A new cranium and two mandibles of Ailuropoda melanoleuca from Xiangxi,Hunan Province are described here.The materials were discovered in a karst cave on the Bamian Mountain at an altitude of 1200 m,with AMC carbon-fo...A new cranium and two mandibles of Ailuropoda melanoleuca from Xiangxi,Hunan Province are described here.The materials were discovered in a karst cave on the Bamian Mountain at an altitude of 1200 m,with AMC carbon-fourteen isotope dating indicating an age of 2800±30 BP.Historically,the giant panda was widely distributed in southern China and parts of Southeast Asia during the Pleistocene epoch,but it is now confined and isolated to six mountain ranges in southwest China’s Sichuan,Shaanxi,and Gansu provinces.The subfossil materials reported here represent the first discovery of the living species of giant panda in Xiangxi,Hunan.This extends their geographical distribution in southern China during the Holocene epoch eastward to the eastern edge of the Yunnan-Guizhou Plateau and their recent altitude range down to 1200 m.展开更多
苦橄岩和科马提岩都是富镁的超镁铁质火山岩，早先，学术界大多关注它们之间的相似性，而对于它们之间的差异性很少强调。于是认为二者的地球化学性质近似，成因类似，形成条件类似。本文采用全数据模式的研究方法，从数据库收集了全球...苦橄岩和科马提岩都是富镁的超镁铁质火山岩，早先，学术界大多关注它们之间的相似性，而对于它们之间的差异性很少强调。于是认为二者的地球化学性质近似，成因类似，形成条件类似。本文采用全数据模式的研究方法，从数据库收集了全球太古宙全部科马提岩和后太古宙全部苦橄岩数据，对比的结果表明，太古宙科马提岩与后太古宙苦橄岩完全不同，它们之间几乎没有可比性。科马提岩与苦橄岩，不仅地球化学特征不同，而且成因不同，形成条件不同，产出时代不同，源区组成也不同。这种不同，反映了太古宙和后太古宙不可能属于同样的构造体制。太古宙是火球时代，地球异常的热，主导的可能是静止盖幔构造（stagnant lid tectonics）；后太古宙是热球时代，地球相对冷了许多，主导的是板块构造（plate tectonics）。科马提岩在太古宙广泛出露，无需地幔柱模式；而苦橄岩在后太古宙很少出露，才真正需要地幔柱模式。展开更多
文摘A new cranium and two mandibles of Ailuropoda melanoleuca from Xiangxi,Hunan Province are described here.The materials were discovered in a karst cave on the Bamian Mountain at an altitude of 1200 m,with AMC carbon-fourteen isotope dating indicating an age of 2800±30 BP.Historically,the giant panda was widely distributed in southern China and parts of Southeast Asia during the Pleistocene epoch,but it is now confined and isolated to six mountain ranges in southwest China’s Sichuan,Shaanxi,and Gansu provinces.The subfossil materials reported here represent the first discovery of the living species of giant panda in Xiangxi,Hunan.This extends their geographical distribution in southern China during the Holocene epoch eastward to the eastern edge of the Yunnan-Guizhou Plateau and their recent altitude range down to 1200 m.
文摘苦橄岩和科马提岩都是富镁的超镁铁质火山岩，早先，学术界大多关注它们之间的相似性，而对于它们之间的差异性很少强调。于是认为二者的地球化学性质近似，成因类似，形成条件类似。本文采用全数据模式的研究方法，从数据库收集了全球太古宙全部科马提岩和后太古宙全部苦橄岩数据，对比的结果表明，太古宙科马提岩与后太古宙苦橄岩完全不同，它们之间几乎没有可比性。科马提岩与苦橄岩，不仅地球化学特征不同，而且成因不同，形成条件不同，产出时代不同，源区组成也不同。这种不同，反映了太古宙和后太古宙不可能属于同样的构造体制。太古宙是火球时代，地球异常的热，主导的可能是静止盖幔构造（stagnant lid tectonics）；后太古宙是热球时代，地球相对冷了许多，主导的是板块构造（plate tectonics）。科马提岩在太古宙广泛出露，无需地幔柱模式；而苦橄岩在后太古宙很少出露，才真正需要地幔柱模式。
