A new geological section recognized in Baishantou of Jiayin,Heilongjiang Province,China,was studied preliminarily in searching for the K/T boundary.An early Paleocene florule characrerized by abundant Tiliaephyllum ts...A new geological section recognized in Baishantou of Jiayin,Heilongjiang Province,China,was studied preliminarily in searching for the K/T boundary.An early Paleocene florule characrerized by abundant Tiliaephyllum tsagajanicum leaves and its associated plants,was collected from the Baishantou Member(new member representing the lower part of the Paleocene Wuyun Formation)overlying the possible K/T boundary.A tuff bed was found from the upper part of the Furao Formation(uppermost Cretaceous)in this section.The new findings imply that the K/T boundary is probable lying in the interval between the base of the Baishantou Member and the tuff bed,based on the correlation of the present strata with the stratotype of the Tsagajan Group spanning the K/T boundary in"Belaya Gara"of the Bureya Basin,Russia.The early Paleocene florule from the Baishantou Member and the early-middle Maastrichtian dinosaurs found from the Yuliangzi Formation underlying the Furao Formation suggest that the Baishantou section is more promising for searching for the K/T boundary in this area.Further studies of the section is needed,integrating paleontological,biostratigraphic,geochemical,paleomagnetic,and sedimentary research would benefit our understanding the mass extinction event and biotic recovery in the Heilongjiang River area,China,and even all of northeast Asia during the K/T boundary interval.展开更多
A 405 cm long core was drilled in the Aparados da Serra National Park (Rio Grande do Sul, Brazil) at the end of 1999, and in all, 23 samples were taken for palynological investigation. The cores’ age is estimated at ...A 405 cm long core was drilled in the Aparados da Serra National Park (Rio Grande do Sul, Brazil) at the end of 1999, and in all, 23 samples were taken for palynological investigation. The cores’ age is estimated at 27 000 a BP based on three radiocarbon dates taken from different depths of the core. Palynological methods were used to reconstruct the history of vegetation and climate change. Four different plant associations were recognized: ① lake plankton and shore plants; ② mire and swamp plants; ③ gallery-forest plants; ④ campos vegetation. Climate changed from cold glacial conditions mainly influenced by the South Pole throughout several transition stages to today’s humid warm climate, mainly being influenced by the Brazil stream.展开更多
基金The authors are grateful for the Project No.30211330496 of the NSFC(China)for the spe-cial financial support of the Jjilin University,China.
文摘A new geological section recognized in Baishantou of Jiayin,Heilongjiang Province,China,was studied preliminarily in searching for the K/T boundary.An early Paleocene florule characrerized by abundant Tiliaephyllum tsagajanicum leaves and its associated plants,was collected from the Baishantou Member(new member representing the lower part of the Paleocene Wuyun Formation)overlying the possible K/T boundary.A tuff bed was found from the upper part of the Furao Formation(uppermost Cretaceous)in this section.The new findings imply that the K/T boundary is probable lying in the interval between the base of the Baishantou Member and the tuff bed,based on the correlation of the present strata with the stratotype of the Tsagajan Group spanning the K/T boundary in"Belaya Gara"of the Bureya Basin,Russia.The early Paleocene florule from the Baishantou Member and the early-middle Maastrichtian dinosaurs found from the Yuliangzi Formation underlying the Furao Formation suggest that the Baishantou section is more promising for searching for the K/T boundary in this area.Further studies of the section is needed,integrating paleontological,biostratigraphic,geochemical,paleomagnetic,and sedimentary research would benefit our understanding the mass extinction event and biotic recovery in the Heilongjiang River area,China,and even all of northeast Asia during the K/T boundary interval.
文摘A 405 cm long core was drilled in the Aparados da Serra National Park (Rio Grande do Sul, Brazil) at the end of 1999, and in all, 23 samples were taken for palynological investigation. The cores’ age is estimated at 27 000 a BP based on three radiocarbon dates taken from different depths of the core. Palynological methods were used to reconstruct the history of vegetation and climate change. Four different plant associations were recognized: ① lake plankton and shore plants; ② mire and swamp plants; ③ gallery-forest plants; ④ campos vegetation. Climate changed from cold glacial conditions mainly influenced by the South Pole throughout several transition stages to today’s humid warm climate, mainly being influenced by the Brazil stream.
