北极新奥尔松古海鸟粪土层的识别

对采自北极新奥尔松(Ny-lesund)一级海岸阶地上的海蚀凹槽沉积剖面进行沉积岩相学、同位素地球化学和元素地球化学研究,结果显示该剖面的70-118 cm段显著受到了海鸟粪沉积的影响,为含贝壳的海鸟粪土沉积层。该段粪土沉积层中大多数元素的浓度随深度表现出明显的波动特征,其中TOC、TN、Se、Sr、CaO、Pb、As、Zn等元素含量在深度剖面上表现出较为一致的垂向变化趋势。对粪土层的元素地球化学数据进行了聚类分析,结果表明在浓度剖面上具有较好协同关系的上述元素组合与海鸟粪有机质的输入密切相关,这些具有显著地球化学性质差异的元素共生组合是北极新奥尔松粪土沉积层的生物地球化学组合的标型特征,它们的含量变化主要受控于海鸟粪对沉积物的影响程度。海鸟粪土生物地球化学标型组合特征的识别为进一步研究该地区12-4 ka B.P.的海鸟生态系统和气候演化记录提供了科学基础。

IDENTIFICATION OF SEABIRD-DROPPING AMENDED SEDIMENTS IN PALAEO-NOTCHES OF NY-ALESUND, SVALBARD, ARCTIC

We collected a 118 cm long and well-preserved sediment profile in palaeo-notches from the first strandflat of Ny-lesund(78°55′N,11°56′E),Svalbard,Arctic,and performed multiple sedimentological analyses,including the lithological characteristics of the sediments,the carbon and nitrogen isotopic compositions and chemical element contents.The results showed that the 70—118 cm layer of the sediments was significantly amended by seabird-dropping.The concentrations of TOC、TN、TS、Se、Sr、CaO、As、Pb、Zn in the sediments are notably enriched,they are significantly correlated with each other,and they have a consistent pattern of change versus depth.These elements are good biomarkers for seabirddropping and population.These results could lay the groundwork for the reconstruction of palaeoclimate and the seabird occupation history between 12 ka B.P.and 4 ka B.P.in Ny-lesund,Svalbard,Arctic.