The ammonoid is right in the middle of the chert

CHONGQING (CQNEWS) -- Ammonoid, faulted cliffs, stone forests, flint… These geological relics located in Yungui Mountain Scenic Area in Yubei District are evidence of Chongqing’s transformation from ocean to land.

Recently, the 52nd World Earth Day Science Popularization Event, sponsored by Chongqing Municipal Bureau of Planning and Natural Resources and organized by the Sichuan Southeast Geological Brigade of Chongqing Geological Survey Bureau, was held at Yungui Mountain to introduce the geological changes of Chongqing to the public and popularize geological relics and knowledge.

Ammonoid, evidence of the transformation from ocean to land

Tang Yongyang, deputy director of the Geological Investigation Institute of Sichuan Southeast Geological Brigade of Chongqing Geological Survey Bureau, introduced that Mingyue Mountain is one of the four major mountains in the main urban area of Chongqing. It has a variety of geological phenomena, and the mountain ranges belong to one of the important branches of the famous Sichuan East Parallel Ridge Valley, with the overall back-sloping structure and the central part of the mountain range exposing the Changxing Formation strata, which can be traced back to the Permian period 250 million years ago. “During the Permian period 250 million years ago, Chongqing was then a vast ocean. In the subsequent 250 million years of history, Chongqing went through a process from the Yangzi Sea to the Bashu Lake and then to land.” And evidence of all these important geological changes can be found on Mingyue Mountain, said Tang Yongyang.

Yungui Mountain is located in Mingyue Mountain, named for it resembles a giant tortoise lying among the clouds. Standing on the ridge of the mountain, visitors may overlook the whole city of Changshou to the east and Yubei urban area to the west, and many geological relics have been found on the mountain.

“Children, see, what is here?” Sister Xiao'ai, a science popularizer, asked on the day of the event, pointing to a ammonoid on a chert rock.

“This is a fossil.” “This is a rock.” “This is conch.” …

While entering from the south gate of Yungui Mountain Scenic Area and following the main road all the way forward to Guanyin Pavilion, a huge piece of Permian Changxing Formation chert comes into view, and the ammonoid is right in the center of the chert.

“Ammonoid, named for the surface line pattern resembles a chrysanthemum, first appeared in the Early Devonian, developed rapidly in the Permian, flourished most in the Mesozoic, and then all became extinct at the end of the Cretaceous.” Sister Xiao'ai introduced. Ammonoids are found in shallow marine sedimentary strata and are symbiotic with many marine fossil organisms.

“More than 200 million years ago, it used to be the Yangzi Sea, and due to the mountain formation movement, the earth's crust rose and the bottom of the ocean became high mountains. As a result, the ammonoid, which lived on the bottom of the ocean, was presented on the ground rocks and became a strong evidence of ocean-land change,” said Sister Xiao'ai.

Rich in geological relics, with a view of 3,000 meters of cliffs

The geological relics that can be seen on Yungui Mountain are far more than ammonoids. Up the stone steps, a stone forest karst landscape comes into view, which is large in size relatively. Visitors can find ammonoids in the labyrinth of stone forest, observe the thousands of stone buds left behind by karst action, discover the beauty of nature and understand the magic of natural power.

Karst landform is a phenomenon formed by the chemical dissolution and mechanical action of groundwater and surface water on soluble rocks. On the surface, karst gullies and rock buds, funnels, karst depressions, peaks, and forests can be formed, while on the underground, karst caves, caverns, underground dark rivers and natural bridges can be formed.

At a viewing platform on the side, the 3,000-meter winding cliff face can be observed in good weather. “Here is the steep cliff formed by the reverse fault. The steep cliff is a fault surface, the older strata are on the steep cliff or above it, and the new strata are under the steep cliff. Under the squeezing stress, the older strata rise along the fault surface and the newer strata fall relatively, thus forming the fault cliff.” Sister Xiao'ai introduced to everyone.

“In addition, children, you can also observe flint in the rock forest, which is often referred to as fire stone.” Sister Xiao'ai said that flint is usually dark gray or black in color and irregular in shape, often protruding from the surface of the chert, adding some interest to the dull and unexceptional chert.

With the May Day holiday drawing near, you could navigate the Yungui Mountain Scenic Area if you want to visit there. After entering the scenic area from the south gate, you could walk around the scenic area to look for geological evidence of ocean and land changes, while enjoying the natural scenery, camping and sightseeing, etc.

In addition, the summit of Yungui Mountain is 1,083 meters above sea level, there is a certain temperature difference between the top and the bottom. In case of rain and fog, you may bring rain gear and clothes to protect yourself from wind and cold. (Translated by Wang Junli, Fathom Language Limited)