印-太暖池区全新世Mg/Ca温度转换中的盐度因素  

Salinity effect on Holocene Mg/Ca-temperature estimation from the Indo-Pacific warm-pool sediment samples

作　　者：王文洁[1] 徐建[1] 

机构地区：[1]西北大学新生代地质与环境研究所、大陆动力学国家重点实验室、地质学系,陕西西安710069

出　　处：《热带海洋学报》2014年第2期94-100,共7页Journal of Tropical Oceanography

基　　金：高等学校博士学科点专项科研基金(20096101120025);国家自然科学基金项目(40906032、41176044);大陆动力学国家重点实验室自主研究课题(BJ11052)

摘　　要：有孔虫Mg/Ca温度计是古海洋学研究中恢复古温度的重要手段之一。然而,越来越多的研究表明,Mg/Ca温度计的准确性受多种因素的影响,特别是盐度的控制十分重要。文章实测并搜集整理了印-太暖池地区全新世(大约11kaB.P.以来)1000余个浮游有孔虫Mg/Ca比值数据,分别利用包含和不包含盐度信息的两个常用转换方程求取了古海水温度,并将二者进行了对比,旨在探讨盐度因素对Mg/Ca温度计的影响。结果显示,在表层水温大约28℃以下,两个方程获得的结果几乎一致,平均差异为0.07℃;在表层水温28℃以上,二者平均相差大约1℃。此外,表层海水盐度越低,包含盐度信息的转换方程获得的古海水氧同位素的值越大。上述结果揭示盐度对该地区有孔虫Mg/Ca比值的影响效应不明显。Foraminiferal Mg/Ca-thermometer is one of the key methods in reconstructing past ocean temperatures. Increasing evidence, however, revealed that precision of Mg/Ca-thermometer is influenced by various factors in addition to seawater temperature. Of these factors, salinity is in particular highlighted. This study measured and collected an amount of more than one thousand Holocene （since about 11 ka B.P.） foraminiferal Mg/Ca ratios from sediment cores recovered from the Indo-Pacific warm pool. These Mg/Ca ratios were converted into temperatures using two conventional equations, with and without salinity involved. Estimated temperatures were then compared to reveal salinity effects on Mg/Ca-thermometer used for samples from the Indo-Pacific warm-pool region. It is shown that values resulted from the two equations are very similar, with a difference of 0.07℃on average in the case that the estimated temperature is lower than 28℃. In contrast, difference is up to 1℃ when the estimated temperature is higher than 28℃. Moreover, it is also revealed that less saline water and larger seawater oxygen isotope were estimated using the equation involving salinity. These findings imply that salinity likely had little influence on foraminiferal Mg/Ca in this region.

关 键 词：表层海水温度 MgCa温度计 印-太暖池 全新世 

分 类 号：P736.4[天文地球—海洋地质]