Specimens of Amersinia obtrullata and Beringiaphyllum pseudoantiquum in Paleocene Wuyun flora, Heilongjiang Province, Northeast China, were described and assigned to Cornaceae sensu. Infructescences formally allocated...Specimens of Amersinia obtrullata and Beringiaphyllum pseudoantiquum in Paleocene Wuyun flora, Heilongjiang Province, Northeast China, were described and assigned to Cornaceae sensu. Infructescences formally allocated in Trochodendron sp. were reviewed and assigned to Amersinia obtrullata. Leaves described as Populus carneosa, Celastrophyllum subprotophyllum, Viburnum antiquum, V. asperum, Viburniphyllum finale, Protophyllum wuyunense, P. cf. haydenii, P. ovatifolium, Credneria inordinata were also restudied and assigned to Beringiaphyllum pseudoantiquum.展开更多
Late Paleozoic strata in northeastern China are distributed in a zonal pattern around the old-land on the Jiamusi-Mongolia Block. They are composed of active deposits in the regular distributed tectonic lithofacies zo...Late Paleozoic strata in northeastern China are distributed in a zonal pattern around the old-land on the Jiamusi-Mongolia Block. They are composed of active deposits in the regular distributed tectonic lithofacies zones. This indicates that the late Paleozoic strata belong to continental margin deposits. According to the strong conformability of the sedimentary strata in the same continental margin and distinct differences among the three continental margins, three stratigraphical regions of the Jiamusi-Mongolia Stratigraphical Province are recognized along the northern, southern and eastern margins of the Jiamusi-Mongolia Block, named respectively as Xing＇an Stratigraphical Region, Inner Mongolia grass-Songhua River Stratigraphical Region and Baoqing-Hunchun Stra- tigraphical Region. Due to the characteristics of continental margin deposits and active sediments, the strata can be correlated on the level of formation by the methods of analysing the rock association in the same stratigraphic region. Therefore, some revisions of the lithologieal formations of the late Paleozoic strata in northeastern China have been made, and a new chart of lithostratigraphic correlation has been proposed. Furthermore, the present stratigraphic framework is setting on the International Stratigraphic Chart on the level of stage, after comprehen- sive researches to lithostratigraphy, biostratigraphy and chronostratigraphy, especially the conodont biostratigra- phy and isotopic ages of volcanic rocks obtained in recent years.展开更多
Based on the data about sedimentary facies and palaeogeography, this paper proves the existence of the Cathaysia (the part in eastern Zhejiang and northern Fujian, the same hereinafter) and makes a survey about its pa...Based on the data about sedimentary facies and palaeogeography, this paper proves the existence of the Cathaysia (the part in eastern Zhejiang and northern Fujian, the same hereinafter) and makes a survey about its palaeogeography since Sinian Period. It also discusses the evolution of the tectonic environment of this region during Phanerozoic Eon, according to the features such as the composition of sandstones derived from the old land and alkalinity of volcanic rocks and so on. Continuous uplifting was maintained in Cathaysia during Sinian Period and Paleozoic Era, typically with no significant tectono-magmatic activity being observed. Its northwestern margin belongs to the type of passive continental margin during the middle and late phase of Caledonian Cycle. It showed the characteristics of a steady continent in late Paleozoic era, but was turned quickly into an active continental margin after the middle Jurassic period.展开更多
Discovered in the late 1980s, inactive ice wedges in Yitulihe in the north part of Da Hinggan Mountains, Northeastern China are the southernmost in the Northern Hemisphere, and they are important paleo-environmental i...Discovered in the late 1980s, inactive ice wedges in Yitulihe in the north part of Da Hinggan Mountains, Northeastern China are the southernmost in the Northern Hemisphere, and they are important paleo-environmental indicators. Recently, research was carried out to analyze the hydrogen and oxygen isotopes of an inactive ice wedge from them. The plot of stable isotopes reveals three periods of temperature fluctuations centered approximately at 2.8, 2.3 and 1.9 ka BP. And the resultant temperature was probably lowered by about 2.1, 1.1, and 1.3℃, respectively, in comparison with present temperatures. In conjunction with previous studies, pollen record and radiocarbon dating, the ice wedges probably developed between 3.3 to 1.6 ka BP, and the southern limit of the permafrost （SLP） at that time advanced southwards by around 2°N, i.e., about 200 km.展开更多
文摘Specimens of Amersinia obtrullata and Beringiaphyllum pseudoantiquum in Paleocene Wuyun flora, Heilongjiang Province, Northeast China, were described and assigned to Cornaceae sensu. Infructescences formally allocated in Trochodendron sp. were reviewed and assigned to Amersinia obtrullata. Leaves described as Populus carneosa, Celastrophyllum subprotophyllum, Viburnum antiquum, V. asperum, Viburniphyllum finale, Protophyllum wuyunense, P. cf. haydenii, P. ovatifolium, Credneria inordinata were also restudied and assigned to Beringiaphyllum pseudoantiquum.
基金Supported by Project of China Geological Survey (No. 1212011120153 - 3)
文摘Late Paleozoic strata in northeastern China are distributed in a zonal pattern around the old-land on the Jiamusi-Mongolia Block. They are composed of active deposits in the regular distributed tectonic lithofacies zones. This indicates that the late Paleozoic strata belong to continental margin deposits. According to the strong conformability of the sedimentary strata in the same continental margin and distinct differences among the three continental margins, three stratigraphical regions of the Jiamusi-Mongolia Stratigraphical Province are recognized along the northern, southern and eastern margins of the Jiamusi-Mongolia Block, named respectively as Xing＇an Stratigraphical Region, Inner Mongolia grass-Songhua River Stratigraphical Region and Baoqing-Hunchun Stra- tigraphical Region. Due to the characteristics of continental margin deposits and active sediments, the strata can be correlated on the level of formation by the methods of analysing the rock association in the same stratigraphic region. Therefore, some revisions of the lithologieal formations of the late Paleozoic strata in northeastern China have been made, and a new chart of lithostratigraphic correlation has been proposed. Furthermore, the present stratigraphic framework is setting on the International Stratigraphic Chart on the level of stage, after comprehen- sive researches to lithostratigraphy, biostratigraphy and chronostratigraphy, especially the conodont biostratigra- phy and isotopic ages of volcanic rocks obtained in recent years.
文摘Based on the data about sedimentary facies and palaeogeography, this paper proves the existence of the Cathaysia (the part in eastern Zhejiang and northern Fujian, the same hereinafter) and makes a survey about its palaeogeography since Sinian Period. It also discusses the evolution of the tectonic environment of this region during Phanerozoic Eon, according to the features such as the composition of sandstones derived from the old land and alkalinity of volcanic rocks and so on. Continuous uplifting was maintained in Cathaysia during Sinian Period and Paleozoic Era, typically with no significant tectono-magmatic activity being observed. Its northwestern margin belongs to the type of passive continental margin during the middle and late phase of Caledonian Cycle. It showed the characteristics of a steady continent in late Paleozoic era, but was turned quickly into an active continental margin after the middle Jurassic period.
基金supported by National Natural Science Foundation of China (Grant No. 40901044)Chinese Academy of Sciences (CAS) 100-Talent Program (Grant No. 2004407)+1 种基金Scholarships for Young Scientists of the State Key Laboratory of Frozen Soils Engineering (Grant No. SKLFSE-ZQ-04)Talent Fund of the Cold and Arid Regions Environmental and Engineering Research Institute, CAS (Grant No. O984971001)
文摘Discovered in the late 1980s, inactive ice wedges in Yitulihe in the north part of Da Hinggan Mountains, Northeastern China are the southernmost in the Northern Hemisphere, and they are important paleo-environmental indicators. Recently, research was carried out to analyze the hydrogen and oxygen isotopes of an inactive ice wedge from them. The plot of stable isotopes reveals three periods of temperature fluctuations centered approximately at 2.8, 2.3 and 1.9 ka BP. And the resultant temperature was probably lowered by about 2.1, 1.1, and 1.3℃, respectively, in comparison with present temperatures. In conjunction with previous studies, pollen record and radiocarbon dating, the ice wedges probably developed between 3.3 to 1.6 ka BP, and the southern limit of the permafrost （SLP） at that time advanced southwards by around 2°N, i.e., about 200 km.
