Tianjin shell dike

--Tianjin shell dyke is one of the three famous ancient shell dykes in the world. There are dozens of shells in it, which are arranged according to the sequence and extend for tens of kilometers.

--Shell dike is a typical coastal geomorphic type in Tianjin Coastal Zone, and 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 the living species of benthic molluscs in the intertidal zone or shallow sea. The oyster shell is about 30 cm long, which is very rare.

--It's very shocking here. It's very chic. It's very interesting. The children are very happy.

Tianjin shell dike

Tianjin shell dyke is one of the three famous ancient shell dykes in the world (the other two are Louisiana shell dyke in the United States and Suriname shell dyke in South America). It is an important object of research by scientists for decades, and occupies an important position in the international research fields of marine, 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. It is an extremely precious marine heritage of ancient coast changes. Tianjin has a history of several decades in the study of shell dyke, oyster beach and wetland. It has become an important place for marine, geological and geographical systems and colleges to study coastal evolution, paleoclimate, wetland ecology and other disciplines.

geographic information

In Tianjin coastal area, marine shells are enriched to form dikes, which are locally called "clam dikes", "shalingzi" or shell dikes. There are dozens of shells in it, which are arranged according to the sequence and extend for tens of kilometers. Three shell dikes are found along the west coast of Bohai Bay. From east to west, the first dike starts from Gaoshangbao in the north and joins the second dike through caijiabao, Lvju River, gaoshaling, mapengkou and Qikou in the south. The elevation is 3-4 meters. Most of them are arc-shaped residual hills. The section from mapengkou to Qikou forms dikes continuously. The second dike is distributed in baishaling, Junliangcheng, Nigu, shanggulin, Qikou, jiajiabao and langtuozi, with an altitude of 3-4 meters. This dike is continuous and basically intact. The third dike passes through Xiaowangzhuang, ZhangGuiZhuang, Jugezhuang, Shajingzi, xiliuguanzhuang, etc., with an altitude of 4-5m. Part of the section is covered by late sediments and exposed near Jugezhuang, but the man-made damage is serious. There are more than 10 kinds of shell species and genera in the dike, such as Scapharca subcrenata, Meretrix meretrix, oncomelania tonkinensis, Oncomelania oblata, Sinonovacula cula, Oncomelania deltoidea, etc. Shell dike is a dike like deposit composed of shell and its debris mixed with sand.

formation

The old Tianjin people used to call the clam dike the ancient shell dike. It was formed by the deposition of ancient shells, which can reflect the changes of coastal land and sea. The ancient shell dike in Tianjin is one of the three 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 formation of ancient shell dike must have the conditions of sediment, slope and hydrodynamic force, which are suitable for shellfish breeding and brought to the shore by strong waves. Therefore, according to the location of the ancient shell dike, the location of the ancient coast can be determined, and according to the relationship between the new and old shell dike, the coastal evolution process and dynamics can also be analyzed.

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

The Holocene transgression which occurred 5000-10000 years ago flooded most of the Tianjin plain. Later, the sea level fell back, the river alluvial, and gradually became land. Shell dike is a relic of this historical process. It is a distinctive coastal geomorphic type of Tianjin Coastal Zone, reflecting the coastline change from land to sea. The levee is 0.5 to 5 meters high, tens to hundreds of meters wide, tens to hundreds of meters long or more than 100 kilometers long.

There are many kinds of shells on the dyke, most of which are living species of benthic molluscs in intertidal zone or shallow sea.

Shellfish like to grow and breed on the bottom of fine sand and silty sand with clear and transparent seawater and rich nutrition. Under the action of waves, especially surges, and under the condition of suitable bank slope, shells and sand will accumulate and form shell dike near the high tide line. The Yellow River is a world-famous river with large sediment content. It has changed its course seven times. When it swings to Shandong and enters the sea, the natural conditions in Tianjin coastal area are favorable for the formation and development of the shell dike. When it moves northward to Tianjin and enters the sea, the turbidity of the sea increases and the slope becomes gentle, so its ecological environment and dynamic conditions are not conducive to the formation of the shell dike. Therefore, the shell dike not only represents the location of the coastline in a certain period, but also reflects the geographical environment at that time. Since the 1970s, we have studied the formation period of shell dyke by using C isotope absolute dating method combined with archaeological methods. It is generally believed that the third dyke was formed about 3500 years ago in the Shang Dynasty, the second dyke was formed about 2000 years ago in the Warring States period, and the first dyke appeared in the late Yuan Dynasty and the early Ming Dynasty. Therefore, we can understand the development process of coastal land formation in Tianjin.

form

Tianjin ancient shell dyke, together with St. Louisiana shell dyke and Suriname shell dyke in South America, is one of the three largest ancient shell dykes in the world, and plays an important role in the international Quaternary geological research. In the east of Tianjin plain, there are at least four shell dikes which are basically parallel to the modern coast.

First course

The shell dike starts from xuntougu in Hangu District of Tianjin in the north, passes through TEDA, Lvju River, gaoshaling and Baishuitou, and ends at mapengkou in Dagang District from 200 to 1790 years ago. It is distributed near the extra high tide line in the eastern part of the marine accumulation plain, and its strike is roughly the same as that of the modern coast. It joins the second shell dike in Qikou and is dominated by shells and fragments. Shell species reflect the intertidal environment The research shows that there are people living on the dike in the late Ming and early Qing Dynasty;

The second way

From baishaling, Dongli District in the north to shanggulin, Dagang District in the south through dengcenzi and Banqiao farm in the south of Tianjin District, it is 1500-2600 years ago and 0-20 km away from the modern coast. It has a large scale and good continuity. It mainly consists of shells and fragments, reflecting the ecological environment of the lagoon estuary. The discovery of cultural relics of the Warring States period and the Han and Tang Dynasties on the dike indicates that it is an ancient coastline between the early Eastern Han Dynasty and the Tang Dynasty;

The third way

The shell dyke starts from huangcaotuo in Dongli District in the north, passes through Cuijia wharf, Jugezhuang, Zhongtang and xueweitai in the south. From 2800 to 3800 years ago, the shell dyke is distributed in the form of discontinuous ridges and hills in the direction of North-South or northwest southeast. The shell species reflect the lagoon coastal ecological environment. There are cultural relics of the Western Zhou Dynasty and the Warring States period on the dike;

The fourth way

Shell dykes are distributed from north to south in Tianshuijing, dasuzhuang, shuyuanzi of Dagang District and Hebei Province. From 4500 to 4700 years ago, shell dykes are 22 to 27 kilometers away from the modern coast. Shell species reflect the deposition of soft mudflat in the inner bay of coastal estuary.

The nature reserve has established a sister nature reserve relationship with chesbeck Bay National estuarine research reserve in the United States, and has been designated as the popular science education base in Tianjin.

significance

Tianjin shell levee is one of the three famous shell levees in the world (the other two are Louisiana shell levee in the United States and Suriname shell levee in South America). It is an important object for scientists to study for decades, and occupies an important position in the research field of marine, Quaternary geology, paleoclimate and Paleoenvironment in the world.

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. It is an extremely precious marine heritage of ancient coast changes. Tianjin has a history of several decades in the study of shell dyke, oyster beach and wetland. It has become an important place for marine, geological and geographical systems and colleges to study coastal evolution, paleoclimate, wetland ecology and other disciplines.

Traffic information

Take the shuttle bus line to the builder's apartment, and walk 1.9 kilometers.

Address: Dagang District, Tianjin

Longitude: 117.56055

Latitude: 38.746523

Tour time: 1 hour

Traffic information: it is located in Dagang District and can be reached by public transport

Take the shuttle bus line to the builder's apartment, and walk 1.9 kilometers.

Ticket information: Free

Opening hours: all day

Chinese PinYin : Tian Jin Bei Ke Di