马里亚纳海槽57KL和61KL岩芯火山碎屑特征

A Study on the Feature of Volcanogenic Material in Mariana Trough Sediments

在马里亚纳海槽(18°N)附近的沉积岩芯中,火山碎屑物质丰富,且夹有数目不等的火山灰层。火山碎屑的组合特征反映了本区主要以基性火山喷发产物为主。原生火山灰层基本上代表着相邻区域的火山喷发次数。同时,在一定的构造部位,浊流沉积对火山灰层的分布有一定影响作用。本文对位于不同构造背景两沉积岩芯的岩屑,玻屑和晶屑进行了鉴定,并对火山灰层的垂向分布规律与火山活动之间的关系,进行了重点讨论。

Two sediment cores from Mariana Trough (located at 18°N)are both rich in volcanogenic debris with a number of ash layers. According to the components of the pyroclastic, the investigated area is dominated by basic volcanic rocks. Distinctive tephra layers represent essentially instantaneous geological events. However, tephra layers are often deposited by turbidity currents. Identification of the pyroclastics of the two cores was undertaken which are located in different geological settings. The investigation of the vertical ash layer shows that it can be linked with volcanic eruption.