How was China’s “Plant Pompeii” “built”?

According to Xinhua News Agency on September 3, the second batch of 100 World Geological Heritage Sites was announced recently. Three geological heritage sites in my country were selected, namely the Wuda Permian Vegetation Fossil Origin, Zigong Dashanpu Dinosaur Fossil Site and Guilin Karst.

The second batch of 100 world geological heritage sites was announced, and three geological heritage sites in China were selected ( Photo source: Xinhua News Agency )

Among them, the Wuda Permian vegetation fossil site in Inner Mongolia is known as the "Pompeii of Plants". How can a common open-pit coal mine fossil site be associated with Pompeii? Don't worry, let's walk into this group of plant remains hidden in the coal seam.

01 What is a geological heritage site?

The geological heritage site is a type of World Geological Heritage Site List created by the International Union of Geological Sciences . The inclusion of the site in the World Geological Heritage List represents that the region or geological site has a typical international geological scientific significance on a global scale. So far, the International Union of Geological Sciences has published two batches of geological heritage site lists.

Ten geological relics, geological parks or reserves in China have been selected, namely the Permian/Triassic mass extinction and "Golden Nail" in Meishan, Changxing, the Biruut high sand hills and lakes in Badain Jaran Desert, Inner Mongolia, the Early Cretaceous acidic igneous columnar joints in Hong Kong, the Shilin Karst in Yunnan, the Cambrian fossil site and fossil repository in Chengjiang, Yunnan, the Rongbuk Gorge detachment tectonic system in southern Tibet , and the Ordovician rocks of Mount Everest jointly declared by China and Nepal. In addition, there is this year's plant Pompeii - the Permian vegetation fossil site of Wuda, the Dashanpu dinosaur fossil site in Zigong, and the Guilin Karst .

In October 2022, seven geological sites in my country were successfully selected into the world's first batch of geological heritage sites (Image source: CCTV News screenshot)

Among them, there are national geological relic protection areas, world geological parks, world natural heritage sites, national geological parks, important landforms and geological activity processes, important paleontological relic groups, etc. It can be said that they are all the "Black Wood Cliff" or "Morning Star" in the geological world.

02 What is so special about the plant Pompeii?

A mountain is not famous for its height, but for the immortals living there. A city is not great for its size, but for its tolerance. The ancient city of Pompeii shocked the world because it completely preserved and recorded the urban structure and people's lifestyle of the ancient Roman period in the 6th century BC, providing important information for understanding the social life, culture and art of ancient Rome. It attracts tens of thousands of visitors every day and is known as a "natural history museum."

The ruins of the sanctuary photographed in the ancient city of Pompeii, Italy ( Photo source: Xinhua News Agency )

The Wuda Permian vegetation fossil site in Wuhai City, Inner Mongolia, also has a similar role and function - it fully records the Permian tropical coal-forming swamp forest , has the world's largest area of ​​ancient forest restoration, the richest collection of coal-forming flora fossil specimens, the oldest cycads, the richest Cucurbitales plant community, and the most fossil plant reconstructions [1]. It is the world's most complete reconstruction of fossil plants. The holy land of paleobotany is extremely valuable for exploring and predicting the evolution of the habitability of the earth. In short, although it is generally recognized that coal was formed by plants, there has long been a lack of intuitive and clear evidence as to what plants formed it. The "Plant Pompeii" has given the answer, clearly showing humans the composition of the Permian coal-forming plant community and becoming a window to peek into the earth's ecology in the late Paleozoic.

Plant fossils and plant restorations found in the Wuda Permian vegetation fossil site in Inner Mongolia Autonomous Region ( Photo source: Xinhua News Agency )

03 How did the “ Plant Pompeii ” come into being?

300 million years ago, the entire North China region was still a large island immersed in the ocean. The Wuda region in Inner Mongolia, northwest my country, was still located near the equator and was a vibrant tropical rainforest. It was warm and humid, and was full of lycopods, knotweeds, gourd-leaved plants, ferns, primitive conifers, cycads, and other plants [2]. All of a sudden, an unprecedented volcanic eruption occurred, and thick volcanic ash drifted into the forest, instantly "sealing" all the trees. The once prosperous forest kingdom came to an end.

Plant fossils collected by the Haibowan District Museum in Wuhai City ( Photo source: Xinhua News Agency )

Hundreds of millions of years later, this 35 square kilometers of forest turned into a layer of volcanic tuff about 0.65 meters thick, buried in the present-day Wuda coal mining area in Inner Mongolia, superimposed with 20 layers of coal, silently telling the geological history and climate change over hundreds of millions of years [3]. It was not until the Wuda coal mining area was mined that geologists and paleontologists came here and hammered down, making this "Pompeii of Plants" see the light of day again and make it known to the world.

04 How to protect the “ Pompeii of Plants ”

As we all know, geological relics are rare and non-renewable geological heritages. Most of them are "unique" in the world. Once destroyed, they are priceless and cannot be replicated. Therefore, how to properly protect them is a big problem. Wuhai City, Inner Mongolia, where the "Plant Pompeii" is located, is known as the "Sea of ​​Black Gold". It is a city built because of mines and prospered because of coal. The famous Wuda Coal Mine is located in the southwest corner of Wuhai City. It is a huge mine pit with an area of ​​35 square kilometers and is shaped like a left ear. The total geological reserves of the Wuda Coal Mine are 630 million tons. Long-term open-pit mining has resulted in the original "Plant Pompeii" covering an area of ​​35 square kilometers, with less than 10% left today [3].

Partial landscape of Wuda coalfield in Wuhai City, Inner Mongolia ( Photo source: Xinhua News Agency )

Fossil protection is a world-class problem, especially when faced with the choice between fossil energy and fossil resources . Fortunately, with the concern of the local government and the joint efforts of scientists, an agreement on the joint protection of the "Pompeii of Plants" has been signed. In the future, a "Pompeii of Plants" museum and geological park will be built, and this rare Permian vegetation fossil group will remain in the world forever, giving full play to its greater value in plant taxonomy, paleoecology and geological research.

Author: Liu Hanbin, Senior Engineer, Shanxi Coal Geology Bureau

Produced by: Science Popularization China

References:

[1] Ni Sijie. Three treasure sites in my country are included in the list of global geological heritage sites [N]. China Science Daily, 2024-09-03.

[2] Wang Jun, Wan Mingli, Zhou Weiming. "Plant Pompeii": A rare window into coal-forming vegetation in the late Paleozoic [C] Annual Meeting of the Paleobotany Branch of the Chinese Paleontological Society and the Jiangsu Paleontological Society in 2021, Proceedings of the Annual Meeting of the Paleobotany Branch of the Chinese Paleontological Society and the Jiangsu Paleontological Society in 2021.

[3] Zhang Ye; Zhao Yingshu; Teng Jipu; Lin Lijun. How to protect the "plant Pompeii" under the coal seam [N] Science and Technology Daily, 2024-01-05. Page 05: Deep Eyes.