论文部分内容阅读
对菲律宾海西北部奄美三角盆地U1438A孔约350 ka以来沉积物中碎屑组分的粒度组成进行了分析,结果表明,沉积物中碎屑组分的平均粒径为13.1μm,粒径变化范围为0.04~160μm,粒度频率分布呈四峰正偏态分布。利用Weibull分布函数将沉积物碎屑组分的粒度组成分离出4个相对独立的组分。其中超细组分众数约0.3μm,粒度分布范围为0.04~0.9μm,可能是海洋自生黏土。细粒端元众数粒径约3.5μm,粒度分布范围为0.2~32μm,比北太平洋中部风尘略粗,推测主要为来源于亚洲大陆的风尘。粗粒端元众数粒径约10μm,粒度分布范围为0.3~90μm;超粗粒端元众数粒径约40μm,粒度分布范围为3~160μm。粗粒组分和超粗粒组分均主要来自于周围海脊和岛弧的火山物质。细粒和粗粒敏感粒级组分的比值(1.3~2.2μm/28~40μm)与细粒风尘组分和粗粒火山组分的比值(0.9~3μm/>10μm)类似,表现为冰期高、间冰期低,与北太平洋风尘通量、亚洲大陆黄土堆积速率,以及黄土粒径所指示的冰期干旱和东亚季风/西风环流增强的气候变化是一致的,表明冰期由于亚洲大陆的干旱和季风/西风的增强,使得奄美三角盆地中细粒亚洲风尘组分的输入相对增加。因此细粒风尘和粗粒火山物质的比值可以作为亚洲大陆干旱化和大气环流增强的示踪指标。这些研究结果表明奄美三角盆地沉积物的粒度组成可用于重建东亚大陆干旱和大气环流演化历史。
The particle size distribution of the detrital components in the sediments since about 350 ka in the U1438A pore of the Amami triangle basin in the northwestern North Sea of the Argassia of the Philippines shows that the average particle size of the detrital components in the sediments is 13.1 μm, Is 0.04 ~ 160μm, the particle size distribution of the four peaks showed a positive skewed distribution. Four relatively independent components were separated by the Weibull distribution function. The superfine component mode is about 0.3μm, the particle size distribution range is 0.04 ~ 0.9μm, which may be marine authigenic clay. Particle size of the modest particle size of about 3.5μm, particle size distribution range of 0.2 ~ 32μm, dust slightly thicker than the central North Pacific dust, speculated mainly from the dust of the Asian continent. The average particle size of coarse-grained ends is about 10μm and the size distribution ranges from 0.3μm to 90μm. The size of ultra-coarse particles is about 40μm and the size distribution ranges from 3μm to 160μm. The coarse-grained and ultra-coarse-grained components are mainly from the volcanic material of the surrounding ridges and island arcs. The ratios of fine-grained and coarse-grained susceptible fractions (1.3-2.2μm / 28-40μm) are similar to those of fine-grained dust fractions and coarse-grained volcanic fractions (0.9-3 μm /> 10 μm) The low interglacial period is consistent with the increased climatic change in the North Pacific, the loess accumulation rate in the Asian continent, the glacial droughts indicated by the loess particle size and the enhanced East Asian monsoon / westerly circulation, indicating that the glacial period was affected by the drought and monsoon over the Asian continent / Westerly intensification, making the input of fine dust components in the Amami-Triangle Basin relatively increased. Therefore, the ratio of fine dust to coarse volcanic material can be used as a tracing indicator for the intensification of the continent and the enhancement of atmospheric circulation. These findings indicate that the grain-size composition of the sediments in the Amami-Triangle can be used to reconstruct the history of the evolution of the arid and atmospheric circulation over the East Asian continent.