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通过对南海南部巽他陆坡底部MD05-2895孔末次冰期发育的浊流沉积物进行激光粒度和XRF岩芯元素扫描分析,试图揭示其沉积学和地球化学特性,进而对理解浊流形成过程提供帮助.研究结果显示,浊流沉积层中的碎屑颗粒粒径比正常深海沉积物有大幅度增加,在地球化学成分上表现为Si,K,Ti,Fe等元素异常富集,表明浊流发生时有大量粗颗粒陆源碎屑物质输入.显微观察发现,这些粗颗粒碎屑物质主要由石英、长石、火山玻璃、以及少量含铁含钛重矿物组成,推断应来源于巽他陆架上部的残留沉积,可能与末次冰期时古巽他河输送的陆源物质有关.分析认为这些浊流活动的发生可能与末次冰期时海平面快速变化造成的海岸线大幅移动及沉积物供给不稳定有关,而在单次浊流活动中浊流沉积物的形成主要是受重力(对不同比重、粒级颗粒的)分选的控制.
Through the laser particle size and XRF core elemental scanning analysis of turbidity flow sediments developed in the last glacial stage of the bottom hole of MD05-2895 at the southern Slope of the Southeastern South China Sea in an attempt to reveal their sedimentary and geochemical characteristics and thus help to understand the turbidity flux formation process The results show that the particle size of turbidity flow sediment layer has a significant increase compared with the normal deep-sea sediments, and the geochemical composition shows that Si, K, Ti, Fe and other elements are abnormally enriched, indicating that the turbidity flow occurs There was a large amount of coarse particulate terrigenous debris input.Microscopic observation found that these coarse particulate detritus mainly composed of quartz, feldspar, volcanic glass, and a small amount of iron-bearing titanium heavy minerals, should be derived from the upper part of the 巽 he shelf May be related to the terrigenous materials transported by the Gulu River during the last glacial period.The analysis suggests that the occurrence of these turbidity activities may be related to the sharp movement of the coastline and the unstable sediment supply caused by the rapid sea level change in the last ice age, The formation of turbidity sediment in a single turbidity flow activity is mainly controlled by gravity (for different specific gravities, graded particles).