马里亚纳海槽的沉积

SEDIMENTATION OF MARIANA TROUGH

马里亚纳海槽是一个正在扩张的弧后盆地。文章分析中国和联邦德国合作考察马里亚纳海槽两个沉积岩心的一般沉积特征、物质来源及其影响因素。两岩心沉积物均以砂质粉砂、粉砂和粘土质粉砂为主,含较多黑色火山灰层和黑色纹理,岩性分析表明,物质以火山碎屑为主。由于两岩心所处具体构造位置不同,导致岩性、构造和物质来源不同。61KL岩心有4或5个递变层序,为典型的浊流沉积,物质主要来自东部活动的马里亚纳火山弧,由浊流搬运而沉积。57KL岩心物质主要来自海槽扩张裂谷本身的火山喷发。两岩心均为半远洋沉积物。

The Mariana Trough is an active spreading back-arc basin. This paper is concentrated on sedimentary characteristics of two cores from the Mariana Trough. The two cores mainly consist of sandy silt, silt and clayey silt with many black volcanic ash laminations. The lithology of the sediments indicates that volcanic debris is the main composition. Because of their different tectonic positions, the two cores are different in features, structures and sources. There are 4 and 5 graded rhythmites in core 61KL, whicha re typical turbidites transported from the eastern active Mariana Arc. The materials of core 57KL come from volcanic eruption occuring in the trough's own rift valley. Both of the cores are hemipelagic deposits.