This paper first introduces procedures leading to the establishment of Late Permian-Middle Triassic sea level change curve of Yangtze platform. Bathymetric curves extracted from curve of habitat types are first trans...This paper first introduces procedures leading to the establishment of Late Permian-Middle Triassic sea level change curve of Yangtze platform. Bathymetric curves extracted from curve of habitat types are first transformed to sea level curves stage by stage. Comparison between curves of Yangtze and the world reveals that because the Late Permian marine sequences are lacking in most parts of the world, the Late Permian to Griesbachian curve of Yangtze may serve as an important reference for further revision of the world curve. The Early-Middle Triassic short-term changes of Yangtze are briefly concordant with those of Haq's world curve, whereas their long-term changes are discordant. The latter, however, is representative of the East Asian regions affected by the Indosinian orogeny. Basically the third cycles of Yangtze and the world are only pertly concordant, and even in concordant cases their concrete boundaries are not coincident. This indicater that sea level changes are not strictly synchronous over the world. It seems that the 1st and 2nd cycles (supercycles and megacycles) may be world-wide, but not the 3rd cycles.展开更多
In the present paper, the Holocene sea level changes and coastline shifts in Zhejiang, China are discussed, based on the ancient coastline evidence related with sea level changes and 21 14C dat-ings of shell, peat or ...In the present paper, the Holocene sea level changes and coastline shifts in Zhejiang, China are discussed, based on the ancient coastline evidence related with sea level changes and 21 14C dat-ings of shell, peat or mud and wood samples along the Zhejiang coast. The development of Zhejiang coastline during the Holocene period can be divided into four stages. A lot of data of historical period and modern times have shown that tracing coastline shifts back to its source, we have to consider tremendous effects of man's activities besides natural factors, such as elevation and subsidence of the earth crust, sea level changes, supply of sediment, and littoral hydrodynamics.展开更多
Mangroves,widely distributed along the coasts of tropical China,are influenced by Asia monsoon,relative sea level change and enhanced human activity.To predict the impacts of future climate change on mangrove ecosyste...Mangroves,widely distributed along the coasts of tropical China,are influenced by Asia monsoon,relative sea level change and enhanced human activity.To predict the impacts of future climate change on mangrove ecosystems,it can be understood by reconstructing past mangrove dynamics using proxies preserved in coastal sediments.In this study,we quantitatively partitioned buried organic matter(OM)sources,collected from a vulnerable mangrove swamp in the Qinzhou Bay of northwestern South China Sea,using a ternary end-member mixing model of δ^13C and C:N values.Mangrove-derived OM(MOM)contribution was used as a tracer for mangrove development since 2.34 cal ka BP.This information,together with paleoclimate records(i.e.,speleothem δ^18O values,sea level change,grain size parameters)and human activity,was used to divide mangrove development into three stages during the late Holocene:relative flourish(2.34-1.13 cal ka BP),relative degradation(1.13-0.15 cal ka BP)and further degradation(0.15-0 cal ka BP).Before 1.13 cal ka BP,mangroves flourished with a high MOM contribution((88.9±10.6)%),corresponding to stable and high sea level under a warm and humid climate.After 1.13 cal ka BP,rapid fall in relative sea level coupled with the strengthening of the Asian winter monsoon,resulted in mangrove degradation and MOM reduction((62.4±18.9)%).Compared with air temperature and precipitation,the relative sea level fall was the main controlling factor in mangrove development before entering the Anthropocene(the time of the Industrial Revolution).After^150 cal a BP,reclamation of mangrove swamps to shrimp ponds is the main factor causing mangrove degradation and MOM reduction.展开更多
In view of the huge ice cover of 24. 5× 106 km3 in Antarctica, which accounts for over 90 % by volume of the ice body on earth, the movement of Antarctic glaciers is a major control on global sea-level change and...In view of the huge ice cover of 24. 5× 106 km3 in Antarctica, which accounts for over 90 % by volume of the ice body on earth, the movement of Antarctic glaciers is a major control on global sea-level change and climatic fluctuation. As recorded in the Quaternary deposits in King George Island, West Antarctica, three rapid ablations can be recognized at 11000, 9000 and 6100 years ago and the global climate within the past 6000 years is characterized by small-amplitude warm-cold fluctuation. Intertidal deceits at the north bank of the Shenzhen Bay suggest a periodic variation in sea level in about every 670 years over the last 6000 years with low sea levels recorded in the periods of 5500 - 4900, 3900 - 3600, 2400 2200 and 1300 - 1200 years ago. Between these periods the sea level rised for about 80 cm onaverage. The modern warming climate in the last century corresponds with a rise of sea level atthe rate of 2 - 3 mm/a.展开更多
According to the latest International Chronostratigraphic Scheme (ICS, 2000), the Permian in the Middle Lower Yangtze region of South China can be divided into three series and nine stages relevant to the traditional...According to the latest International Chronostratigraphic Scheme (ICS, 2000), the Permian in the Middle Lower Yangtze region of South China can be divided into three series and nine stages relevant to the traditional six stages of South China. From Assellian to Changxingian of Permian, 44 Ma in age range, the strata are composed of 14 third order sequences, each of which is 3.14 Ma in average age range. There is one third order sequence of Zisongian, equivalent to middle and upper Chuanshan Formation or equal to Asselian and two thirds of Sakmarian. There are two third order sequences, corresponding to Liang shan Formation or Zhenjiang Formation and upper Chuanshan Formation, which are assigned to Longlingian, coinciding with Artinskian and one third of Sakmarian. In addition, three third order sequences, equal to Qixia Formation, are attributed to Chihsian, corresponding to Kubergandian and one third of Roadian. Four third order sequences, comprising Gufeng, Maokou, Yanqiao, Yinping and Wuxue formations, are assigned to Maokouan, equivalent to two thirds of Roadian, Wordian and Capitanian. Two third order sequences, equal to Longtan Formation or Wujiaping Formation, are included in Wuchiapingian. Other two third order sequences, corresponding to Changxing Formation or Dalong Formation, are assigned to Changhsingian. In brief, these above third order sequences can be incorporated into 4 sequences sets.展开更多
Coastal dune rocks in China are eolian sands cemented by calcium carbonate under subaerial conditions, widely distributing on the tropical and subtropical coasts of South China. Particular temperature and precipitatio...Coastal dune rocks in China are eolian sands cemented by calcium carbonate under subaerial conditions, widely distributing on the tropical and subtropical coasts of South China. Particular temperature and precipitation as well as local wave and landform conditions are required for the formation of the dune rocks. A correspondence was found between Holocene environmental changes and coastal dune rock development by comparing the features of the sea-level and climate changes in the Holocene period with the ages, scales, and cementation of the dune rocks on the South China coasts. The findings provide well grounded explanation for some problems unresolved in the past researches on the coastal dune rock in South China： （1） There were no dune rocks with ages older than 6000 years in South China because the dune rocks formed before 6000 a BP were covered by the sea water that rose in the later period; （2） the dune rocks with ages of around 3000 a BP were widely found in South China today because the coastal dunes were cumulated on a large scale at that time as a result of temperature falling after the end of Megathermal; （3） Medieval Warm Period was the main period for the eolian dunes to be cemented into the coastal dune rocks in South China; （4） lack of dune rocks of younger than 1000 a BP was accounted for by that the climate conditions in recent one thousand years were not suitable for the cementation.展开更多
Climate change and urbanization issues are the two key factors that make humans liable to be affected by disasters, which are overlapped in urban agglomeration. The five big urban agglomerations of China with strong e...Climate change and urbanization issues are the two key factors that make humans liable to be affected by disasters, which are overlapped in urban agglomeration. The five big urban agglomerations of China with strong economic power are the important engines for national economic and social development. However, being in the sea-land mutual interaction belts with a vast hazard-bearing body, they are affected by sea-land compound disasters, and are liable to suffer heavy disaster losses with climate change. It is suggested that government departments concerned should fully recognize the impact of climate change on coastal urban agglomerations, propose strategies as soon as possible, and integrate the impact of climate change and adaptation countermeasures into the various kinds of social-economic development plans for coastal urban regions.展开更多
Sedimentary environment and distribution of brachiopods during the Changhsingian in Xingwen, Si-chuan Province of the upper Yangtze region, are statistically analyzed. Changing regularity in diversity of brachiopod is...Sedimentary environment and distribution of brachiopods during the Changhsingian in Xingwen, Si-chuan Province of the upper Yangtze region, are statistically analyzed. Changing regularity in diversity of brachiopod is synthetically investigated based on qualitative and quantitative analysis of transgres-sion-regression cycles. The results show that the diversity of brachiopods in this region in the trans-gression (aggradation) sequence is higher than that in the regression (progradation) sequence. The brachiopods in this area began to diversify in the early Changhsingian. And the species diversity had four peak stages which are respectively in the middle Early Changhsingian, late Early Changhsingian, early Late Changhsingian and late Late Changhsingian. The species diversity reached its highest in the late Late Changhsingian but this is followed by a sharp decrease at the end-hanghsingian, indicating the mass extinction of most brachiopod species which were prosperous in the Late Paleozoic.展开更多
The lower reaches of the Minjiang River and its adjacent areas were among the most active prehistoric archaeological areas in Fujian Province.The accumulation types of Neolithic archaeological strata are roughly divid...The lower reaches of the Minjiang River and its adjacent areas were among the most active prehistoric archaeological areas in Fujian Province.The accumulation types of Neolithic archaeological strata are roughly divided into dune sites and dune/shell mound sites.The sites can also be roughly divided into estuarine,coastal,and sea-island sites based on their geomorphic features.The cultural development of these prehistoric sites is of great significance for understanding the migration and spread of Austronesian civilization.Based on luminescence dating of typical Neolithic sites on Haitan Island,their quartz-OSL(optically stimulated luminecesence)burial ages were determined.Synthesizing previously published results,the temporospatial distribution characteristics of the sea-island sites on Haitan Island are discussed,and the relationship between Neolithic human activities and regional geomorphic processes is analyzed.The results show that:(1)the spatial and temporal distribution of the Haitan Island Neolithic sites are closely related to small-scale geomorphic features and are controlled by mesoscale geomorphic processes.The sites were mainly distributed in the foothills of two high hills along an NNE-SSW trend.With an increase in altitude,the features were distributed as“single site(I)–superimposed site–single site(II)”and appear successively.Single type sites(I)mainly appeared at low sea level,whereas single type sites(II)mainly appeared at high sea level.Superimposed sites were not subject to sea level changes.The relative elevation of the superimposed sites in the study area indicates the optimal residential area for human activities in the region.The single site with an elevation lower than the optimal residential area was mainly restricted by the lowest residential area,whereas the single site at a higher elevation than the optimal residential area was mainly affected by livelihood patterns.(2)High sea level caused by the“backwater effect”in low latitude areas in the southern hemisphere,and coastal aeolian sand activity influenced by sea level fluctuations in the middle Holocene correspond well with human activities recorded in the cultural stratigraphy of sea-island type sites.The altitude of coastal aeolian sand accumulation can be used as an indirect index to estimate the age of coastal dunes.展开更多
Based on 22 sparse-distributed tide gauge records in the Northwest Pacific Ocean marginal sea, the process, characteristic and prediction of regional sea level change are discussed by the integration of the following ...Based on 22 sparse-distributed tide gauge records in the Northwest Pacific Ocean marginal sea, the process, characteristic and prediction of regional sea level change are discussed by the integration of the following methods. Firstly, the regularized EM algorithm （RegEM） and the Multi-taper Spectral Method （MTM） are adopted to interpret their multiscale fluctuation processes and their spatial-temporal variations. Secondly, the orderly cluster method is introduced to classify these tidal stations, and with the consideration of the space adjacent relation, we obtain five sub-regions （the coasts of Bohai Sea-northern Yellow Sea, Yellow Sea-East China Sea along Chinese coast, the East China Sea along Japanese coast, the southern East China Sea and the northwestern South China Sea）. Furthermore, the Mean Generation Function （MGF） is explored to predict the medium- and long-term trends of each tide station. Finally, the Principal Component Analysis （PCA） is employed to obtain regional-scale sea level change trends, sea level rise rates of the above five sub-regions from 2001 to 2030 are 1.23-1.27 mm/a, 3.30-3.34 mm/a, 2.72-2.76 mm/a, 1.43-1.47 mm/a and 1.13-1.15 mm/a respectively, and the whole region sea level rise rate is between 2.01 mm/a and 2.11 mm/a. The aim of our work is to conduct an integrated research on regional sea level change.展开更多
地质调查发现,山东半岛西北部的莱州湾滨海地区普遍发育黑土湖组滨海湖沼相、潟湖相沉积,其下伏末次盛冰期泛滥平原相沉积,上覆全新世中晚期海侵层。黑土湖组的分布受古地形和全新世海侵的影响,其形成时代为8.5—5.5 ka B.P.,即由现代...地质调查发现,山东半岛西北部的莱州湾滨海地区普遍发育黑土湖组滨海湖沼相、潟湖相沉积,其下伏末次盛冰期泛滥平原相沉积,上覆全新世中晚期海侵层。黑土湖组的分布受古地形和全新世海侵的影响,其形成时代为8.5—5.5 ka B.P.,即由现代海岸线附近因8.5 ka B.P.前后海面上升环境效应开始出现,向陆地方向逐渐过渡到最大海侵线附近的5.5—6.0 ka B.P.期间形成。该地层单元的穿时性指示了海侵向陆地方向的推进,以及大约自5 ka B.P.开始河流沉积作用超过海面高度,莱州湾开始逐步成陆的过程。研究表明,莱州湾地区东部的鲁东地块相对抬升,造成黑土湖组顶板高出现代海面。西部的济阳坳陷区沉降较大,造成黑土湖组埋深较大。莱州湾南岸黑土湖组单元形成的古地形坡度,与现代地形坡度接近,在5.5—8.5 ka B.P.期间的海面变化不大。新的研究结果为更深入认识山东半岛全新世海岸带变化提供了重要依据。展开更多
文摘This paper first introduces procedures leading to the establishment of Late Permian-Middle Triassic sea level change curve of Yangtze platform. Bathymetric curves extracted from curve of habitat types are first transformed to sea level curves stage by stage. Comparison between curves of Yangtze and the world reveals that because the Late Permian marine sequences are lacking in most parts of the world, the Late Permian to Griesbachian curve of Yangtze may serve as an important reference for further revision of the world curve. The Early-Middle Triassic short-term changes of Yangtze are briefly concordant with those of Haq's world curve, whereas their long-term changes are discordant. The latter, however, is representative of the East Asian regions affected by the Indosinian orogeny. Basically the third cycles of Yangtze and the world are only pertly concordant, and even in concordant cases their concrete boundaries are not coincident. This indicater that sea level changes are not strictly synchronous over the world. It seems that the 1st and 2nd cycles (supercycles and megacycles) may be world-wide, but not the 3rd cycles.
文摘In the present paper, the Holocene sea level changes and coastline shifts in Zhejiang, China are discussed, based on the ancient coastline evidence related with sea level changes and 21 14C dat-ings of shell, peat or mud and wood samples along the Zhejiang coast. The development of Zhejiang coastline during the Holocene period can be divided into four stages. A lot of data of historical period and modern times have shown that tracing coastline shifts back to its source, we have to consider tremendous effects of man's activities besides natural factors, such as elevation and subsidence of the earth crust, sea level changes, supply of sediment, and littoral hydrodynamics.
基金The National Natural Science Foundation of China under contract Nos 41576067 and 41576061the Basic Scientific Fund for National Public Research Institutes of China under contract No.2017Q03the National Basic Research Program(973Program)of China under contract No.2010CB951203
文摘Mangroves,widely distributed along the coasts of tropical China,are influenced by Asia monsoon,relative sea level change and enhanced human activity.To predict the impacts of future climate change on mangrove ecosystems,it can be understood by reconstructing past mangrove dynamics using proxies preserved in coastal sediments.In this study,we quantitatively partitioned buried organic matter(OM)sources,collected from a vulnerable mangrove swamp in the Qinzhou Bay of northwestern South China Sea,using a ternary end-member mixing model of δ^13C and C:N values.Mangrove-derived OM(MOM)contribution was used as a tracer for mangrove development since 2.34 cal ka BP.This information,together with paleoclimate records(i.e.,speleothem δ^18O values,sea level change,grain size parameters)and human activity,was used to divide mangrove development into three stages during the late Holocene:relative flourish(2.34-1.13 cal ka BP),relative degradation(1.13-0.15 cal ka BP)and further degradation(0.15-0 cal ka BP).Before 1.13 cal ka BP,mangroves flourished with a high MOM contribution((88.9±10.6)%),corresponding to stable and high sea level under a warm and humid climate.After 1.13 cal ka BP,rapid fall in relative sea level coupled with the strengthening of the Asian winter monsoon,resulted in mangrove degradation and MOM reduction((62.4±18.9)%).Compared with air temperature and precipitation,the relative sea level fall was the main controlling factor in mangrove development before entering the Anthropocene(the time of the Industrial Revolution).After^150 cal a BP,reclamation of mangrove swamps to shrimp ponds is the main factor causing mangrove degradation and MOM reduction.
文摘In view of the huge ice cover of 24. 5× 106 km3 in Antarctica, which accounts for over 90 % by volume of the ice body on earth, the movement of Antarctic glaciers is a major control on global sea-level change and climatic fluctuation. As recorded in the Quaternary deposits in King George Island, West Antarctica, three rapid ablations can be recognized at 11000, 9000 and 6100 years ago and the global climate within the past 6000 years is characterized by small-amplitude warm-cold fluctuation. Intertidal deceits at the north bank of the Shenzhen Bay suggest a periodic variation in sea level in about every 670 years over the last 6000 years with low sea levels recorded in the periods of 5500 - 4900, 3900 - 3600, 2400 2200 and 1300 - 1200 years ago. Between these periods the sea level rised for about 80 cm onaverage. The modern warming climate in the last century corresponds with a rise of sea level atthe rate of 2 - 3 mm/a.
文摘According to the latest International Chronostratigraphic Scheme (ICS, 2000), the Permian in the Middle Lower Yangtze region of South China can be divided into three series and nine stages relevant to the traditional six stages of South China. From Assellian to Changxingian of Permian, 44 Ma in age range, the strata are composed of 14 third order sequences, each of which is 3.14 Ma in average age range. There is one third order sequence of Zisongian, equivalent to middle and upper Chuanshan Formation or equal to Asselian and two thirds of Sakmarian. There are two third order sequences, corresponding to Liang shan Formation or Zhenjiang Formation and upper Chuanshan Formation, which are assigned to Longlingian, coinciding with Artinskian and one third of Sakmarian. In addition, three third order sequences, equal to Qixia Formation, are attributed to Chihsian, corresponding to Kubergandian and one third of Roadian. Four third order sequences, comprising Gufeng, Maokou, Yanqiao, Yinping and Wuxue formations, are assigned to Maokouan, equivalent to two thirds of Roadian, Wordian and Capitanian. Two third order sequences, equal to Longtan Formation or Wujiaping Formation, are included in Wuchiapingian. Other two third order sequences, corresponding to Changxing Formation or Dalong Formation, are assigned to Changhsingian. In brief, these above third order sequences can be incorporated into 4 sequences sets.
基金National Natural Science Foundation of China, No.40871020 Guangdong Natural Science Foundation, No.7005836
文摘Coastal dune rocks in China are eolian sands cemented by calcium carbonate under subaerial conditions, widely distributing on the tropical and subtropical coasts of South China. Particular temperature and precipitation as well as local wave and landform conditions are required for the formation of the dune rocks. A correspondence was found between Holocene environmental changes and coastal dune rock development by comparing the features of the sea-level and climate changes in the Holocene period with the ages, scales, and cementation of the dune rocks on the South China coasts. The findings provide well grounded explanation for some problems unresolved in the past researches on the coastal dune rock in South China： （1） There were no dune rocks with ages older than 6000 years in South China because the dune rocks formed before 6000 a BP were covered by the sea water that rose in the later period; （2） the dune rocks with ages of around 3000 a BP were widely found in South China today because the coastal dunes were cumulated on a large scale at that time as a result of temperature falling after the end of Megathermal; （3） Medieval Warm Period was the main period for the eolian dunes to be cemented into the coastal dune rocks in South China; （4） lack of dune rocks of younger than 1000 a BP was accounted for by that the climate conditions in recent one thousand years were not suitable for the cementation.
文摘Climate change and urbanization issues are the two key factors that make humans liable to be affected by disasters, which are overlapped in urban agglomeration. The five big urban agglomerations of China with strong economic power are the important engines for national economic and social development. However, being in the sea-land mutual interaction belts with a vast hazard-bearing body, they are affected by sea-land compound disasters, and are liable to suffer heavy disaster losses with climate change. It is suggested that government departments concerned should fully recognize the impact of climate change on coastal urban agglomerations, propose strategies as soon as possible, and integrate the impact of climate change and adaptation countermeasures into the various kinds of social-economic development plans for coastal urban regions.
基金the National Natural Science Foundation of China (Grant No. 40272016) the State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology,CAS (Grant No.043105)
文摘Sedimentary environment and distribution of brachiopods during the Changhsingian in Xingwen, Si-chuan Province of the upper Yangtze region, are statistically analyzed. Changing regularity in diversity of brachiopod is synthetically investigated based on qualitative and quantitative analysis of transgres-sion-regression cycles. The results show that the diversity of brachiopods in this region in the trans-gression (aggradation) sequence is higher than that in the regression (progradation) sequence. The brachiopods in this area began to diversify in the early Changhsingian. And the species diversity had four peak stages which are respectively in the middle Early Changhsingian, late Early Changhsingian, early Late Changhsingian and late Late Changhsingian. The species diversity reached its highest in the late Late Changhsingian but this is followed by a sharp decrease at the end-hanghsingian, indicating the mass extinction of most brachiopod species which were prosperous in the Late Paleozoic.
基金National Natural Science Foundation of China,No.41301012,No.41771020Natural Science Foundation of Fujian Province,No.2020J01185。
文摘The lower reaches of the Minjiang River and its adjacent areas were among the most active prehistoric archaeological areas in Fujian Province.The accumulation types of Neolithic archaeological strata are roughly divided into dune sites and dune/shell mound sites.The sites can also be roughly divided into estuarine,coastal,and sea-island sites based on their geomorphic features.The cultural development of these prehistoric sites is of great significance for understanding the migration and spread of Austronesian civilization.Based on luminescence dating of typical Neolithic sites on Haitan Island,their quartz-OSL(optically stimulated luminecesence)burial ages were determined.Synthesizing previously published results,the temporospatial distribution characteristics of the sea-island sites on Haitan Island are discussed,and the relationship between Neolithic human activities and regional geomorphic processes is analyzed.The results show that:(1)the spatial and temporal distribution of the Haitan Island Neolithic sites are closely related to small-scale geomorphic features and are controlled by mesoscale geomorphic processes.The sites were mainly distributed in the foothills of two high hills along an NNE-SSW trend.With an increase in altitude,the features were distributed as“single site(I)–superimposed site–single site(II)”and appear successively.Single type sites(I)mainly appeared at low sea level,whereas single type sites(II)mainly appeared at high sea level.Superimposed sites were not subject to sea level changes.The relative elevation of the superimposed sites in the study area indicates the optimal residential area for human activities in the region.The single site with an elevation lower than the optimal residential area was mainly restricted by the lowest residential area,whereas the single site at a higher elevation than the optimal residential area was mainly affected by livelihood patterns.(2)High sea level caused by the“backwater effect”in low latitude areas in the southern hemisphere,and coastal aeolian sand activity influenced by sea level fluctuations in the middle Holocene correspond well with human activities recorded in the cultural stratigraphy of sea-island type sites.The altitude of coastal aeolian sand accumulation can be used as an indirect index to estimate the age of coastal dunes.
基金Key Project of National Natural Science Foundation of China, No.40730527
文摘Based on 22 sparse-distributed tide gauge records in the Northwest Pacific Ocean marginal sea, the process, characteristic and prediction of regional sea level change are discussed by the integration of the following methods. Firstly, the regularized EM algorithm （RegEM） and the Multi-taper Spectral Method （MTM） are adopted to interpret their multiscale fluctuation processes and their spatial-temporal variations. Secondly, the orderly cluster method is introduced to classify these tidal stations, and with the consideration of the space adjacent relation, we obtain five sub-regions （the coasts of Bohai Sea-northern Yellow Sea, Yellow Sea-East China Sea along Chinese coast, the East China Sea along Japanese coast, the southern East China Sea and the northwestern South China Sea）. Furthermore, the Mean Generation Function （MGF） is explored to predict the medium- and long-term trends of each tide station. Finally, the Principal Component Analysis （PCA） is employed to obtain regional-scale sea level change trends, sea level rise rates of the above five sub-regions from 2001 to 2030 are 1.23-1.27 mm/a, 3.30-3.34 mm/a, 2.72-2.76 mm/a, 1.43-1.47 mm/a and 1.13-1.15 mm/a respectively, and the whole region sea level rise rate is between 2.01 mm/a and 2.11 mm/a. The aim of our work is to conduct an integrated research on regional sea level change.
文摘地质调查发现,山东半岛西北部的莱州湾滨海地区普遍发育黑土湖组滨海湖沼相、潟湖相沉积,其下伏末次盛冰期泛滥平原相沉积,上覆全新世中晚期海侵层。黑土湖组的分布受古地形和全新世海侵的影响,其形成时代为8.5—5.5 ka B.P.,即由现代海岸线附近因8.5 ka B.P.前后海面上升环境效应开始出现,向陆地方向逐渐过渡到最大海侵线附近的5.5—6.0 ka B.P.期间形成。该地层单元的穿时性指示了海侵向陆地方向的推进,以及大约自5 ka B.P.开始河流沉积作用超过海面高度,莱州湾开始逐步成陆的过程。研究表明,莱州湾地区东部的鲁东地块相对抬升,造成黑土湖组顶板高出现代海面。西部的济阳坳陷区沉降较大,造成黑土湖组埋深较大。莱州湾南岸黑土湖组单元形成的古地形坡度,与现代地形坡度接近,在5.5—8.5 ka B.P.期间的海面变化不大。新的研究结果为更深入认识山东半岛全新世海岸带变化提供了重要依据。
