Using unique technology, the Greek experts injected and applied a primer to the fossil footprints to increase their resistance to erosion. They also cleaned the fragmented rocks that had become weathered in previous years and tried to restore their original appearance.

Ilias Valiakos, leader of the Greek team, said, "We've had to glue some footprints together to make the surface very solid so that no pieces will be lost."

With winter approaching, the expert team accelerated the protection work to finish the project before snow falls.

"In addition to pouring rains, freezing will also have an obvious influence on the small cracks on the slope," said Valiakos, who is deputy director of the Natural History Museum of the Lesvos Petrified Forest. "Some plants that grew up between the cracks are not helpful to the protection of dinosaur tracks."

Yanqing UNESCO Global Geopark has an area of 620 square kilometers, with rocks there dating from 3.5 billion years to 150 million years ago.

In January 2012, the first cluster of dinosaur trace fossils from 150 million years ago was unearthed by Zhang, followed by more discoveries of dinosaur trace fossils in the same sandstone.