摘要
白令海北部陆坡B2-9柱状样中生源组分的研究显示,自MIS 5.3期以来表层生产力指标的粗组分和蛋白石含量呈阶梯状增加,反映表层生产力阶段式的增长.全新世表层生产力达到最高,并且MIS 3.2～2期高,比MIS 5.3～3.3期最低.高有机碳含量对应于高C/N比值,显示有机碳混合来源,不能作为表层生产力的指标.MIS 5.1,3.3～3.2期和全新世高的有机碳含量和C/N比值反映间冰期陆源有机物质输入量的增加.MIS 5.3期至中全新世,不断增加的陆源砂级和粉砂级颗粒组分说明随着气候的逐渐变冷,陆架海冰在不断扩张.伐冰碎屑和碳屑颗粒冰期、间冰段和末次冰消期升高,而间冰期降低,反映冰期白令海陆架海冰扩张和间冰期海冰消融的过程.冰期海冰扩张与北美大陆气候的相互关联,揭示了晚第四纪冰期旋回中自令海海冰扩张及其对全球气候变化的响应.
Quantitative analytic results ot blogenic components m core B2-9 from the northern Bering Sea slope indicate that coarse fraction and opal content, serving as proxies of surface productivity, have increased stepwise since the MIS 5.3, reflecting periodic enhancement in surface productivity. Surface productivity attained its highest level during the Holocene, followed by MIS 3.2 to 2. MIS 5.3 to 3.3 showed the lowest level. High TOC content, together with a high C/N ratio, shows that TOC was deposited from mixed sources and therefore can not be used as a proxy of surface productivity. But high TOC and C/N ratio during MIS 5. 1, 3. 3 to 3.2 and the Holocene reflect that the terrigenous organic matter input increased during interglacial periods. Increases in fine- and silt-grained terrigenous components from M1S 5.3 to the Middle Holocene imply that sea ice on the Bering Sea slope extended continuously in a cooling climate. Ice-rafted （~0. 154 mm quartz and lithic grains） and charcoal detritus increased during glacial, interstadial and the last deglaciation periods, and decreased during interglacial periods, suggesting that sea ice volume on the slope extended and melted, respectively, during glacial and interglacial periods. The extension of sea ice during glacial periods was linked with the climate over North American continent, revealing the responses of sea ice extension in the Bering Sea to global climate change during Late Quaternary glacial and interglacial cycles.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2005年第5期550-558,共9页
Earth Science-Journal of China University of Geosciences
基金
国家重点基础研究发展规划项目(G200078500)
国家自然科学基金项目(Nos.40321603
40276020
40176015)
高等学校全国优秀博士学位论文作者专项项目(No.200126)
高等学校博士学科点专项科研基金项目(No.20040247028).
关键词
表层生产力
筏冰碎屑
海冰扩张
晚第四纪
白令海
surface productivity
ice-rafted detritus
sea ice extension history
Irate Quaternary
Bering Sea.
