2020-07-21

The western part of Shijiazhuang was once an underwater world 2 billion years ago! The discovery of paleontological relics and stromatolite reef groups 2 billion years ago in Jingxing

By yqqlm yqqlm

Ma Baojun, a professor at Hebei University of Geosciences, and his team have recently discovered 2 billion in Shijiazhuang, a thousand-year-old county in Jingxing County The ancient biological relics layer before the year, and the stromatolite reef group. The discovery of these two relics can serve as a window for geologists to further study the Precambrian depositional environment and early paleontology.

The strata they studied belonged to the Zhaojiazhuang Formation of the Mesoproterozoic Great Wall System (geological academic name). This group can be divided into 4 sections, including coarse clastic rock layers, interbedded sandstone and shale, shale layers and stromatolite algal reef layers. The rock types are abundant, the stratum sedimentary characteristics are obvious, and it has an obvious indication of the ancient marine sedimentary environment. The discovery and related research of Ma Baojun and his team were published in the national geological core journal—Journal of Southwest Petroleum University Natural Science Edition.

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[Discover]

The stromatolite reef group and the paleontological relic layer appeared 2 billion years ago

Hebei University of Geosciences, where Ma Baojun taught, is the Ministry of Natural Resources, Hebei Province The People’s Government jointly established the university, which was one of the five universities directly under the former Ministry of Geology. During his tenure as a teacher in the College of Resources, Hebei University of Geosciences, he went deep into the field to conduct geological surveys and research on geological structures.

Ma Baojun said that their newly studied area is located in the southern section of the Taihang Mountains, in the town of Siyu Town, Jingxing County, southwest of the provincial capital Shijiazhuang City, and tectonically located in the north-central Taihang Bay at the southwestern end of the Yanliao rift trough, which is far from the provincial capital Shijiazhuang. The urban area is 80 kilometers away. In the process of geological survey, it was discovered that the paleontological relics and stromatolite reefs of 2 billion years ago were completely exposed on the ground, and the exposed sections were relatively intact. Some geologists have discovered similar paleontological relics before, but they have not conducted in-depth and comprehensive research. The stromatolite reef group found in Ceyu Town is the earliest in the Mesoproterozoic period in China. Its research value is The ornamental value, ecological value and social value are extremely high.

[Site]

2 billion years of earth evolution history hidden in ancient microbial holes

On July 18, the reporter drove with Ma Baojun and his party to Ceyu Village, Ceyu Town, Jingxing County. The traffic was smooth all the way, and the air was exceptionally fresh after the rain.

Ceyu Village is surrounded by mountains. The spring water in Yangpogou to the west of the village is very clear. On the east bank of Yangpogou, there is a reddish-brown layered rock that is particularly dazzling.

“There are many stories in this rock.” Ma Baojun couldn’t wait to lead everyone to their findings. I saw the reddish-brown rocks in a thin layered shape, more than 20 meters wide, about 3 meters high, and several hundred meters long. There are different regular holes on the plane and side of the rock, and the holes with a size of about 3 cm show white matter.

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The red-brown rocks are full of paleontological holes.

Ma Baojun said that this is a typical Zhaojiazhuang Formation ferrous quartz sandstone, which is composed of quartz, but the iron component that binds the quartz particles together is displayed in red. The gray-white fillings in the layer and the holes in the layer are dolomite particles, and the boundary with the outer red iron sandstone is obvious. Their research team called this biological sedimentary structure a burrow. According to the analysis of the stratigraphic age, it should be about 2 billion years ago. Existing data indicate that there were no macroscopic plants and animals on the earth at that time, so it is estimated that such holes should be formed by microbial adsorption, but other causes are not excluded. In short, the ancient microbial relics that you have seen are very large. The value of research.

“We used to study paleontology in a relatively single type.” Ma Baojun said, stromatolites have been discovered in many places before, but each stromatolite also has subtle differences. As a kind of paleontological algae fossils, It is the main way for everyone to study paleontology in the Precambrian period. In addition to stromatolites, the appearance of ancient microbial relics has allowed everyone to see another kind of habitat (academic name), which provides an additional material for researchers to study the evolution and growth of paleontology during that period.

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The whole stone is composed of this texture.

“Interlocking” reflects the evolution of the earthScenery

On the lone mountain north of Ceyu Village With lush green eyes, the slope of the mountain profile is 15 to 35 degrees. Standing at the foot of the mountain, you can see a piece of reddish-brown rock mentioned by Ma Baojun at the top of the mountain. Everyone began to go up the mountain and climbed several small-scale steep ridges, and came to a natural hill where the stromatolites were located, covering an area of ​​about 80 square meters, with a thin reddish-brown sand-like shape below, thought to be man-made mining. What remained, after observation, found that the stromatolites here are intact, and large patches of fine sand-like sand are caused by natural weathering.

The lush mountains are the only place where no grass grows. Ma Baojun said that under this piece of stromatolites are shale particles, which do not contain soil components. It is known as the”red desert”, and plants cannot grow.

The stromatolites here belong to algae adsorbing magnesium carbonate. This small ring is a kind of algae. During the growth process, it grows vertically when there is sunlight during the day, and grows horizontally when there is no sunlight at night. One layer grows a day, and every layer we see contains more layers, even with a microscope to see clearly, it must grow in shallow seas, and it must be of very clear water quality.

At the scene, the reporter saw that the biggest feature of stromatolites is that on the same stone, there are countless small circular textures, and the rules are different, such as circular, columnar, bifurcated, and wavy. Shaped, there are also flat layers. On the edge of another stone, a ring was found to be the size of a rice bowl. Compared with the countless small rings the size of a dollar coin next to it, it was particularly interesting.

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The textures on the stromatolites are ring-shaped and wave-like.

“It’s really rare to hear what you say.” A local villager heard that the stone here has such a long history and said happily that he has lived here since he was a child. I don’t know how to climb and play here. I didn’t expect that the stones here are fossils that have passed 2 billion years. The villager said that such a precious natural environment should be well protected and must not be destroyed.

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Traces of human prying.

[Interpretation]

West Shijiazhuang was an underwater world 2 billion years ago

Ma Baojun, a professor at the School of Resources of Hebei University of Geosciences, said that they have internship bases in the areas of Siyu and Zhanghewan. As an internship team leader, he often leads students here for geological mapping practice. Through detailed observation of the surrounding rock outcrops, a series of typical observation points have been determined. Among them, the Yangpogou paleontological relics and the Ceyugushan stromatolites are the most ornamental and academically valuable. These two types of paleontology The fossils were all born in the Zhaojiazhuang Formation of the Great Wall System. The Zhaojiazhuang Formation was named by Du Rulin, a professor at Hebei University of Geosciences, with a geological age of 2 billion years.

In the area where there are no stromatolites in the Zhaojiazhuang Formation, one of the observation points, the paleontological remains, is the paleontological remains fossils that appeared in Yangpogou of Ceyu Village. A large number of biological burrows have been found in the purple-red iron siltstone and thin quartz fine sandstone of the lower Zhaojiazhuang Formation exposed in Yinyuyangpogou. These burrows are 2 mm to 10 mm in diameter and 5 mm to 40 mm in length. It is circular on the plane, and the vertical plane is a cylinder with dense distribution.

The burrow is filled with off-white dolomitic silt, which can identify seaweed-like traces, needle traces, Rostolo van traces, worm traces, linear traces, cone traces, etc., which reflects a shallow water environment. Some people think that the formation of these burrows are traces of paleontological activities. Others think that there were no macroscopic organisms about 2 billion years ago. It should be the remnants of microbes. The specific microbes are different, but there is no doubt about these. Relics are of great significance to the study of the origin and evolution of organisms.

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Professor Ma Baojun is studying this piece of stromatolite that fell off.

At another observation point, the well-outcropped stromatolites on the hillside of Gushan Mountain in Ceyu Village can be divided into four sections. The stromatolites are mainly developed in the fourth section and are individual The reef is in the shape of a convex lens, sandwiched in red shale, 30 cm to 250 cm thick. The lateral distribution is unstable, and these reef layers have the same stromatolite type to form a complete reef system. The stromatolites are mainly primitive and simple layered columnar and low-level columnar shapes. Generally, the individual is small, with a diameter of 1 cm to 3 cm and a height of 5 cm to 10 cm. It has a gentle arc, a dark layer (rich algae) and a bright layer ( Poor algae) alternately appear, forming a diverse layered structure.

Compared with stromatolites in other regions, the Gushan stromatolites have their own characteristics in terms of age, type, shape, and scale, and have higher research value. Observed from a single reef body, its scale is small and the individual is also small, reflecting that the water environment at that time was a tidal flat environment affected by waves, but it was not suitable for the massive growth of cyanobacteria. Therefore, the Zhaojiazhuang Formation was found in the mountains around the fish. Outcropping, but stromatolites only appear in Gushan and distributed in the form of point reefs.

According to the classical theory of plate tectonics, the deformation history of the earth’s lithosphere can be divided into the initial plate, paleoplate and modern plate activity stages. The Mesoproterozoic where the Zhaojiazhuang Formation is located is at the beginning of the initial plate (the Colombian supercontinent). Cracking period. About 2 billion years ago, the Lvliang Movement caused the ancient North China land to merge and rupture, forming the Yanliao Taihang rift trough, with a scale between the sea and the ocean. The Zhaojiazhuang Formation belongs to shallow sea sediments. At the bottom, fossil remains of paleontology were first preserved, and stromatolite reefs were formed on the top, reflecting the colorful underwater world at that time.

[Evolution]

The two relics are North ChinaLandA typical evolution Representative

The majestic Taihang Mountains, dominated by Hebei, Henan and Shanxi Provinces, are important mountain ranges and geographical boundaries in eastern China. The tall Taihang Mountains were an ocean in ancient times. Ma Baojun introduced to reporters the ups and downs of the Taihang Mountains during the earth’s evolution.

The earth’s history is 4.6 billion years old, and the rock record time began 3.8 billion years ago. The ancient metamorphic rocks exposed in the Fuping and Zanhuang areas of the Taihang Mountains well record the earliest evolution of this area. 28 to 2 billion years ago was the period of large-scale patchwork. At that time, the ocean was distributed in a large area of ​​the earth. The ancient land core floating in the ocean grew and expanded rapidly, and merged together. This process was accompanied by a large number of volcanic activities. At the end of Mesoproterozoic, a unified North China land mass was formed.

About 540 million years ago, the Taihang Mountains fell again, and the entire North China block was in a stable environment of the surface sea, with seawater intruding from east to west. In the late Ordovician, under the north-south squeeze of the Paleo-Asian and Yangtze plates, the entire North China block was raised to the surface and suffered denudation. In the Late Carboniferous, the North China Block subsided once again, and neritic deposits were widely accepted, and it quickly transformed into marine-terrestrial and continental deposits. During this period, the North China landmass flourished and the environment was stable, making it the most favorable coal-forming period in China. The coal in the Jingxing mining area belongs to this layer, and the Zhaojiazhuang Formation at this time has been buried several kilometers below.

Since the beginning of the Mesozoic (195 million years) Yanshan Movement, the North China Plate was squeezed by the surrounding plates and the North China Plate was destroyed. The Taihang Mountain located in the central part of the Taihang Mountain as a whole appeared to be a fault block uplift. The rapid uplift caused the upper strata to suffer rapid Denudation made the Zhaojiazhuang group, which had been sleeping for 2 billion years, finally see the light of day. The two relics visited by this reporter are the crystallization of this ancient plate movement.

[Looking forward]

Come here to experience the feeling of”seeing each other and striding over a hundred million years in one step” p>

In terms of geological research, the growth form of stromatolites can help people judge the top and bottom of the rock formation. At the same time, the growth form and biological relics of stromatolites in the Zhaojiazhuang Formation provide a basis for the comparison of strata at different locations in this area, and also provide further It provides a basis for studying the ecological environment of the early earth.

In production and life, the rocks developed by stromatolites are highly ornamental. The ancient biological relics of Gushan stromatolites and Yangpogou in Ceyu Village add interest and connotation to the local green waters and mountains. The close contact between the mountain and billion-year-old fossils made everyone feel that they had crossed a billion years. Here, people can feel the vicissitudes of the vicissitudes of life, and experience the magic of”seeing each other forever, striding over a hundred million years in one step”.

Due to weathering and human activities, the fossil-bearing sandstone in Yangpogou has been partially excavated because of its ripples and mud cracks and other textures. It has also become a decorative stone for people’s buildings. Many small reefs such as Gushan stromatolites have collapsed in many places, and gravel with different patterns are scattered in the ravines. Both of these sites have suffered varying degrees of damage. If they are not protected in time, they may disappear after a few years.

After a comprehensive analysis, Ma Baojun and others suggested that the Yangpogou relic fossils, Gushan stromatolites, Gantao River ancient volcanic crater, and Dingpanzhai Zhangshiyan landforms in the Ceyu area should be planned and established. The cultural stele shall be constructed and protected as a tourist protection zone. Furthermore, it is possible to build higher-level geoparks in combination with surrounding geological scenic spots and tourist attractions to better realize”green water and green mountains are golden and silver mountains”, so that the lives of the surrounding villagers can move towards a well-off society as soon as possible.