The southern coast of Laizhou Bay, Bohai Sea, is one of the areas in China most seriously impacted by seawater intrusion. Based on the sources of intruding waterbodies, seawater intrusion can be divided into two types...The southern coast of Laizhou Bay, Bohai Sea, is one of the areas in China most seriously impacted by seawater intrusion. Based on the sources of intruding waterbodies, seawater intrusion can be divided into two types: intrusion of saline water derived from modern seawater, and intrusion of subsurface brine and saline water derived from paleo seawater in shallow Quaternary sediments. There are some distinct differences in their formation, mechanism and damage. The subsurface brine intrusion is a special type, which can cause very serious disaster. The coastal landform and the Quaternary hydrogeological environment are predominant factors in the classification of seawater intrusion types. Various coastal environments in different coastal sections result in three types of intrusion: seawater intrusion, saline groundwater intrusion, and mixed seawater and saline water intrusion, in the southern coast of Laizhou Bay, which can be divided into four areas: the seawater intrusion area in the northern Laizhou City coast, the mixed seawater and saline groundwater intrusion area in the Baisha River Jiaolai River mouth plain area, the mixed seawater and saline groundwater intrusion area in the Weihe River mouth plain area northern Changyi county coast, and the saline groundwater intrusion area in the northern Shouguang plains.展开更多
Analysis of 13 spore-pollen assemblage zones reflecting environmental changes since the later middle Pleistocene showed the succession of paleovegetation and the paleogeographic changes in the Bohai Basin and circumja...Analysis of 13 spore-pollen assemblage zones reflecting environmental changes since the later middle Pleistocene showed the succession of paleovegetation and the paleogeographic changes in the Bohai Basin and circumjacent area. Paleoclimatic variations here can obviously be divided into 5 cold and 5 warm periods : 2 cold and 1 warm periods in 200 ,000-100, 000 a B . P. (late middle Pleistocene ) 3 cold and 3 warm periods in 100 , 000-12 , 000 a B. P. (late Pleistocene), and 1 warm period since 12 ,000 a B. P. Late Pleistocene climate tended to become colder and colder. The coldest period was in the later stage of late Pleistocene, when the study area was a periglacial zone. The mean annual temperature then was about 10℃ lower than it is now. In the middle stage of late Pleistocene, climate became warm ; the mean annual temperature then was about 3 - 4℃ higher than it is now.By applying principles of climatic stratigraphy, the authors deduced through spore-pollen analysis , that the boundary between展开更多
Based on the authors’1986 to 1994 sporo-pollen assemblage analysis in the southern Yellow Sea area, data from 3 main cores were studied in combination with 14C, palaeomagnetic and thermoluminescence data. The evoluti...Based on the authors’1986 to 1994 sporo-pollen assemblage analysis in the southern Yellow Sea area, data from 3 main cores were studied in combination with 14C, palaeomagnetic and thermoluminescence data. The evolution of the paleoclimate environments in the southern Yellow Sea since 15ka B.P. was revealed that, in deglaciation of the last glacial period, the climate of late glaciation transformed into that of postglaciation, accompanied by a series of violent climate fluctuations. These evolution events happened in a global climate background and related to the geographic changes in eastern China. We distinguished three short-term cooling events and two warming events. Among them, the sporo-pollen assemblage of subzone A 1 showed some cold climate features indicating that a cooling event occurred at about 15-14ka. B.P. in early deglaciation. This subzone corresponds to the Oldest Dryas. In subzone A 3, many drought-enduring herbal pollens and some few pollens of cold-resistant Picea, Abies, etc. were found, which indicated that a cooling event, with cold and arid climate, occurred at about 12-11ka. B.P. in late deglaciation. This subzone corresponds to the Younger Dryas. The sporo-pollen assemblage of zone B showed warm and arid climate features in postglaciation. Although the assemblage of subzone B 2 indicated a cold and arid climate environment, the development of flora in subzone B 2 climate was less cold than that in A 3. Subzone B 2 indicated a cooling event which occurred at about 9ka B.P. in early Holocene. Subzone A 2, with some distinct differences from subzone A 1 and A 3, indicated a warming event which occurred at 14-13ka. B.P. and should correspond to a warming fluctuation. The sporo-pollen assemblage of zone C showed features of warm-moist flora and climate, and indicated a warming event which universally occurred along the coast of eastern China at 8-3ka B.P. in middle Holocene, and its duration was longer than that of any climate events mentioned above. This period was climatic optimum and belonged to an altithermal period in postglaciation.展开更多
Relevant geological, geographical, archaeological data were collected to study the characteristics of middle Holocene warm period and sea level high on North China coast. Middle Holocene climate and sea level change o...Relevant geological, geographical, archaeological data were collected to study the characteristics of middle Holocene warm period and sea level high on North China coast. Middle Holocene climate and sea level change on North China coast were correlated to warm marine environment events in about 8–3 ka B.P. The sea level in about 8 ka B.P. was higher than present mean sea level, then fluctuated for 5 000 years and after that it became even in 3 ka B.P. The highest sea level occurred in about 6–5 ka B.P.; the maximum was about 2–3 m and minimum was about 1–2 m.展开更多
Quaternary underground brine in the littoral plain region of the Bohai coast is new type littoral facies evaporation ore deposit in liquid state . This model of " littorally- forming brine " is based on stud...Quaternary underground brine in the littoral plain region of the Bohai coast is new type littoral facies evaporation ore deposit in liquid state . This model of " littorally- forming brine " is based on study of the distribution, depositional environment, forming / storing process, and genesis of underground brine in the coast of Laizhou Bay . Essential conditions for genesis of brine are arid and semiarid climate , abundant sources of ancient seawater, and geological and geomorphological environment of wide tidal beach along a coast. The process of underground brine genesis may be : seawater/tidal beach-evaporation and concentration-seeping and accumulation- brine/tidal beach - burial (evolution of the sea- land )- underground brine .Underground brine is characterized by high content of chemical elements, shallow burial depth and easy exploitation . The process of extracting salt from underground brine present in the tidal flat is incomparably superior to that of producing salt from seawater, and has展开更多
The discovery of useful brine resources in the embayed coastal zone of Qingdao is an important achievement in research on potential underground brine resources stored in Quatemary littoral facies in the North China co...The discovery of useful brine resources in the embayed coastal zone of Qingdao is an important achievement in research on potential underground brine resources stored in Quatemary littoral facies in the North China coast. The Holocene transgression in this area provided the ancient seawater sources for forming brine. In spite of the unfarorable geological conditions (narrow littoral plain. shallow and thin Quatemary sedimentary strata) Qingdao’s embayed coast has deposition basins with bay-in-bay and weir dam ideal for gathering brine. The geologic structure of the littoral Quatemary deposition basin and hydrologic condition(deficient runoff) comprise favorable environment for the formation and abundance of underground brine.The embayed coast geomorphy controls the distribution of brine in patches that form small mineral zones in some parts. The brine aquifer whiment series formed under Quatemary littoral plain sedimentary and hydrogeologic environment are usually single phreatic ones. Part of the thick deposit areas consists of phreatic and poorly confined aquifers. Near the river mouth, there can someimes be brine aquifers interbeded with saline water ones. The basement of the brine ore deposits is comprised of Mesozoic rock formations. Underground brine is scattered almost all over the littoral plain and only in the larger plain’s area is the narrow saline water belt distributed beyond the brine zone. The structural features of the brine aquifer sediment series along the Jiaozhou Bay Coast are typical of those in the North China coast. We name it"Jiaozhou Bay Type" Its features are different from those of other brine aquifer sediment series such as "Laizhou Bay Type" and"Bohai Bay Type" in the littoral plain of the Bohai Sea.展开更多
文摘The southern coast of Laizhou Bay, Bohai Sea, is one of the areas in China most seriously impacted by seawater intrusion. Based on the sources of intruding waterbodies, seawater intrusion can be divided into two types: intrusion of saline water derived from modern seawater, and intrusion of subsurface brine and saline water derived from paleo seawater in shallow Quaternary sediments. There are some distinct differences in their formation, mechanism and damage. The subsurface brine intrusion is a special type, which can cause very serious disaster. The coastal landform and the Quaternary hydrogeological environment are predominant factors in the classification of seawater intrusion types. Various coastal environments in different coastal sections result in three types of intrusion: seawater intrusion, saline groundwater intrusion, and mixed seawater and saline water intrusion, in the southern coast of Laizhou Bay, which can be divided into four areas: the seawater intrusion area in the northern Laizhou City coast, the mixed seawater and saline groundwater intrusion area in the Baisha River Jiaolai River mouth plain area, the mixed seawater and saline groundwater intrusion area in the Weihe River mouth plain area northern Changyi county coast, and the saline groundwater intrusion area in the northern Shouguang plains.
文摘Analysis of 13 spore-pollen assemblage zones reflecting environmental changes since the later middle Pleistocene showed the succession of paleovegetation and the paleogeographic changes in the Bohai Basin and circumjacent area. Paleoclimatic variations here can obviously be divided into 5 cold and 5 warm periods : 2 cold and 1 warm periods in 200 ,000-100, 000 a B . P. (late middle Pleistocene ) 3 cold and 3 warm periods in 100 , 000-12 , 000 a B. P. (late Pleistocene), and 1 warm period since 12 ,000 a B. P. Late Pleistocene climate tended to become colder and colder. The coldest period was in the later stage of late Pleistocene, when the study area was a periglacial zone. The mean annual temperature then was about 10℃ lower than it is now. In the middle stage of late Pleistocene, climate became warm ; the mean annual temperature then was about 3 - 4℃ higher than it is now.By applying principles of climatic stratigraphy, the authors deduced through spore-pollen analysis , that the boundary between
文摘Based on the authors’1986 to 1994 sporo-pollen assemblage analysis in the southern Yellow Sea area, data from 3 main cores were studied in combination with 14C, palaeomagnetic and thermoluminescence data. The evolution of the paleoclimate environments in the southern Yellow Sea since 15ka B.P. was revealed that, in deglaciation of the last glacial period, the climate of late glaciation transformed into that of postglaciation, accompanied by a series of violent climate fluctuations. These evolution events happened in a global climate background and related to the geographic changes in eastern China. We distinguished three short-term cooling events and two warming events. Among them, the sporo-pollen assemblage of subzone A 1 showed some cold climate features indicating that a cooling event occurred at about 15-14ka. B.P. in early deglaciation. This subzone corresponds to the Oldest Dryas. In subzone A 3, many drought-enduring herbal pollens and some few pollens of cold-resistant Picea, Abies, etc. were found, which indicated that a cooling event, with cold and arid climate, occurred at about 12-11ka. B.P. in late deglaciation. This subzone corresponds to the Younger Dryas. The sporo-pollen assemblage of zone B showed warm and arid climate features in postglaciation. Although the assemblage of subzone B 2 indicated a cold and arid climate environment, the development of flora in subzone B 2 climate was less cold than that in A 3. Subzone B 2 indicated a cooling event which occurred at about 9ka B.P. in early Holocene. Subzone A 2, with some distinct differences from subzone A 1 and A 3, indicated a warming event which occurred at 14-13ka. B.P. and should correspond to a warming fluctuation. The sporo-pollen assemblage of zone C showed features of warm-moist flora and climate, and indicated a warming event which universally occurred along the coast of eastern China at 8-3ka B.P. in middle Holocene, and its duration was longer than that of any climate events mentioned above. This period was climatic optimum and belonged to an altithermal period in postglaciation.
文摘Relevant geological, geographical, archaeological data were collected to study the characteristics of middle Holocene warm period and sea level high on North China coast. Middle Holocene climate and sea level change on North China coast were correlated to warm marine environment events in about 8–3 ka B.P. The sea level in about 8 ka B.P. was higher than present mean sea level, then fluctuated for 5 000 years and after that it became even in 3 ka B.P. The highest sea level occurred in about 6–5 ka B.P.; the maximum was about 2–3 m and minimum was about 1–2 m.
基金Project Supported by the National Natural Science Foundation of China
文摘Quaternary underground brine in the littoral plain region of the Bohai coast is new type littoral facies evaporation ore deposit in liquid state . This model of " littorally- forming brine " is based on study of the distribution, depositional environment, forming / storing process, and genesis of underground brine in the coast of Laizhou Bay . Essential conditions for genesis of brine are arid and semiarid climate , abundant sources of ancient seawater, and geological and geomorphological environment of wide tidal beach along a coast. The process of underground brine genesis may be : seawater/tidal beach-evaporation and concentration-seeping and accumulation- brine/tidal beach - burial (evolution of the sea- land )- underground brine .Underground brine is characterized by high content of chemical elements, shallow burial depth and easy exploitation . The process of extracting salt from underground brine present in the tidal flat is incomparably superior to that of producing salt from seawater, and has
文摘The discovery of useful brine resources in the embayed coastal zone of Qingdao is an important achievement in research on potential underground brine resources stored in Quatemary littoral facies in the North China coast. The Holocene transgression in this area provided the ancient seawater sources for forming brine. In spite of the unfarorable geological conditions (narrow littoral plain. shallow and thin Quatemary sedimentary strata) Qingdao’s embayed coast has deposition basins with bay-in-bay and weir dam ideal for gathering brine. The geologic structure of the littoral Quatemary deposition basin and hydrologic condition(deficient runoff) comprise favorable environment for the formation and abundance of underground brine.The embayed coast geomorphy controls the distribution of brine in patches that form small mineral zones in some parts. The brine aquifer whiment series formed under Quatemary littoral plain sedimentary and hydrogeologic environment are usually single phreatic ones. Part of the thick deposit areas consists of phreatic and poorly confined aquifers. Near the river mouth, there can someimes be brine aquifers interbeded with saline water ones. The basement of the brine ore deposits is comprised of Mesozoic rock formations. Underground brine is scattered almost all over the littoral plain and only in the larger plain’s area is the narrow saline water belt distributed beyond the brine zone. The structural features of the brine aquifer sediment series along the Jiaozhou Bay Coast are typical of those in the North China coast. We name it"Jiaozhou Bay Type" Its features are different from those of other brine aquifer sediment series such as "Laizhou Bay Type" and"Bohai Bay Type" in the littoral plain of the Bohai Sea.
