白令海DSDP188站氧同位素3期以来的古海洋与古气候记录

PALEOCEANOGRAPHIC AND PALEOCLIMATIC RECORDS FROM DSDP SITE 188 IN THE BERING SEA SINCE MARINE ISOTOPIC STAGE 3

  • 摘要: 白令海南部DSDP188站沉积物生源组分分析显示,该地区表层生产力在MIS3早、晚期(3.3和3.1)以及MIS2期增加,而其他时期表层生产力相应降低,并且表层生产力的变化没有显示明显的冰期与间冰期旋回。沉积物的C/N比值反映了有机碳的混合来源,说明该地区表层生产力可能受陆源营养物质输入的影响。该站位沉积物的非生源组分分析显示,MIS3早、晚期陆源物质输入量增加,反映洋流加强和气候变化。MIS2出现两次陆源物质输入量的增加,显示了洋流和气候的波动。MIS3和末次冰消期碳屑丰度增加,但MIS2降低,指示MIS3和MIS1陆地天然火灾概率大,而MIS2天然火灾概率低,反映间冰期比冰期更容易发生天然火灾。

     

    Abstract: Quantitative analytic results of the biogenic components at DSDP Site 188 on the west edge of Bowers Ridge in the southern Bering Sea indicate that the opal content, serving as proxies of surface productivity, increased during the early and late MIS 3 and late MIS 2, reflecting the enhancement in surface productivity. However, the surface productivity deceased at other intervals and its change did not respond to the glacial-interglacial cycles. C/N ratio in sediments, indicating the mixed source, reflects the possible influence of terrigenous organic matter input on the surface productivity. The results of non-biogenic components at DSDP Site 188 show that the terrigenous detritus input increased during early and late MIS 3 and MIS 2, displaying the evident fluctuation of current and climate. The charcoal detritus increased during MIS 3 and the last deglaciation and decreased during the MIS 2, suggesting probability of natural fires higher during interglacial periods than during glacial periods, which linked with the climate over the North American Continent and responded to global climate change during late Quaternary glacial and interglacial cycles.

     

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