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沉积物岩心记录着沉积环境的演变过程,其中生物硅(BSi)记录能反映硅质生物的生产力时间和空间变化,2012年5月在下辽河平原西南缘得到了ZK2钻孔柱状样,通过对其沉积物原位密度、生物硅、碳埋藏、粒度、AMS~(14)C和OSL测年、有孔虫鉴定、孢粉鉴定,将ZK2孔的沉积环境主要划分为上三角洲平原相沉积、海洋主导的沉积、湖相沉积、河道沉积4个沉积单元,其相应的生物硅(BSiO_2)浓度分布依次为(2.85±0.23)%、(1.55±0.10)%、(1.96±0.10)%、(0.92±0.05)%,并且生物硅的波动与颗粒有机碳浓度的波动同步。特别是在17~25 cal ka BP冰期形成的湖沼沉积出现较大的颗粒无机碳(PIC)浓度的波动,推测与当时干冷气候条件下CaCO_3过饱和从湖水中沉淀析出有关。钻孔沉积物生物硅浓度记录对格陵兰冰芯~(18)O同位素值的响应存在大约300 a的滞后现象。
The sedimentary core records the evolution of sedimentary environment. The record of biosilica (BSi) can reflect the time and space variation of the productivity of siliceous organisms. In May 2012, the column of ZK2 drilling was obtained on the southwestern margin of the lower Liaohe Plain. Sediment in situ density, biogenic silicon, carbon burial, grain size, AMS ~ (14) C and OSL dating, foraminifera identification and sporopollen identification. The sedimentary environment of ZK2 pore is mainly divided into upper delta plain facies, (2.85 ± 0.23)%, (1.55 ± 0.10)%, (1.96 ± 0.10)%, (0.92 ± 0.18)%, and ± 0.05)%, and the fluctuation of bio-silicon is synchronized with the fluctuations of the concentration of particulate organic carbon. Especially in the lacustrine sediments formed during the 17 ~ 25 cal ka BP glacial period, there is a large fluctuation of the PIC concentration, which is presumed to be related to the precipitation of CaCO_3 supersaturated from the lake in the dry and cold climate. Logging sediment bio-silica concentration has a hysteresis of about 300 a in response to ~ (18) O isotope values of ice cores in Greenland.