70万年来西太平洋暖池北缘上层水体结构演化

发布时间：2018-03-22 07:35

  本文选题：西太平洋暖池　切入点：南极中层水　出处：《中国科学院研究生院(海洋研究所)》2015年硕士论文　论文类型：学位论文

【摘要】：本论文以西太平洋暖池北部边缘的MD06-3047B孔为研究材料,该柱状样由中法合作执行的Marco Polo 2 IMAGES XIV航次取得,该孔位于吕宋岛东部的西菲律宾海本哈姆高原,位于17°00.44’N,124°47.93’E,柱长8.9 m,水深2510 m。本次研究利用该柱状样来研究西太平洋暖池北部边缘过去70万年来的古海洋学变化。通过将底栖种C.wuellerstorfi的δ18O与大洋底栖有孔虫标准曲线LR04曲线进行对比,并以约出现在距今12万年的粉红色G.ruber末现面为参照点建立MD06-3047B孔的年龄模式。结果显示MD06-3047B孔共包括17个氧同位素期次,约70万年。除了G.ruber的δ18O记录在MIS14-13期冰期间冰期变化特征相对不明显,底栖种C.wuellerstorfi、次表层种P.obliquiloculata与表层种G.ruber的δ18O记录整体上具有明显的冰期间冰期变化特征。底栖有孔虫C.wuellerstorfi的碳同位素也具有较为明显的冰期间冰期变化特征,冰期时偏轻,间冰期时偏重;G.ruber的碳同位素变化特征为冰期时逐渐变重,间冰期时逐渐变轻,P.obliquiloculata的碳同位素表现为冰期时逐渐变轻,间冰期时逐渐变重。在冰期终止期Ⅰ、Ⅱ、Ⅳ和Ⅴ期,P.obliquiloculata的δ13C表现出明显的负偏,而在MIS13期和MIS3期左右,P.obliquiloculata的δ13C表现出明显的正偏。MD06-3047B孔次表层种P.obliquiloculata与表层种G.ruberδ18O的差值反映的温跃层变化具有冰期逐渐变浅,间冰期逐渐变深的特点。表层种G.ruber与次表层种P.obliquiloculata的碳同位素记录,以及底栖种C.wuellerstorfi和表层种P.obliquiloculata的碳同位差值反演的研究区古生产力变化特征为冰期时升高,间冰期时降低。结合MD06-3047B孔的差值结果与西太平洋暖池核心区ODP805站位和赤道东太平洋ODP847站位的差值对比结果,得出热带太平洋在过去70万年来存在类ENSO式的变化特征,冰期时为偏类厄尔尼诺状态,间冰期时为偏类拉尼娜状态,冰消期时为典型的类厄尔尼诺状态。在冰期终止期Ⅰ、Ⅱ、Ⅳ和Ⅴ期,次表层种P.obliquiloculata的碳同位素记录存在极小值事件,说明在这几个冰期终止期来自南极的低δ13C海水到达了西太平洋暖池北部边缘地区。浮游有孔虫Mg/Ca反演的表层水和次表层水的温度,整体趋势上存在冰期间冰期的变化,冰期间冰期温度的变化范围最大达到6℃。
[Abstract]:The MD06-3047B hole on the northern edge of the western Pacific warm Pool was obtained from the Marco Polo 2 IMAGES XIV voyage carried out jointly by China and France. It is located in the Hippenham Plateau of the West Philippines in the eastern part of Luzon Island. The column length is 8.9 m and the water depth is 2510 m. The columnar sample is used to study the paleoceanographic changes in the northern edge of the western Pacific warm pool over the past 700,000 years. The 未 18O of the benthic species C.wuellerstorfi is compared with the standard curve LR04 curve of the oceanic benthic foraminifera by comparing the 未 18O of the benthic species C.wuellerstorfi with the standard curve of the oceanic benthic foraminifera. The age model of MD06-3047B pore was established on the surface of pink G.ruber which appeared about 120,000 years ago. The results show that the MD06-3047B pore consists of 17 oxygen isotope periods. Except for the 未 18O recorded by G.ruber during the MIS14-13 glacial interglacial period, The 未 18O records of the benthic species C.wuellerstorfie, the subsurface species P.obliquiloculata and the surface species G.ruber have obvious characteristics of interglacial variation. The carbon isotopes of the benthic foraminifera C.wuellerstorfi also show obvious characteristics of interglacial variation, and the glacial age is lighter. The carbon isotopic variation of G. ruber during interglacial period is characterized by the gradual weight of glacial period, the gradually lighter carbon isotope of P.obliquiloculata during interglacial period, and the gradual weight of interglacial period during interglacial period. The 未 13C of P.obliquiloculata showed a negative bias, while the 未 13C of P.obliquiloculata in the MIS13 and MIS3 stages showed a significant positive deviation. The difference between the subsurface P.obliquiloculata and G.ruber 未 18O in P.obliquiloculata showed an obvious positive deviation. The variation of thermocline was gradually shallower than that of the G.ruber 未 18O in the subsurface layer of P.obliquooculata, and the variation of 未 13C in P.obliquiloculata was gradually shallower in the glacial period. The carbon isotope records of surface species G.ruber and subsurface species P.obliquiloculata, and the variation of paleoproductivity in the study area by inversion of the carbon isosteric difference between the benthic species C.wuellerstorfi and the surface species P.obliquiloculata are characterized by the increase of glacial age, the characteristics of which are the gradual deepening of the interglacial period. In the interglacial period, the difference between the MD06-3047B hole and the ODP805 station in the central area of the western Pacific warm pool and the ODP847 station in the equatorial eastern Pacific Ocean is compared. It is concluded that the tropical Pacific Ocean has a ENSO like variation in the past 700,000 years. It is a partial El Nino state during the glacial period, a partial La Ni 帽 a-like state in the interglacial period, and a typical El Nino like state during the ice extinction period. At the end of the glacial period I, II, IV and V, the carbon isotope records of the subsurface species P.obliquiloculata have minimal events. The results show that the low 未 13C seawater from the Antarctic reached the northern edge of the western Pacific warm pool during the end of these glacial periods. The temperature of surface water and subsurface water retrieved by planktonic foraminifera (Mg/Ca) shows a variation of interglacial epoch in the whole trend. The temperature range of interglacial epoch is 6 鈩，

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