Diatom records and tephra mineralogy in pingo deposits of Seward Peninsula, Alaska
Diatom records and tephra mineralogy in pingo deposits of Seward Peninsula, Alaska
复制标题
阿拉斯加苏厄德半岛平戈沉积物中的硅藻记录和火山灰矿物学
DOI：
10.1016/j.palaeo.2017.04.006
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
G. Grosse
中科院分区：
文献类型：
--
作者：
O. Palagushkina;S. Wetterich;B. Biskaborn;L. Nazarova;Lutz Schirrmeister;J. Lenz;G. Schwamborn;G. Grosse
亚北极和北极陆地的大片地区被永久冻土覆盖。因此，景观演化很大程度上受气候驱动的冰缘过程控制。冻土对第四纪晚期温暖和寒冷阶段的响应保留在永久冻土序列中，并且可以通过多代理古环境方法推断。在这里，我们分析了 Kit-1 pingo 永久冻土序列中保存的放射性碳测年威斯康星中期和全新世湖泊沉积物，并结合苏厄德半岛（阿拉斯加西北）九个现代水体的水和表面沉积物样本，以重建热喀斯特动力学并确定控制水生生态系统变异的主要非生物因素。我们的方法包括硅藻分类分析以及去趋势对应分析 (DCA) 和冗余分析 (RDA)。我们的结果表明，硅藻化石记录反映了自大约 4214C kyr BP 以来的热喀斯特湖演替。威斯康星州际公路中期、威斯康星州晚期和全新世早期的不同热岩溶湖阶段反映了硅藻丰度、多样性和生态的变化。我们结合周围池塘的现代硅藻数据以及来自平戈序列的现有微古生物学、沉积学和矿物学数据来解释硅藻化石组合的分类变化。基于硅藻的湖水定量重建 рН 表明了威斯康星州中期到全新世早期湖泊环境的变化。矿物学分析表明存在火山灰沉降物及其对硅藻化石群落的影响。我们对现代硅藻群落和化石硅藻群落的比较表明，现代多边形池塘与热岩溶湖泊相应的初始（浅水）发育阶段具有最高的植物区系相似性。我们得出的结论是，研究区域的威斯康星州中部热岩溶过程可能是在相对温暖的间质气候条件下建立的，伴随着由于接近海岸而导致的降水增加，而大陆性仍然较高，因此季节性温度梯度较高，导致白令海峡中部地区出现温暖的夏季。
Vast areas of the terrestrial Subarctic and Arctic are underlain by permafrost. Landscape evolution is therefore largely controlled by climate-driven periglacial processes. The response of the frozen ground to late Quaternary warm and cold stages is preserved in permafrost sequences, and deducible by multi-proxy palaeoenvironmental approaches. Here, we analyse radiocarbon-dated mid-Wisconsin Interstadial and Holocene lacustrine deposits preserved in the Kit-1 pingo permafrost sequence combined with water and surface sediment samples from nine modern water bodies on Seward Peninsula (NW Alaska) to reconstruct thermokarst dynamics and determine major abiotic factors that controlled the aquatic ecosystem variability. Our methods comprise taxonomical diatom analyses as well as Detrended Correspondence Analysis (DCA) and Redundancy Analysis (RDA). Our results show, that the fossil diatom record reflects thermokarst lake succession since about 4214C kyr BP. Different thermokarst lake stages during the mid-Wisconsin Interstadial, the late Wisconsin and the early Holocene are mirrored by changes in diatom abundance, diversity, and ecology. We interpret the taxonomical changes in the fossil diatom assemblages in combination with both modern diatom data from surrounding ponds and existing micropalaeontological, sedimentological and mineralogical data from the pingo sequence. A diatom-based quantitative reconstruction of lake water рН indicates changing lake environments during mid-Wisconsin to early Holocene stages. Mineralogical analyses indicate presence of tephra fallout and its impact on fossil diatom communities. Our comparison of modern and fossil diatom communities shows the highest floristic similarity of modern polygon ponds to the corresponding initial (shallow water) development stages of thermokarst lakes. We conclude, that mid-Wisconsin thermokarst processes in the study area could establish during relatively warm interstadial climate conditions accompanied by increased precipitation due to approaching coasts, while still high continentality and hence high seasonal temperature gradients led to warm summers in the central part of Beringia.
登录
查看更多内容
影响因子：
4
作者：
S. Wetterich;V. Tumskoy;N. Rudaya;A. Andreev;T. Opel;H. Meyer;Lutz Schirrmeister;Matthias Hüls
通讯作者：
S. Wetterich;V. Tumskoy;N. Rudaya;A. Andreev;T. Opel;H. Meyer;Lutz Schirrmeister;Matthias Hüls
影响因子：
2.2
作者：
Nazarova, Larisa;Bleibtreu, Annette;Diekmann, Bernhard
通讯作者：
Diekmann, Bernhard
影响因子：
4
作者：
Biskaborn, B. K.;Subetto, D. A.;Diekmann, B.
通讯作者：
Diekmann, B.
影响因子：
3.9
作者：
L. Nazarova;A. Self;S. Brooks;M. Hardenbroek;U. Herzschuh;B. Diekmann
通讯作者：
L. Nazarova;A. Self;S. Brooks;M. Hardenbroek;U. Herzschuh;B. Diekmann
气候相关因素对阿纳巴尔河流域北极湖泊浮游动物群落形成的影响分析
影响因子：
0.8
作者：
Frolova;Nazaroa;Pestryakova;Herzschuh
通讯作者：
Herzschuh