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近20多年来,随着古海洋学研究的深入和氧同位素分馏机理方面的探讨,人们对海洋沉积岩芯中浮游有孔虫样品δ~(18)O变化的控制因素,有比较清楚的认识,其变化主要取决于当时海水的δ~(18)O和表层水温的变化.HY4-901柱状样位于南海北部陆坡18°49′N113°28′E,水深1120m..l 沉积特征该柱状剖面沉积连续,粒度均匀,颜色也较均一.以粉砂质粘土为主,少量粘土质粉砂,未见非正常沉积,富含浮游有孔虫、钙质超微化,硅藻、放射虫也较丰富,为典型的上陆坡沉积.2 分析方法及稳定同位素特征本柱状样长250cm,其中0～100cm段,按1cm连续取样;10～250cm段,按2cm取样,共取175个样品作碳、氧稳定同位素分析.样品先用0.063mm孔径的筛进行冲洗之后进行有孔虫鉴定,并挑选其中个体大小接近的袋拟抱球虫作稳定同位素测定.样品在甲醇中用超声波清洗后,放在小玻璃舟内压碎,放入350℃炉内烘烤去除有机质,在0,5Pa的真空条件下与无水磷酸反应生成二氧化碳,去水后,通入质谱进行测定.
In recent 20 years, with the deepening of paleoceanographic research and the mechanism of oxygen isotope fractionation, there is a clear understanding of the controlling factors for δ 18 O changes in planktonic foraminifer samples in marine sedimentary cores. The variation mainly depends on the variation of seawater δ 18 O and surface water temperature at the time.The type of HY4-901 columnar is located in the northern slope of the South China Sea 18 ° 49’N113 ° 28’E and the water depth is 1120m .. Sedimentary characteristics The columnar section sediment Continuous, uniform particle size, more uniform color, mainly silty clay, a small amount of clayey silt, no abnormal deposition, rich in planktonic foraminifera, calcareous superfine, diatoms and radiolarian Rich, as a typical Shangluo deposition.2 Analysis and stable isotope characteristics of the columnar sample length 250cm, of which 0 ~ 100cm section, 1cm continuous sampling; 10 ~ 250cm section, according to 2cm sampling, a total of 175 samples taken as carbon, Oxygen-Stable Isotope Analysis Samples were first identified by foraminifera with a 0.063-mm-mesh sieve and sturgeon-type coccidia were selected for their stable isotopes, and the samples were cleaned with ultrasonic in methanol, Small glass boat crushed into the oven at 350 ℃ drying Removal of organic matter, under vacuum 0,5Pa with anhydrous phosphoric acid to form carbon dioxide, to the water, through the mass was measured.