南海碎屑沉积物化学组成的气候记录

CLIMATIC RECORDS IN THE MAJOR ELEMENTS OF THE TERRESTRIAL DETRITUS FROM THE SOUTH CHINA SEA

取自南海北部陆坡的ODP1144站沉积物中碎屑组分的主量元素含量表现出气候控制的变化特征,其中在间冰期,碎屑物质表现出较高的Al/Ti、K/Ti、Mg/Ti比值和较低的Na/Ti、Ca/Ti比值,而在冰期则正好相反。这些碎屑物质主要来自华南地区的陆壳风化产物,其所表现出来的主量元素变化特征意味着在间冰期华南地区陆壳化学风化程度加强,反映一种相对湿润的气候环境。这种气候环境可能是间冰期东亚季风系统中的夏季风加强所致。

Major elements of the terrestrial detritus in the sediments collected from ODP site 1144 in the South China Sea were reported in this paper. The Ti normalized ratios of the major elements exhibit significant climatecontrolling patterns. In details, during interglacials, the Al/Ti, K/Ti and Mg/Ti ratios were higher than during glacials, while Na/Ti and Ca/Ti ratios were lower than those during glacials. Considering that these terrestrial detritus mainly come from weathering products in South China, such variations of major element indicate that chemical weathering in South China was strong during interglacials. The enhanced chemical weathering might have something to do with the more humid climate in interglacials than in glacials, which agrees with pollen records in the sediment cores from SCS. Such climate patterns indicate that summer monsoons were strengthened during interglacials, which brought about more precipitation to South China and enhanced the chemical weathering there.