, the beautiful landscape of wetland ecology, the golden scenery in late autumn and the rich volcanic resources make the Tengchong volcanic group famous at home and abroad. It was listed as a national scenic spot in 1994 and approved as a national park in 1997. The Tengchong volcanic group is also part of the national 5A-level volcanic hot sea tourist attraction. The more concentrated volcanoes such as Dakong Mountain, Xiaokong Mountain and Heikong Mountain in the volcanic area are lined up from north to south. If you check in at the Hot Sea Scenic Area, Dakong Mountain and Xiaokong Mountain Scenic Area in the volcanic area, it will also be a deep integration of nature, history and culture.

In addition, there is a Blackfish River in the park, which is known as the "Tengchong Branch Island of Iceland". It is named "Blackfish River" because thousands of blackfish flow out of the outlet every summer and autumn. The Blackfish River is an underground river. The lava flow produced by the volcanic eruption blocked the groundwater channel, and the groundwater thus flowed out to the surface to form a river. The riverbed and surrounding rock types of the Blackfish River are mainly black basaltic lava. The Blackfish River under the clear sky is the same color as the mountains and rivers, and it is very photogenic! So, it is not that Iceland in Europe is unaffordable, but that the Blackfish River in Yunnan Province is more cost-effective!

Basaltic lava in Heiyu River, Tengchong volcanic area (left picture from the Internet) and basaltic lava in Tianchi volcanic area of ​​Changbai Mountain (right picture, original picture)

On the cliffs along the Longchuan River in the Tengchong volcanic area, you can see a number of basalt columnar joints that are tens of meters long. They are compactly arranged and stacked together in bundles, and are locally called "sacred pillars."

If the giant basalt columnar joints exposed in the Tianchi volcano of Changbai Mountain in my country show majestic grandeur, then the basalt columnar joints of the Tengchong volcanic group are even more splendid and gorgeous. The existence of this volcanic geological wonder not only enriches the natural landscape of the Tengchong volcanic group, but also has important scientific value for studying the genesis of the Tengchong volcano and the regional tectonic dynamics evolution.

The columnar joints of basalt are the most common type of joints in volcanic rocks. They are regular joints formed when magma overflows and cools rapidly. Generally, the columns of columnar joints are mostly perpendicular to the lava flow surface, but there are also horizontal, inclined or arc-shaped rotational joints. The temperature of volcanic magma during eruption is about 1200 ℃. When basaltic magma cools to 800-900 ℃, hexagonal columnar joints of basalt are easily formed.

Columnar basalt in the Tengchong volcanic area (left picture from the Internet) and columnar basalt in the Tianchi volcanic area of ​​Changbai Mountain (right picture, original picture)

Cross-border science

Yunnan Province in my country is known as the "Wild Mushroom Kingdom". There are about 2,500 species of wild edible mushrooms known in the world, and more than 900 species are found in Yunnan Province, accounting for about 36% of the global species and 90% of the national species. From June to September every year, it is the rainy season in Yunnan Province, and rainfall is relatively abundant in various places, providing good conditions for the growth of wild mushrooms. During this rainy season, various wild mushrooms have sprung up in the mountains and forests across Yunnan, giving pickers and diners a feast for the eyes and taste buds, but you need to be reminded: do not eat or buy and sell wild mushrooms at will! Avoid wild mushroom poisoning incidents. When eating wild mushrooms, you should do "four no's and one do": do not eat wild mushrooms in cold salad; do not mix and process multiple varieties of wild mushrooms; do not eat leftover wild mushrooms; do not drink alcohol; and eat them after they are fried and cooked thoroughly (data from CCTV News and Science Popularization China).

Some common poisonous wild mushrooms in Yunnan (Photo from the Internet)

This issue of science popularization ends! Friends, see you next time!

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Authors of this issue: Ye Xiqing, Sun Liying, Sveva·R·M, Gu Guohui, Alessandro·S, Emilio·C

Planning: Xu Zhitao, Stefano C Mimmo P, Francesco R Nikos S

Editor: Li Mengmeng, Song Yujia, Sun Zigang, Ma Xiaoxi

Review: Pan Xiaodong, Kang Jianhong, Cao Li, Chen Bo, Li Zhongwei, Chen Junjie, Zheng Guodong, Lu Yanhong, Wen Hongtao, Pang Jingyuan

Publicity: Guan Sheng, Xu Dan, Feng Jingqiao, Ma Fei, Jia Lin, Liu Hongyan, Chen Linrong, Liu Bingyang, Wang Jingwei, Xu Yueren, Zhang Kun, Sun Yonggang, Yu Lu, Zou Yaoyao, Xu Zhikai, Liu Chaoyang, Wei Meixuan, Zhang Renpeng, Xu Jingsi, Cai Shihao, Zhong Guangpei, Liu Songjun, Guo Feng, Han Di, Ren Fangyu, Li Yihong, Fu Shu, Qi Wei, Zhao Guohui, Kong Qingjun, Park Jie, Zhu Daqing

Produced by: Institute of Volcanology, China Earthquake Administration; Jilin Provincial Earthquake Administration; Italian Institute of Geophysics and Volcanology (Rome, Naples and Catania); Institute of Environmental Geology and Geoengineering, National Research Council, Rome, Italy; Institute of Forecasting, China Earthquake Administration; University of Science and Technology of China; Northeast Normal University; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences; Zhejiang University; China University of Geosciences (Wuhan); Institute of Oceanology, Chinese Academy of Sciences; Tengchong Earthquake Monitoring Center, Yunnan Earthquake Administration

Disclaimer: All pictures and texts in this article are for public benefit and do not have any commercial value.