Yanqing Dinosaur Big Footprint

The Yanqing Dinosaur Footprint Fossil Conservation will complete the main project today. This is the first large-scale conservation since the discovery of the dinosaur footprint fossils in 2011. Through conservation, some previously uncertain "big footprints" were confirmed. The number of dinosaur "big footprints" increased from more than 170 to 185, the footprint fossils were also stronger, and some "illusions" became clearly visible.

"Big footprints" are only a few millimeters at the very shallow and easily weathered

Yanqing World Geopark is located in the northwest of Beijing with a total area of 620.38 square kilometers. A total of six dinosaur footprint fossils were found in the park, with the largest number of points on the 1st and more than 170 fossil footprints. This round of large-scale conservation is carried out around the 1st point.

These dinosaur footprint fossils have been around 150 million years ago. They are the only dinosaur fossil record in the world's metropolitan area, and the first time in Beijing that dinosaurs have survived. Preliminary studies have shown that the dinosaurs that left the dinosaur footprint can be attributed to sauropods, small and medium sauropods, large and small mammals and small birds.

Due to the natural environment of Yanqing, dinosaur footprint fossils on rocks are easily weathered and eroded. Since 2011, Yanqing District has taken a series of protective measures for these footprint fossils, such as rerouting part of the section of the Qiji Road where it is located to avoid human factors destroying fossils. Every winter, blankets are used to protect the slopes of the mountain where the footprints are located to reduce the negative impact of the cold weather.

However, protection can only maintain the status quo, and it is necessary to carry out professional conservation in order to further remove the destructive factors of fossils and prolong its "life". According to Zeng Guangge, chief of the Department of Geological Remains Protection and Construction of the Yanqing World Geopark Management Office in Beijing, these dinosaur footprints are as deep as two or three centimeters, and the shallowest is only a few millimeters. If not kept in time, there will be weathered after a long time. risk.

Dinosaur "big footprint" increased to 185

To this end, the Geopark invited the conservation experts from the Lesvos World Geopark in Greece and the team of Professor Zhang Jianping from the China University of Geosciences (Beijing). “The Greek Lesvos World Geopark and the Yanqing World Geopark have similar geological heritage, and the museum has rich experience in fossil conservation and has the qualification for this technology.” Zeng Guangge said that their core Techniques, including chemical reagents, are not currently available in China.

In late October last year, the park launched the first phase of experimental conservation of the dinosaur footprint fossils. Experts from Greece used three days to experimentally protect the three dinosaur footprints and surrounding rocks. “Experts applied a special anti-weathering agent to the rock. After a winter monitoring and observation, the rock not only has no adverse reactions under the action of the reagent, but also has a dense and solidified effect.” Zeng Guangge said.

The second phase of conservation was launched in May this year. Experts conducted a wide range of experimental conservation on the 1st point of the dinosaur footprint. After a summer rainy season, the chemical reagents used to prevent the fossil surface weathering effect. This conservation is mainly to continue the experimental conservation work for the dinosaur footprint fossils at the top of the unfinished slope on the 1st point of the dinosaur footprint, and complete the winter conservation test. What is gratifying is that during the conservation process, the experts have confirmed a number of footprint fossils that were previously unambiguous due to ambiguity. "The total number of footprints at point 1 has now increased to 185."

Part of the "illusion" becomes visible to the naked eye

This round of experimental conservation, in addition to ensuring that the rock formation where the dinosaur footprint is located is not affected by rain and snow erosion and weathering, but also more clearly present the morphological characteristics of the dinosaur footprint and protect the most important core geological remains in the Yanqing World Geopark. "There are some 'illusions' that have not been processed before the top of the slope. It is some unclear footprints. It becomes very clear after this conservation. When the weather is good, the footprints after conservation are more reflective, standing. The bottom of the mountain can directly see the footprints above. This is the most intuitive effect.” Zeng Guangge said that this was completely invisible before conservation.

Next, the Yanqing World Geopark will continue the third phase of conservation work with the Greek Lesvos Wood Fossil Forest World Geopark to further protect the dinosaur footprint fossils at other points in the Yanqing World Geopark, and will also unearth new ones. Silicified wood for conservation.

on site

Chinese and foreign experts in the rain for the dinosaur footprint "injection on the medicine"

Wearing a safety helmet, wearing a white coat and wearing blue plastic gloves on his hands, the nurses look a lot like doctors in the hospital, and the work they are doing is precisely to "treat" the dinosaur footprint fossils. Some use a brush to clean the surface of the rock, and some use different thickness of the needle to give the dinosaur footprint "injection." The rainy time of the patter is slow and the outdoor temperature in Yanqing Mountain is less than 10 °C. The nose of a red man has been frozen.

There are three main steps for these “big footprints” to “review”: the nurses should first wash the footprints and surrounding rocks with alcohol and water to remove impurities. The hardness of the brush is moderate, too soft and some dust cannot be wiped out. Too hard to be afraid of damage to the footprints, sometimes just a little brush directly with a toothbrush.

After cleaning up, you should proceed to the next step - "injection on the medicine". "This is the most critical step. The chemical reagents and filling techniques used are brought by the Greek expert team." Zeng Guangge said that now All are experimental conservation, and how to "apply medicine" is also stressful. First look at the rock surface with or without cracks, and then further processing according to the size and state of the "wound". The "wound" is filled with cement sand, and the small one is glued with special glue. Then the needle is used to inject the reagent into the inside. "To ensure that the reagent is fully infiltrated, the rock can be reinforced." Finally, the experts brush the reagents on the footprint and the surrounding rock. These chemicals, in addition to the bonding and strengthening, can also resist external weathering. (Reporter Zhao Tingting Photography / Reporter Yuan Yi)

dialogue

It is recommended to cover the dinosaur footprint with a glass cover.

Conversation: Elias Valiacos, deputy director of the Lesvos Geopark Museum in Greece and head of conservation project

Beiqing Daily: What factors in the natural environment have the greatest damage to dinosaur footprint fossils?

Ilias Valiacos: Weathering and rain damage the fossils the most. Water, in particular, has the greatest damage to the remains of fossils in the wild. Water not only accelerates weathering, but also allows plants in the gap to grow. When the temperature is reduced, the water will turn into ice, which will also cause the cracks in the rock to expand and even cause the entire rock to collapse. In addition, the role of water droplets is not to be underestimated, so how to prevent water damage is very important. It is recommended to put a glass cover on the dinosaur footprint fossil to isolate the air and water for the best protection.

Beiqing Daily: In the future, there will be conservation of silicified wood. What is the difference between dinosaur footprint fossil conservation and silicified wood conservation?

Ulysses Valiacos: Through last year's sampling, we found that there is silicon in the dinosaur footprint, which means that it contains the same substance as the silicified wood. The difference between the two conservations is that silicified wood fragments and misplaced parts are more and need to be continuously spliced and handled. The dinosaur footprint is mainly on a slope, and it does not need to be moved in a large scale, just for conservation. However, the conservation of both is a continuous process, not completed at once.