Ancient shell dike

Ancient shell dike

Huanghua and Wudi ancient shell dykes are one of the three largest ancient shell dykes in the world. They are located in the coastal areas. Six ancient shell dykes are distributed from west to East, which are basically parallel to the coastline. The dykes are located in the southeast of Huanghua city and the northwest of Wudi, starting from shenzhuang in the north, passing Suncun in the South and extending 1.5km in the south.

introduce

Other ancient shell dykes

(1) Shenzhuang Dongsun village shell dike. The dike is located in the southeast of Huanghua City, starting from shenzhuang in the north, passing Suncun in the South and extending about 1.5km in the south.

(2) Miaozhuang a shell dike. The dike is about 3km southeast of Huanghua city.

(3) Xuguan -- Wudi terrace -- Shajingzi shell dike. The dike passes through the third branch of Zhongjie farm in SN direction. Xu guanduo, who starts from Jugezhuang in Tianjin in the north and ends in Huanghua in the south, is buried.

(4) Jilingpo liuhongbo shell dike. The dike is located on the west side of jilingpo, west of Guanjiapu, Huanghua. It is Sn trending and stretches for more than 3 km.

(6) Qikou zhaojiabao low tide shell dike. The dike is located at the low tide beach shell dike 2.2km from Gaotou village of Qikou to zhaojiapu.

The shell dike is a dike like landform accumulation body, which is composed of marine shells and their fragments and thin layers of fine sand, silt, peat and muddy clay, and is roughly parallel to the coast or has a small intersection angle. It is formed near the high tide line, which is a reliable sign of the ancient coast in geomorphology.

Historical age of ancient shell dyke

It is located in Huanghua City, Hebei Province, near Bohai Bay. On the vast tidal flat, there is an ancient shell dike extending for 76 kilometers to resist the turbulent tide. Thousands of years of tides have shaped this magical natural levee. If the coastal zone around the Bohai Sea is compared to a beautiful gold necklace, then the shell dike along the coast of Guxian County in northern Shandong is just like a brilliant pearl. Inlaid in the prominent position of the gold necklace, it is shining with dazzling light.

Located 60 kilometers north of Guxian City, Shandong Province, the ancient shell sand dike has a history of 5000 years. It stretches for 30 kilometers and grows at the rate of 100000 tons per year. It is a unique ancient Seashell beach ridge coast in China and rare in the world. He was promoted to a national nature reserve.

This is a bare shell dike connected by more than 40 shell islands, with a total area of 80480 hectares,. Its shell content is more than 90%, and the thickness of sand layer composed of complete shell, shell debris and shell sand is 2.5 m to 5 m. according to the determination of radiocarbon isotope, it was formed before 2500 to 1100 years. It is a rare marine natural relic in China and even in the world.

Composition of shell dike

The shell dike is a dike like landform accumulation body, which is composed of marine shells and their fragments and thin layers of fine sand, silt, peat and muddy clay, and is roughly parallel to the coast or has a small intersection angle. It is formed near the high tide line, which is a reliable sign of the ancient coast in geomorphology. During the transgression from 10000 to 5000 years ago, part of Cangzhou coastal plain was flooded. Later, the sea level fell back, the river alluvial, and gradually became land. Shell dyke is a relic of this historical process. It is a typical coastal geomorphic type in the coastal zone of Cangzhou. It is also a relic of the ancient coast of Bohai Bay, reflecting the shoreline changes from land to sea. There are many kinds of shells on the dyke, most of which are living species of benthic molluscs in intertidal zone or shallow sea. The levee is 0.5-5 meters high, tens to hundreds of meters wide, tens to hundreds of meters long or more than 100 kilometers long. The top of the cross section is convex and the wings are thinned to pinch out.

coast

The provincial nature reserve of gubeidi island and wetland system is located in the north of Guxian County, Shandong Province, on the southwest coast of Bohai Sea, reaching Zhangweixin River in the west, Taoer River in the East, shallow sea-3m isobath in the north and zhangshanzi lishanzi xiabotou yangzhuangzi in the south. The geographical coordinates are: 37 ° 54 ′ 30 ″～ 38 ° 19 ′ 10 ″ n, 117 ° 45 ′ 08 ″～ 118 ° 05 ′ 37 ″ E. Two rows of ancient shell dykes are distributed in the north of the territory. The first row is located in the north of Chengkou Town, in the line of zhangjiashanzi lijiashanzi xiabotou yangzhuangzi, with a length of nearly 40km, a buried depth of 0.5-1m, and a shell layer thickness of 3-5M. It was formed in the middle Holocene, about 5000 years ago; the second row is located in the northeast of Chengkou Town, in the line of DAKOUHE wangzibao zhaoshazi, with a length of nearly 22km, and consists of more than 40 shells The width of the island is 100-500m, and the thickness of the shell layer is 3-5M. It belongs to the open type. It was formed in the late Holocene, 2000-1500 years ago. There are two rows of ancient shell dikes in Hebei Province, extending for 76 kilometers, with shell reserves of 360 million tons. The two dikes are connected with the shell dikes in Hebei Province, forming a large-scale Shell Beach ridge coast, which is rare in the world and unique in China. It is internationally known as chenier coast.

There are three conditions for the formation of the beach ridge coast, namely, silt bank, relative seawater erosion background and abundant shell material source.

Historically, the Yellow River is famous for its "good silting, resolution and migration". It carries a large amount of fine-grained loess and migrates in the South and west coast of Bohai Bay repeatedly for a long time, shaping the largest muddy coast in the world. When the Yellow River changes its course and the estuary moves to other places, with the decrease of the amount of sediment, the coast will no longer be silted up and the sea water will become clear. A wide variety of marine molluscs will continue to breed and live, providing an adequate source of shells. The most important thing is the tidal movement of waves, which is dominated by erosion and moves shells to the coast for accumulation. With the accumulation of shells year by year, the unique beach ridge coast of shells is formed. Once the Yellow River changes its course and moves back, the shell dyke and the muddy bank with light sea water will stop the growth of shells. Outside the shell dike, the sediment deposited into land, and the coastline extended forward. The shell dike was far away from the coast, either abandoned on land or buried underground. Therefore, due to the back and forth migration of the Yellow River, the coastline stops and goes, the silt and the shell dike alternate, forming a number of shell dikes parallel to the coastline on the South and west coast of the Bohai Bay, which has become the footprints of the extension of the Bohai Bay coastline to the Bohai Sea.

environmental protection

The provincial nature reserve of ancient shell dyke and wetland system is the most complete and the only one in the world where new and old shell dykes coexist and the main body is to protect shell dyke Island, wetland ecosystem and rare and endangered birds. It is a transfer station for birds to migrate in Northeast Asia inland and around the Western Pacific, and a paradise for birds to overwinter, inhabit and reproduce. It is also an important base for studying the environmental evolution and wetland types such as the changes of the Yellow River, the coastline, the formation of shell islands and so on. It plays an important role in the research of marine geology, biodiversity and wetland types in China.

The ancient dyke has attracted numerous visitors and archaeologists. They stroll along the beach, pick up seashells and ride on the beach to enjoy the rewards of nature.

economic value

Ancient shell dike is a unique geological landform formed under specific geological conditions and geographical environment. Compared with the same type of shell dike at home and abroad, ancient shell dike island has several unique features. The first is the high content of shell material, the content of shell material of ancient shell dike island is almost 100% whether it is buried deep underground or exposed on the surface, and there are few other impurities; the second is the coexistence of new and old shell dike, the ancient shell dike island not only has the ancient shell dike 5000-2000 years ago, but also has the new developed new shell dike, and has the trend of forming the third shell dike island The other shell dykes are far away from the coast, so there is no possibility of forming a new shell dyke; third, the typical shell beach wetland ecosystem is a precious marine heritage in China and even in the world, which has important scientific research significance and practical production value. It has important scientific research and economic value for studying the location of the ancient coastline and inferring the evolution history of the coastal environment. Such a large gubeidi was only found in the United States and South America.

With a history of 5000 years and a length of 30 kilometers, the ancient shell dyke is a unique ancient shell beach ridge coast in China and rare in the world. It is also known as the world's three largest ancient shell dykes, together with Louisiana shell dykes and Suriname shell dykes. Facing the shell resources which still grow at the rate of 100000 tons per year, the ancients always adhered to the principle of moderate development and rational utilization, and developed the third new type of porcelain in the world - shell porcelain with shells as raw materials, which effectively protected the shell sand dike and made shell porcelain products become the pillar industry in the local area. The abundant shell resources of shell dyke provide important raw materials for shell carving processing, plastic rubber fillers, animal feed calcium, marine shell porcelain manufacturing, etc.

Present situation of ancient shell dike

In the past, due to the lack of understanding of the intrinsic scientific value of the shell dike resources, the lack of protection awareness and the lack of protection efforts, especially because the shell is a good natural feed additive and building materials, easy to exploit and low cost, the six ancient shell dikes in Huanghua have been damaged to varying degrees, and most of the above ground parts no longer exist. Up to 1995, only part of the embankment section between houtangbao and Zhangjuhe, about 1km long, still existed. According to scientific research, these ancient shell dikes were formed in the process of land formation on the west coast of Bohai Bay for more than 7000 years. Their development scale, time span and geological and paleoenvironmental information are rare in the world, and occupy a very important position in the international Quaternary geological research. It can provide a natural background for the study of paleoceanographic changes and environmental trends. In addition to scientific research, it also causes sea damage to storm surges

Chinese PinYin : Gu Bei Ke Di