The Cretaceous was one of the most remarkable ＇greenhouse＇ climate periods in geological history. Most of the reported studies of the Cretaceous paleoclimate are based upon marine sedimentary records. Large spatial ...The Cretaceous was one of the most remarkable ＇greenhouse＇ climate periods in geological history. Most of the reported studies of the Cretaceous paleoclimate are based upon marine sedimentary records. Large spatial scale paleoclimatic reconstruction, which has a higher time resolution based upon continental sediments in China, is rarely found. This study presents paleoclimate reconstruction for the six time periods of the Early Cretaceous in China by employing continental climate-indicative sediments, including calcareous deposits, coal, oil shale, gypsum, halite, desert sedimentary systems, ferruginous deposits and laterite, copper-bearing deposits, limestone and dolomite. Based on the distribution of the association of climate-indicative sediments and the influences of paleotopography and orogenic belts （or important structural belts） on climate, seven climatic zones have been identified： 1） a warm and humid zone; 2） a warm and humid-warm and arid zone; 3） a warm and arid zone; 4） an arid and hot zone; 5） the Tibet hot and humid zone; 6） a hot and arid-semiarid zone; and 7） a hot and humid-hot and arid one. It is found that the Early Cretaceous climatic zones of China were nearly latitudinally distributed from northwest to southeast. The arid- hot climatic zone expanded in the Aptian, suggesting that a hotter and drier climate prevailed in later period of the Early Cretaceous. Conversely, the humid climatic zone expanded in the Albian, indicating that a wetter climate appeared at the end of the Early Cretaceous. The overall distribution pattern of the seven climatic zones indicates that a hot-warm and arid climate was predominant in China; this coincides with a global ＇greenhouse climate＇ background. However, palaeogeographic features and specific geologic events, such as the existence and disappearance of the eastern high plateau, and the uplift and denudation of Yinshan, Yanshan, Tianshan, Qinling and Dabie Mountains, led to distinctive regional climatic features of the Cretaceous in China.展开更多
Late Cretaceous lacustrine deposits in Songliao Basin provide a unique material to study the paleo-environment and paleoclimate of nomarine Cretaceous.Two large transgressions occurred during the Qingshankou and Nenji...Late Cretaceous lacustrine deposits in Songliao Basin provide a unique material to study the paleo-environment and paleoclimate of nomarine Cretaceous.Two large transgressions occurred during the Qingshankou and Nenjiang deposition times,the later of which was larger.Based on sedimentation,ostracode,TOC,HI,δ<sup>13</sup>C<sub>org</sub> and C/N from upper Yaojia Formation to Lower Nenjiang Formation in the eastern Songliao Basin。展开更多
The Cretaceous is among the most unusual eras in the geological past. Geoscience communities have been having great concerns with geological phenomena within this period, for example carbonate platforms and black shal...The Cretaceous is among the most unusual eras in the geological past. Geoscience communities have been having great concerns with geological phenomena within this period, for example carbonate platforms and black shales in the Early and Middle Cretaceous respectively, during the last decades. But few people have paid any attention to the set of pelagic redbeds lying on the black shales, not to mention the applications to paleoclimatology and paleoceanography. It is shown by the sedimentary records of redbeds, that they were deposited around the CCD, with both a higher content of iron and much lower concentrations of organic carbon, which implies conditions with a relatively high content of oxygen. Such redbeds occurred in the global oceans, mainly in the Tethyan realm, with different durations of deposition and a climax from the late Santonian to early Campanian. Global cooling and dramatic changes in ocean currents might help to increase the oxygen flux between the atmosphere and ocean, after the large scale organic carbon burial during the Middle Cretaceous, and therefore lead to the oxygenation of deep ocean and so the occurrence of late Cretaceous oceanic redbeds.展开更多
The sedimentary background and sedimentary environment of the Lower Cretaceous of Lingshan Island,Shandong,remain unclear.There is considerable controversy as to whether the sedimentary environment was marine or conti...The sedimentary background and sedimentary environment of the Lower Cretaceous of Lingshan Island,Shandong,remain unclear.There is considerable controversy as to whether the sedimentary environment was marine or continental.In this study,analyses were conducted with respect to indicators of paleosalinity,the chemical composition of clay,paleobiota,the characteristics of strata exhibiting salinization in eastern China during the Early Cretaceous,and the relationship between paleosalinity and paleoclimate.The results indicate that the sedimentary environment of the Lower Cretaceous Laiyang Group of Lingshan Island was that of a salified lake rather than a marine environment.This study not only provides a reference for determining the sedimentary environment of the Lower Cretaceous Laiyang Group of Lingshan Island but also offers a new perspective for the study of Cretaceous strata with salinization characteristics in eastern China.展开更多
Although the paleoclimate of the marine Cretaceous has been well studied, the paleoclimate of the non-marine is still not well understood. The Songliao Basin was one of the largest non-marine rift basins during Cretac...Although the paleoclimate of the marine Cretaceous has been well studied, the paleoclimate of the non-marine is still not well understood. The Songliao Basin was one of the largest non-marine rift basins during Cretaceous. The Well-preserved Cretaceous lacustrine deposits in this basin provide a unique opportunity to study terrestrial paleoenvironments and paleoclimate during the Late Cretaceous. Here, the microfossils from the Late Turonian Qingshankou Formation of the Songliao Basin were used to investigate the paleoenvironments and paleoclimate of east Asia. There are two spore and pollen assemblages recognized: a Cedripites-Cyathidites-Classopollis assemblage from Upper Member 1, and a Cedripites-Cyathidites-Classopollis assemblage from Lower Member 2 of the Qingshankou Formation, respectively. Besides, relatively abundant ostracods have been identified. In the Songliao Basin, the climate was relatively warm and wet during Late Turonian, with good source rock deposited in the Songliao lake.展开更多
基金supported by National Key Basic Research Program of "973" Project (Grant No.2012CB822003,2006CB701401-03)the Project of the National Natural Science Foundation of China (Grant No.41072083)the Cultivating Program of Young and Middle-aged Backbone Teachers of Chengdu University of Technology
文摘The Cretaceous was one of the most remarkable ＇greenhouse＇ climate periods in geological history. Most of the reported studies of the Cretaceous paleoclimate are based upon marine sedimentary records. Large spatial scale paleoclimatic reconstruction, which has a higher time resolution based upon continental sediments in China, is rarely found. This study presents paleoclimate reconstruction for the six time periods of the Early Cretaceous in China by employing continental climate-indicative sediments, including calcareous deposits, coal, oil shale, gypsum, halite, desert sedimentary systems, ferruginous deposits and laterite, copper-bearing deposits, limestone and dolomite. Based on the distribution of the association of climate-indicative sediments and the influences of paleotopography and orogenic belts （or important structural belts） on climate, seven climatic zones have been identified： 1） a warm and humid zone; 2） a warm and humid-warm and arid zone; 3） a warm and arid zone; 4） an arid and hot zone; 5） the Tibet hot and humid zone; 6） a hot and arid-semiarid zone; and 7） a hot and humid-hot and arid one. It is found that the Early Cretaceous climatic zones of China were nearly latitudinally distributed from northwest to southeast. The arid- hot climatic zone expanded in the Aptian, suggesting that a hotter and drier climate prevailed in later period of the Early Cretaceous. Conversely, the humid climatic zone expanded in the Albian, indicating that a wetter climate appeared at the end of the Early Cretaceous. The overall distribution pattern of the seven climatic zones indicates that a hot-warm and arid climate was predominant in China; this coincides with a global ＇greenhouse climate＇ background. However, palaeogeographic features and specific geologic events, such as the existence and disappearance of the eastern high plateau, and the uplift and denudation of Yinshan, Yanshan, Tianshan, Qinling and Dabie Mountains, led to distinctive regional climatic features of the Cretaceous in China.
文摘Late Cretaceous lacustrine deposits in Songliao Basin provide a unique material to study the paleo-environment and paleoclimate of nomarine Cretaceous.Two large transgressions occurred during the Qingshankou and Nenjiang deposition times,the later of which was larger.Based on sedimentation,ostracode,TOC,HI,δ<sup>13</sup>C<sub>org</sub> and C/N from upper Yaojia Formation to Lower Nenjiang Formation in the eastern Songliao Basin。
基金The research is jointly supported by the Key Project of the National Natural Science Foundation of China(No.40332020)Prophase Special Research of Vital Projects in the Basic Research of the Ministry of Science and Technology of China(No.2001CCA01 800)International Geological Correlation Program(IGCP463/494).
文摘The Cretaceous is among the most unusual eras in the geological past. Geoscience communities have been having great concerns with geological phenomena within this period, for example carbonate platforms and black shales in the Early and Middle Cretaceous respectively, during the last decades. But few people have paid any attention to the set of pelagic redbeds lying on the black shales, not to mention the applications to paleoclimatology and paleoceanography. It is shown by the sedimentary records of redbeds, that they were deposited around the CCD, with both a higher content of iron and much lower concentrations of organic carbon, which implies conditions with a relatively high content of oxygen. Such redbeds occurred in the global oceans, mainly in the Tethyan realm, with different durations of deposition and a climax from the late Santonian to early Campanian. Global cooling and dramatic changes in ocean currents might help to increase the oxygen flux between the atmosphere and ocean, after the large scale organic carbon burial during the Middle Cretaceous, and therefore lead to the oxygenation of deep ocean and so the occurrence of late Cretaceous oceanic redbeds.
基金supported by the Fund from the Key Laboratory of Stratigraphy and Palaeontology,Ministry of Natural Resources(Grant No.KLSP 190102)the Graduate Scientific and Technological Innovation Project Financially Supported by Shandong University of Science and Technology(Grant No.SDKDYC 190104)。
文摘The sedimentary background and sedimentary environment of the Lower Cretaceous of Lingshan Island,Shandong,remain unclear.There is considerable controversy as to whether the sedimentary environment was marine or continental.In this study,analyses were conducted with respect to indicators of paleosalinity,the chemical composition of clay,paleobiota,the characteristics of strata exhibiting salinization in eastern China during the Early Cretaceous,and the relationship between paleosalinity and paleoclimate.The results indicate that the sedimentary environment of the Lower Cretaceous Laiyang Group of Lingshan Island was that of a salified lake rather than a marine environment.This study not only provides a reference for determining the sedimentary environment of the Lower Cretaceous Laiyang Group of Lingshan Island but also offers a new perspective for the study of Cretaceous strata with salinization characteristics in eastern China.
文摘Although the paleoclimate of the marine Cretaceous has been well studied, the paleoclimate of the non-marine is still not well understood. The Songliao Basin was one of the largest non-marine rift basins during Cretaceous. The Well-preserved Cretaceous lacustrine deposits in this basin provide a unique opportunity to study terrestrial paleoenvironments and paleoclimate during the Late Cretaceous. Here, the microfossils from the Late Turonian Qingshankou Formation of the Songliao Basin were used to investigate the paleoenvironments and paleoclimate of east Asia. There are two spore and pollen assemblages recognized: a Cedripites-Cyathidites-Classopollis assemblage from Upper Member 1, and a Cedripites-Cyathidites-Classopollis assemblage from Lower Member 2 of the Qingshankou Formation, respectively. Besides, relatively abundant ostracods have been identified. In the Songliao Basin, the climate was relatively warm and wet during Late Turonian, with good source rock deposited in the Songliao lake.
