西北冰洋楚科奇海台08P23孔氧同位素3期以来的古海洋与古气候记录  

PALEOCEANOGRAPHIC AND PALEOCLIMATIC RECORDS OF CORE 08P23 FROM THE CHUKCHI PLATEAU, WESTERN ARCTIC OCEAN,SINCE MIS 3

作　　者：章陶亮 王汝建[1] 陈志华[2] 陈建芳[3] 程振波[2] 孙烨忱[1] 

机构地区：[1]同济大学海洋地质国家重点实验室,上海200092 [2]国家海洋局第一海洋研究所,山东青岛266061 [3]国家海洋局第二海洋研究所,浙江杭州310012

出　　处：《极地研究》2014年第1期46-57,共12页Chinese Journal of Polar Research

基　　金：国家自然科学基金重点项目(41030859);国家自然科学基金中俄合作与交流项目(41211120173);南北极环境综合考察与评估专项(CHINARE2013-03-02;CHINARE2013-04-01);国家海洋局极地考察办公室对外合作支持项目(IC201105);中国地质调查局地质调查工作项目(水[2013]02-013-012)资助

摘　　要：通过中国第三次北极科学考察在北冰洋楚科奇海台采集的08P23孔样品的多项指标分析以及与其他孔的沉积记录综合对比,将08P23孔沉积物初步分为氧同位素3期(MIS 3)-MIS 1的沉积序列。MIS 3以来,楚科奇海台08P23孔可以识别出5个显著的冰筏碎屑(Ice-Rafted Detritus,IRD)事件,分别出现在MIS 2和MIS 3。其中,MIS 3的IRD事件中碎屑碳酸盐岩主要来自于加拿大北极群岛分布广泛的古生代碳酸盐岩露头,MIS 2的IRD事件中碎屑石英可能来源于欧亚大陆边缘。该孔大部分层位浮游有孔虫左旋厚壁新方球虫Neogloboquadrina pachyderma(sinistral)(Nps)的δ18O和δ13C都轻于表层沉积物中的平均值。MIS 3中两个褐色层中偏轻的Nps-δ18O和Nps-δ13C值是由冰融水造成;MIS 1和MIS 3灰色层中偏轻的Nps的δ18O和δ13C值指示海冰形成速率的提高,导致轻同位素卤水的生产和下沉。MIS 2的Nps的δ18O和δ13C值变化趋势相反,是因为温度急剧降低导致Nps-δ18O变重,海水冻结成冰,海气交换明显降低使得Nps-δ13C偏轻。MIS 1和MIS 3的Nps的δ18O和δ13C受到融冰水或轻同位素卤水影响导致同时偏轻。Multi-proxy investigations have been performed on core 08P23, which was collected from the Chukchi Plateau, western Arctic Ocean, during the third Chinese National Arctic Research Expedition. The core was dated to Marine Isotope Stage （MIS） 3 by a combination of AMS 14C dating and regional core correlation. A total of 5 prominent icerafted detritus （IRD） events were recognized in MIS 2 and MIS 3. The IRD events in MIS 3 originated from the vast carbonate rock outcrops of the Canadian Arctic Archipelago and the elastic quartz in MIS 2 may have had a Eurasian origin. Most -δ18O and -δ13 C values of Neogloboquadrina paehyderma （sinistral） （Nps） in core 08P23 are lighter than the average values of the surface sediments. The light Nps-δ18O and -δ13C values in the two brown layers in MIS 1 and MIS 3 resulted from meltwater events, and those in the gray layers in MIS 3 were caused by enhanced sea ice formation. The Nps-δ18O values vary inversely with those of Nps-δ13C in MIS 2, indicating that the study area was covered by thick sea ice or an ice sheet with cold temperatures and little meltwater, which prevented bioproductivity and sea-atmosphere exchange, as well as water mass ventilation. The covarying light values of Nps-δ18O and -δ13C in MIS 1 and MIS 3 resulted from meltwater and/or brine rejection.

关 键 词：西北冰洋 楚科奇海台 氧同位素3期 冰筏碎屑事件 氧碳同位素 水团变化 

分 类 号：P736.2[天文地球—海洋地质]