作　　者： ; ; ; ; ;

机构地区： 中山大学地球科学系

出　　处： 《海洋学报》 2011年第3期103-113,共11页

摘　　要： 研究钻孔DGKS-9602位于冲绳海槽中部,岩芯长度为931 cm,钻孔年代覆盖了氧同位素1～4阶段,年代可追溯至距今73 ka。孢粉分析结果证明,孢粉带与氧同位素阶段有较好的对应关系,其中松属花粉与蒿属花粉比值(P/A)与海平面变化曲线相互吻合。应用非相似性类比法将钻孔孢粉样品与陆地表土孢粉样品进行欧氏距离计算,从而获得陆源物质来源的可能区域,进而分析了海平面波动下导致陆源区发生的可能变化。结果证明在MIS 4～3阶段和全新世均以松属花粉为主,其类比分析结果表明,它们与现代陆地样点孢粉组合的相似度都较差,反映了分散的陆地来源和风力搬运为主导。而在末次盛冰期阶段,孢粉中的松属与蒿属的比值急剧下降至小于1,类比结果显示该段陆源物质很可能来自于盛冰期出露的大陆架平原,且以草地-湿地植被为主,该阶段海槽的离岸距离大为缩短,河流输入导致陆源物质通量增加。研究表明在冰期-间冰期时间尺度上,中国东部海岸带与冲绳海槽之间的离岸距离变化是制约陆源孢粉物质通量变化和搬运介质改变的主要因素。为更好地理解海洋沉积物孢粉的物质的来源以及解释复杂的古植被和古气候信息奠定了基础。 Core DGKS-9602 is located in the middle Okinawa Through.The total length of the core is 931 cm and 88 samples were collected from the core.the core age appears to cover marine isotope stages（MIS） 1～4,with the oldest age at upproximatedly 73 ka BP.A pollen analysis from the core indicates that there is a strong relationship between pollen zones and oxgyen isotope stages.The curve of ratio between Pinus and Artemisia（P/A） is concordance with sea-level change of the region.Fossil pollen and modern surface pollen were used to calculate the Euclidean distance by non-similarity analogy and to estimate the pollen source areas,which made it possible for further study on the changes of the terrigenous matter source regions under different sea-level conditions.The results show that during MIS 4 the main source of pollen is the north region of the Okinawa Through,which is dominated by coniferous forest.At the MIS 3 stage,the sea-level is relatively high,and the eastern China（the Middle and Lower Changjiang River） and Kyushu may be the main source areas during this period where the mountain conifers mix with some broad-leaved plants dominated the forests.During MIS 2,the sea level declined dramatically,that is ′coincided with P/A ratio by dropping sharply to 1.The pollen analogue study shows that the pollen grains at last glacial maximum（MIS 2） may be mostly derived from the vicinal continental shelf plains in a short transport distance where the vegetation is predominated by grassland and wetland.Regarding to the Holocene,the result indicates a wide and diverse source areas,including the Changjiang River and the Huanghe River in China,as well as the water current of Kuroshio flowing from tropical regions.

关 键 词： 冲绳海槽 孢粉分析 古植被 海平面变化 孢粉物源

领　　域： [天文地球] [天文地球] [天文地球]