There is a volcano in Inner Mongolia that makes a heart shape. Don’t believe it? Look!

The Arxan-Chaihe Volcanic Group (also known as the Halaha River-Chuol River Volcanic Group) in Inner Mongolia Autonomous Region is located in the middle section of the Greater Khingan Range in my country. The volcanic group extends in a northeast direction. The volcanic group includes the Tianchi Volcano in Jierguo Mountain, the Woniupaozi Volcano, the Wusu Langzi Lake Volcano, the Arxan Tianchi Volcano, the Dichi Volcano, the No. 10 Valley Basin Volcano, the Xiaodonggou Volcano, the Yanshan Volcano, and the Gaoshan Volcano. Among them, the Arxan Volcanic Group is the seventh largest active volcanic group in my country. The volcano is mainly characterized by central eruption. It has about 46 volcanoes, 3 crater lakes, 1 Maar Lake and 7 volcanic barrier lakes. The volcanic landforms are mainly volcanic cones, lava flows, lava terraces, crater lakes, volcanic barrier lakes, etc., showing a variety of forms. The Arxan Volcanic Group covers an area of ​​about 3,500 square kilometers, ranking first in Asia and second in the world.

Location map of some volcanoes in the Arshan volcano group in the Greater Khingan Range (left, from GF-6 Earth observation images) and location map of the Arshan Tianchi volcano in the Greater Khingan Range (right, from GF-2 Earth observation images)

The eruption time of the Arshan volcanic group is generally between 2.04 million years and the Holocene. There are currently four active volcanoes in the Holocene, namely Yanshan Volcano, Gaoshan Volcano, Shipen Volcano and Xiaodonggou Volcano, all of which are located in my country. Scientists have conducted 14C age determination on the two active volcanoes, Yanshan and Gaoshan. The age results show that they are about 1990-1900 years ago, indicating that the most recent eruption of these two active volcanoes is about 2000 years ago or newer than 2000 years ago. The current seismic and volcanic observation and research data of the Arshan volcanic group show that there are still magma chambers in the middle and lower crust at the bottom of the volcanic group. From 2020 to 2023, there have been more than 40 earthquakes above magnitude 0 in the volcanic area, and radon, carbon dioxide, helium and other volcanic gases are still released in the volcanic area (data from the Institute of Volcanology, China Earthquake Administration, Institute of Geology, China Earthquake Administration and Jilin University). Therefore, the Arshan volcanic group is a veritable active volcano group.

Alpine volcanoes and basaltic lava flows of the Arxan volcanic group (original images) and Yanshan volcano of the Arxan volcanic group (original images)

Arxan is not actually a mountain, but a relatively young city located in the transition zone between forests and grasslands in the eastern part of Inner Mongolia Autonomous Region. Arxan City (county-level city) was established in 1996. Its full name is Harun Arxan, which means "hot holy water" in Mongolian. Regional tectonic movements and volcanic activities have bred a rare mineral spring group in the world in the Arxan volcanic area. Its hot spring types and quantity, spring water outflow and trace element richness make it one of the largest functional mineral spring groups in the world. The Arxan volcanic area has distinct four seasons. In spring, the winter snow melts, rivers and lakes regain vitality, and all things revive; in summer, the green is re-dyed, full of vitality, and the climate is pleasant. It is a good place to escape the summer heat; in autumn, the leaves are green, white, yellow, red, purple and other different colors, which are dyed under the blue sky and white clouds, and are particularly gorgeous; in winter, the gurgling water of the unfrozen river and the rime complement each other, and the snowflakes blown by the breeze are like a mountain ink painting.

The Arxan volcanic area in summer (first and second from the left, pictures from the Internet) and the Arxan volcanic area in autumn (first and second from the right, pictures from the Internet)

Among the Aershan volcanoes, Tianchi Volcano is the most famous. The Tianchi on the top of the volcano is 1,332.3 meters above sea level, lower than the Tianchi in Changbai Mountain, Jilin Province (2,189.1 meters above sea level) and the Tianchi in Tianshan Mountain, Xinjiang (1,910 meters above sea level). It is a high-level crater lake with a "heart" shape. The Aershan Tianchi is covered with silk and gauze in the mist, which is extraordinary, ethereal and blurred. The Aershan Tianchi Volcano interprets the beauty and charm of the earth to the starry sky, moonlight, and the Milky Way in the universe in a "heart" way. The Aershan volcanic area is located near 47° north latitude. July to August in summer is the peak tourist season in Aershan. In autumn, from mid-September to early October, the Aershan Tianchi Volcano is full of golden and colorful scenery, charming and unique.

Arxan Tianchi volcano in the sea of ​​clouds in summer and autumn (left and middle pictures, pictures from the Internet) and Changbaishan Tianchi volcano shrouded in clouds and mist in summer (right picture, original picture)

In May 2017, UNESCO approved the Aershan National Geopark as a World Geopark. The park has dense virgin forests, clear rivers and lakes, and the remains of the Aershan volcano group. It is known as "the most beautiful forest in northern China". You can choose to hike along the path in the forest to feel the beauty and mystery of nature; you can also choose to take a cable car to overlook the entire Aershan scenic area from the air and feel the magnificence and vastness of nature; you can also choose to ride or drive to touch every corner of Aershan and feel the tranquility and wonder of nature. Special reminder to you, if you plan to go to the Aershan World Geopark, please be sure to check these safety emergency precautions!

The scenery along the way of self-driving tour in Arxan Volcano Area (Photo from the Internet)

1. Traffic safety

The volcanic terrain in the Arxan World Geopark is relatively complex. Especially when traveling to some distant scenic spots, you should choose a means of transportation in good condition to avoid breakdowns on the road. Be sure to check the weather forecast before departure. If you encounter bad weather, such as heavy rain, fog, strong winds, etc., you should try to avoid traveling.

2. Water safety

The Arxan volcanic area is rich in rivers and lakes. The unfrozen river in the volcanic area is one of the sections of the Halaha River. This section of the river never freezes in severe winter and is also known as the "unfrozen river". The river is gentle and the scenery on both sides of the river is picturesque, making it very suitable for rafting. If you participate in wading activities, you should follow the guidance of professionals and wear a life jacket. Do not swim in waters that you do not understand or are dangerous. Do not go into the water without permission and do not take photos in dangerous places.

The non-frozen river in the Arxan volcanic area in summer (left picture, sourced from the Internet) and the non-frozen river in the Arxan volcanic area in winter (right picture, sourced from the Internet)

3. Tourism project selection

When traveling, you can choose to join a regular and qualified tour group or hire a local tour guide with a good reputation. They can provide you with professional explanations and travel guidance about the scenic spots, making your trip more enriching and safer. When choosing to participate in high-risk recreational activities such as rafting and adventure, you should choose carefully according to your physical condition. When riding amusement equipment, you should fasten your seat belt. Do not go to undeveloped areas privately when climbing outdoors, and sit firmly and hold on when taking the cable car. Avoid participating in strenuous or stimulating activities when you are in poor physical condition or in bad weather.

4. Natural disaster prevention

The temperature difference between day and night in the volcanic area is large, so you should add or remove clothes appropriately. Do not swim, dive, or boat in rivers or lakes without safety guarantees. Avoid going to unopened/undeveloped areas for tourism, exploration, hiking, camping, etc. During the rainy season, avoid going to areas with dangerous rocks and other collapse risks to prevent natural disasters such as landslides, rockfalls, mudslides, and mountain torrents.

5. Food safety

Arxan is part of the Mongolian Plateau. When you first enter the plateau, you should take a rest. Pay attention to food hygiene and avoid eating raw and cold food. In the local area, you can not only experience the rich and colorful folk culture, but also taste local delicacies such as blueberries, milk tea, milk tofu, hand-held meat, oat noodles, etc. Many delicacies will surely make you feel happy. For example, the blueberry ripening season in Inner Mongolia is concentrated in mid-to-late July to early August. The color is purple-blue, the flesh is delicate, the taste is sweet and sour, and the vitamin E content is higher than that of apples and grapes. It has rich nutritional value.

Inner Mongolia blueberries, milk tea, milk tofu and hand-held meat (Photo from the Internet)

6. Protect the wild ecological environment

The Arxan volcanoes are located in the Greater Khingan Range in the northern part of China. There are more than 70 species of wild animals, including red deer, black bears, roe deer, otters, etc. Whether you are exploring with friends or family, or enjoying the natural beauty of the Arxan volcanoes alone, we should all pay attention to protecting the wild ecological environment, not littering, not picking flowers and plants at will, and not trying to chase, catch, touch or feed wild animals.

Wild roe deer (front row) and wild gazelles (back row) in the Arxan volcanic area (photo from the Internet)

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

References in this issue:

[1] Lu Jiaxin, Yao Yuan, Liu Jiaqi, et al. Relationship between temperature changes recorded by branched-chain glycerol dialkyl glycerol tetraethers in sediments and volcanic eruption records in the Arxan region over the past 300 years[J]. Quaternary Sciences, 2021, 41(1), 11.

[2] Ding Ming and Li Ming. Four active volcanoes discovered in the Arxan volcanic group[N]. Xinhua Daily Telegraph, 2003, 2.

[3] Bai Zhida, Tan Qingwei, Xu Guiling, et al. Late Quaternary volcanic activity and neotectonics in eastern Inner Mongolia[J]. Acta Petrologica Sinica, 2012, 28(4), 9.

[4] Xu Zhitao, Li Mengmeng, Sun Jinggui, et al. Genesis and diagenetic geodynamic background of Middle Jurassic rhyolite in Deerbul area, Daxinganling[J]. Journal of Jilin University: Earth Science Edition, 2023, 53(3), 866-886.

[5] Hou Jie. Surface wave tomography of the Abagha, Arshan and Nuominhe volcanoes[D]. Beijing: Institute of Geophysics, China Earthquake Administration, PhD dissertation, 2023.

[6] Zhang Fengxue, Wu Qingju, Li Yonghua, et al. Deep velocity structure and volcanic genesis in the Greater Khingan Range volcanic area[J]. Chinese Journal of Geophysics, 2022, 65(4), 1271-1287.

[7] Xu ZT, Ye XQ, Pan XD, et al. Geochemistry of apatites from preshield and postshield basalts and their petrogenetic implications: A case study of the Naitoushan basalt and Heishigou dike in the Changbaishan Tianchi volcano, NE China[J]. Mineralogy and Petrology, 2024. Doi.org/10.1007/s00710-024-00863-4.

[8] Pan XD, Gui GH, Song YJ, et al. Investigation of hot spring gas components and soil gas fluxes in Arxan Holocene volcanic field, Inner Mongolia, NE China[J]. Frontiers in Earth Science, 2023, 11, 1174315.

Authors of this issue: Xu Zhitao, Sun Liying, Ye Xiqing, Rossella F, Alessandro S

Planning: Xu Zhitao, Stefano C, Daniel O, Mimmo P

Editor: Li Mengmeng, Song Yujia, Jia Lin, Jia Baojin, Bao Bao, Xiao Xi Wenya

Review: Pan Xiaodong, Kang Jianhong, Cao Li, Chen Junjie, Zheng Guodong, Lu Yanhong, Wen Hongtao, Pang Jingyuan, Chen Bo, Li Zhongwei, Xu Yueren, Zhang Peng, Zhou Yaoyao, Yu Lu, Zhang Kun, Sun Yonggang, Xu Zhikai, Wang Yun, Jiang Hui, Wang Wanfu, Huang Xiaolei, Zhao Chunhua, Tan Yuwen, Liu Yinan, Xu Jingsi, Sun Guojun, Gao Qiliang, Wang Lijuan, Kang Li, Zhao Guohui, Liu Hao, Park Jie, Kong Qingjun

Publicity: Gu Guohui, Guan Sheng, Feng Jingqiao, Jin Wenhu, Wang Jingwei, Cao Guangyuan, Xuan Licheng, Liu Hongyan, Zhang Rui, Zhang Hongyan, Liu Bingbing, Li Yanbo, Zhang Xiaoqiu, Lu Yuanming, Liu Libo, Zhang Peng, Mi Hongdong, Construction Committee, Teng Yuechao, Gao Xuejiao, Li Yuan, Cai Shihao, Li Guangsen, Tang Chuncheng, Yan Hengqi, Zhang Yu, Lu Han, Chen Chuang, Gao Jinzhe, Wang Yumeng, Peng Jianli, Chen Zhuo, Zhang Yu, Fu Qi, Miao Peisheng, Tang Yiran, Cao Rongji, Han Di, Sheng Qiang, Xu Dan, Guo Feng, Liu Songjun, Shi Honghao, Sun Wanting, Li Junyi, Zhu Daqing

Produced by: Institute of Volcanology, China Earthquake Administration, Jilin Province Earthquake Administration, Etna Observatory, Catania, Italy, Institute of Environmental Geology and Geoengineering, National Research Council, Rome, Italy, School of Earth Sciences, Jilin University, Institute of Geophysics and Volcanology, Rome, Italy, Naples Volcano Observatory, Institute of Forecasting, China Earthquake Administration, Shenyang Center of Geological Survey, China Geological Survey, China University of Geosciences (Wuhan and Beijing), Zhejiang University, Northeast Normal University, University of Science and Technology of China, Institute of Oceanology, Chinese Academy of Sciences, Inner Mongolia Autonomous Region Earthquake Administration, Arxan Volcano Earthquake Observatory, Songyuan Earthquake Monitoring Center, Jilin Province

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