Description of the formation of multi-shell dikes

Question 1: shell dike interpretation This entry is a disambiguation entry. 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 angle. Formed near the * * * line, it is a reliable sign of the ancient coast in landform. There are three famous shell dikes in the world, namely, Tianjin shell dike in China, Louisiana shell dike in the United States and Surinam shell dike in South America. Shell dike is an important research object of scientists for decades, which plays an important role in international research fields such as ocean, Quaternary geology, paleoclimate and paleoenvironment. This entry introduces the shell dikes in Tianjin, commonly known as "Clam Dike", "Shalingzi" and "Lingzilei". The ancients called it "North Hill"; Geomorphologists call it the "Dead Coast Embankment". Shell dike is a unique landform in Tianjin. It is a symbol of the coastline of the ancient Bohai Sea, and it is gradually accumulated by marine shellfish under the impetus of tides for thousands of years. The shell dike truly records the vicissitudes of Tianjin. The shell dike of Baishaling, a military grain town in Dongli District, is the historical footprint of land and sea changes. Shell breakwater is a kind of accumulation formed by washed biological shells in muddy and muddy coastal areas under the action of waves. Wave erosion increases the slope of the beach and coarsens the bottom material. Shells at the bottom are washed to the shore by seawater and accumulated near the * * * line, forming a berm after long-term action. When the coastal sediment source is sufficient and the beach sediment accumulation is vigorous, the shell dike stops developing. Many changes of erosion and siltation have left many shell dikes. It can be used as a symbol of ancient coastline migration. The history of coastal development can be restored by C 14 isotope dating. The formation of shell breakwater needs three conditions, namely silt and silt beach, relative seawater erosion background and rich shellfish sources. Historically, the Yellow River has been known as "good at silting, settling and moving". The Yellow River carries a large amount of fine-grained loess, which has migrated in the south and west coasts of Bohai Bay for a long time, creating the largest muddy coast in the world. When the Yellow River changes course and the estuary moves to other places, with the decrease of incoming sediment, the coast will no longer be silted up, the sea water will become clear, and a wide variety of marine mollusks will continue to multiply, providing sufficient shellfish sources. The most important thing is the tidal movement of the waves, mainly scouring. Shells were moved to the coast for accumulation, and with the accumulation of shells year by year, a unique seashell beach ridge coast was formed. Once the Yellow River is diverted and moved backward, shell dikes and mudflats with light seawater are not conducive to shell growth and stop. Outside the shell dike, sediment deposits into land, and the coastline extends forward. Shell dikes are far 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 stops, and silt and shell dikes alternate, forming a number of shell dikes parallel to the coastline on the south bank and west bank of Bohai Bay, which has also become the footprint of the Bohai Bay coastline extending to the Bohai Sea. Tianjin shell dike is located in Jinnan, Dagang and Tanggu in the east of Tianjin. It is a part of "Tianjin Ancient Coast and Wetland National Nature Reserve". The whole reserve is composed of shell dike, oyster beach and Qilihai wetland ecosystem, which is an extremely precious marine relic of ancient coastal changes. The research on shell dike, oyster beach and wetland in Tianjin has a history of several decades, and it has become an important place for marine, geology, geographical system and institutions to study coastal evolution, paleoclimate, wetland ecology and other disciplines. There are four shell dikes I, II, III and IV in Tianjin continental plain from the land to the sea, which are generally parallel to the modern coastline and distributed discontinuously in the form of ridges and hills, representing the position of the coast in four periods. /kloc-from 0/000 to 5,000 years ago, most areas of Tianjin Plain were submerged by transgression. After that, the sea level fell, rivers flooded and gradually became land. Shell dike is a relic left by this historical process, a unique coastal landform type in Tianjin coastal zone, and also a relic of the ancient coast of Bohai Bay, which reflects the change of coastline from land to sea. There are many kinds of shells on the dike, mostly molluscs living in intertidal zone or shallow sea. There are many kinds of shells on the embankment. These ancient oyster shells are about 30 cm long, which are very precious and rare, and now they are nowhere to be found. Tianjin shell dike is 0.5 ~ 5 meters high, tens to hundreds of meters wide and tens to hundreds of meters or hundreds of kilometers long. The top of its cross section is convex, and its wings are thinned into a point. Shell dikes and oyster reefs in Tianjin ancient coast and wetland nature reserve have the characteristics of large scale, good outcrop, strong continuity and clear sequence, which are most typical in the eastern coast of China and even rare in the western Pacific coast. The establishment of the reserve can protect these non-renewable geological landscapes, and provide extremely valuable natural data for the study of land and sea changes, paleogeography and paleoclimate in Tianjin and the eastern coastal areas of China. & gt

Question 2: Explain the relationship between the formation of shell dikes and coastal erosion and deposition environment. Shell dike is commonly known as "clam dike", "Shalingzi" and "Lingzilei". The ancients called it "North Hill"; Geomorphologists call it the "Dead Coast Embankment". Beidi is a symbol of ancient coastline, which is gradually accumulated by marine shellfish under the impetus of tides for thousands of years. Shell dike truly records the vicissitudes of coastal areas and is the historical footprint of land and sea changes.

The seashell is a kind of accumulation body formed by washed biological shellfish rushing to the shore in muddy and muddy coastal areas under the action of waves. Wave erosion increases the slope of the beach and coarsens the bottom material. Shells at the bottom are washed to the shore by seawater and accumulated near the * * * line, forming a berm after long-term action. When the coastal sediment source is sufficient and the beach sediment accumulation is vigorous, the shell dike stops developing. Many changes of erosion and siltation have left many shell dikes. It can be used as a symbol of ancient coastline migration. The history of coastal development can be restored by C 14 isotope dating.

The formation of shell breakwater needs three conditions, namely silt and silt beach, relative seawater erosion background and rich shellfish sources.

Question 3: The formation of Tianjin shell dike The old Tianjin people called the ancient shell dike clam dike, which was deposited by the ancient shell dike and can reflect the changes of coastal land and sea. Tianjin ancient shell dike is one of the three largest ancient shell dikes in the world, which is of great significance to understand the geological evolution of Tianjin. As a special type of coastal dike, the ancient shell dike must have sediment, slope and hydrodynamic conditions suitable for shellfish breeding and being brought to the shore by heavy waves. Therefore, according to the location of the ancient shell dike, we can determine the location of the ancient coast, and according to the relationship between the old and new shell dikes, we can also analyze the evolution process and dynamics of the coast. 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 angle. It is formed near the * * * line of the sea and is a reliable symbol of the ancient coast in landform. Holocene transgression occurred from 5000 to 10000 years ago, which flooded most of Tianjin plain. After that, the sea level fell, rivers flooded and gradually became land. Shell dike is a relic left by this historical process, and it is a unique coastal landform type in Tianjin coastal zone, reflecting the change of coastline from land to sea. The dam is 0.5 to 5 meters high, tens to hundreds of meters wide and tens, hundreds or more than 100 kilometers long. There are many kinds of shells on the dike, mostly molluscs living in intertidal zone or shallow sea. Shellfish like to grow and breed on the fine sand and muddy seabed with clear and transparent seawater and rich nutrients. Under the action of waves, especially rough waves, shells and sediment will accumulate under the condition of suitable slope, and shell dikes will be formed near the * * * line. The Yellow River is a world-famous river with high sediment concentration, which has changed its course seven times. The natural conditions along the coast of Tianjin are favorable for the formation and development of shell dikes when Shandong is in the sea. However, when moving northward to Tianjin to enter the sea, the turbidity of seawater increases and the slope gradient slows down, and its ecological environment and dynamic conditions are not conducive to the formation of shell dikes. Therefore, the shell dike not only represents the coastline position in a certain period, but also reflects the geographical environment at that time. Since 1970' s, the formation period of shell dike has been studied by using carbon isotope absolute dating method and archaeological method. It is generally believed that the third dike was formed in Shang Dynasty about 3500 years ago. The second dam was formed during the Warring States period about 2000 years ago. Diyi appeared in the late Yuan Dynasty and early Ming Dynasty. From this, we can understand the development process of coastal land formation in Tianjin area.

Question 4: Introduction to Shell Dike 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. Formed near the * * * line, it is a reliable sign of the ancient coast in landform. Shell dike is an important research object of scientists for decades, which plays an important role in international research fields such as ocean, Quaternary geology, paleoclimate and paleoenvironment. This entry introduces Tianjin shell dike.

Question 5: Where is the shell dike? Shell dike is located in Jinnan, Dagang and Tanggu in the east of Tianjin. Shell dike is an ancient marine relic more than 7000 years ago. It is a dike-like landform accumulation body composed of marine shells and their fragments and thin layers of fine sand, silt, peat and muddy clay under the action of tides and wind waves.

Question 6: Introduction of Tianjin shell dike Tianjin shell dike is one of the three famous ancient shell dikes in the world (the other two are Louisiana shell dike in the United States and Surinam shell dike in South America). It has been an important research object for scientists for decades, and occupies an important position in international research fields such as ocean, Quaternary geology, paleoclimate and paleoenvironment. It is a part of "Tianjin Ancient Coast and Wetland National Nature Reserve". The whole reserve is composed of shell dike, oyster beach and Qilihai wetland ecosystem, which is an extremely precious marine relic of ancient coastal changes. The research on shell dike, oyster beach and wetland in Tianjin has a history of several decades, and it has become an important place for marine, geology, geographical system and institutions to study coastal evolution, paleoclimate, wetland ecology and other disciplines.

Question 7: What is the reason for the formation of shell dikes? What is climate, weather and accumulation?

Question 8: Where is the shell dike in Tianjin? How's it going? Do you still have it? The so-called shell dike in Tianjin should be the shell dike wetland park. It's in the ecological park. You can walk north along the central street of TEDA. Pass by there. But to be honest, that's what the personal feeling there means. There are too many human factors, and the so-called sense of nature is lost. Or maybe we were born in Tanggu and used to seeing the real wild shellfish beach, but now we don't have it. Because all the cultivated land has been buried.

Question 9: The composition of Tianjin shell dike Tianjin ancient shell dike, together with the shell dikes in Louisiana, USA and Suriname, South America, is called the three largest ancient shell dikes in the world and plays an important role in the international Quaternary geological research. In the eastern part of Tianjin Plain, there are at least four shell dikes which are basically parallel to the modern coast. Shell dikes are distributed from north to south in Tianshuijing, Dasuzhuang and Shuyuanzi in Dagang District until Hebei Province. From 4500 to 4700 years ago, the shell dike was 22 ~ 27 kilometers away from the modern coast, and the shell species reflected the soft mud beach deposits in the inner bay of the coastal estuary. The nature reserve has established a sister reserve relationship with chesapeake bay National Estuary Research Reserve in the United States, and has been identified as a popular science education base in Tianjin.

Question 10: How to get to Binzhou Beiti? On June 25th, 2002, the people of Shandong Province approved the establishment of Wudi Shell Dike Island and Wetland System Provincial Nature Reserve, covering an area of 80,480 hectares. The main protection objects are the marine natural heritage and wetland biological system of Shell Ridge Beach. February, 2004 1 7, it was renamed Binzhou Shell Island and Wetland System Provincial Nature Reserve.

Wudi Shell Dike Island and Wetland System Provincial Nature Reserve is located in the north of Wudi County, Shandong Province, on the southwest bank of Bohai Sea, west to Zhang Weixin, east to Taoer River, north to shallow water -3m isobath, and south to Zhang Shanzi-Lishanzi-Xiabotou-Yangzhuangzi line. Geographical coordinates are: 37 54 ′ 30 ″ ~ 38 ″ north latitude19 ′10 ″ east longitude16 5438+07 45 ′ 08 ″ ~18 05 ′ 37 ″ The first row is located in the north of Chengkou Town, along the line of Zhangjiashanzi-Lijiashanzi-Xiabotou-Yangzhuangzi, with a length of nearly 40Km, a buried depth of 0.5- 1m and a shell thickness of 3-5m. It was formed in the middle of Holocene, about 5,000 years ago. The second column is located in the northeast of Chengkou Town, on the line of Dakouhe-Prince Fort-Zhaoshazi. It is nearly 22 kilometers long and consists of more than 40 shell islands. Island width 100-500m and shell thickness of 3-5m. It belongs to the * * * open type and was formed in the late Holocene, 2000-65438+. The two dikes are connected with Hebei shell dike, forming a large-scale shell dike ridge coast which is rare in the world and unique to China, and internationally known as Che Nier Coast.

Shell dike island 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, Wudi shell dike island has several unique features. First, the shellfish content is high. The shellfish content in Wudi ancient shell dike island is almost 100%, and there are few other impurities. Second, the old and new berms coexist. Wudi Island has not only ancient shell dikes 5000-2000 years ago, but also newly developed new shell dikes, and there is a tendency to form a third shell dike island. Other shell dikes at home and abroad are far away from the coast, so it is impossible to form new shell dikes. Thirdly, the typical shell beach wetland ecosystem is a valuable marine heritage in our province, the whole country and even the world, which has important scientific research significance and practical production value.

Wudi shell dike island and wetland system provincial nature reserve is the most complete shell dike in the world, and it is also the only one where old and new shell dikes coexist, with the protection of shell dike island and wetland ecosystem and rare and endangered birds as the main body. It is a transit station in the inland of Northeast Asia and the bird migration around the Western Pacific, a paradise for birds to overwinter, inhabit and breed, and an important base for studying environmental evolution and wetland types such as the change of the Yellow River, the change of coastline and the formation of shell dike island. It plays an extremely important role in the study of marine geology, biodiversity and wetland types in China.