摘要
通过对热带碳循环"973"项目于2008年暖池区专题航次采集的KX08-97321-2柱状样(01°25.01′S,157°58.91′E;水深1897m)进行X射线荧光光谱(XRF)扫描以及浮游有孔虫氧同位素测定,结果发现,In(Ba/Ti)和In(Ca/Ti)指示的赤道西太平洋古生产力在过去的370ka以来具有明显的冰期-间冰期变化和岁差周期。间冰期In(Ba/Ti)的平均值比冰期的高13%,说明古生产力冰期低、间冰期高。然而,温跃层替代指标显示该海域温跃层深度的变化不具有简单的冰期-间冰期变化模式,说明温跃层深度不是控制该地区古生产力的主要因素。相反,该地区温跃层的营养物供给受南大洋的影响,可能是影响古生产力的重要原因之一,且可能是高低纬度过程的相互作用导致古生产力变化出现29ka和19ka的周期。
Research on paleo-productivity has received much attention because of the possible link between atmospheric CO2 concentration and organic productivity in the oceans. However, the history of productivity in the Western Equatorial Pacific（ WEP） is poorly known due to the contradictory results of different proxies. Core KX08-97321-2 （ 01 °25.01 ＇S, 157 °58.91 ＇E, water depth 1897m, core length 631 cm） was collected in 2008 during an expedition to the Western Pacific Warm Pool（WPWP）, supported by the 973 program of the Ministry of Science and Technology of China, for the stable isotopic analysis of planktonic foraminifera （Globigerinoides tuber and Pulleniatina obliquiloculata） and the X-ray fluorescence （XRF）core scanning. It has been found that the changes of paleo- productivity in the WEP, which could be indicated by the In （Ba/Ti）and In （Ca/Ti）ratios, displayed clear glacialinterglacial and processional cycles during the last 370ka. The average value of in （Ba/Ti） ratio was 13% higher during interglacial stages than during glacial stages,indicating that the paleo-productivity was high during interglacial stages and vice versa. Moreover,the δ^18 O difference between surface dwelling species G. ruber and thermocline dwelling species P. obliquiloculata, △δ^18 O（p-G）, which was usually interpreted to reflect changes of the thernocline depth, fluctuated around 1.0‰ throughout the past 370ka without a clear glacial-interglacial pattern. Accordingly, the thermocline depth is not a controlling factor on the paleo-productivity in WEP. On the contrary,the nutrient supply of the thermocline in this region,influenced by the Southern Ocean,may be one of the important factors influencing the changes of paleo-productivity. It is inferred that the interaction between the high latitude and low latitude processes probably resulted in the cycles of 29ka and 19ka for the changes of paleo-productivity in WEP.
出处
《第四纪研究》
CAS
CSCD
北大核心
2011年第2期276-283,共8页
Quaternary Sciences
基金
国家重点基础研究发展规划项目(973项目)(批准号:2007CB815901)
国家自然科学基金项目(批准号:40806020和41023004)
大洋协会"十一五"课题(批准号:DY115-01-2-3)联合资助
