Striking similarities in temporal changes to spring sea ice occurrence across the central Canadian Arctic Archipelago over the last 7000 years
Striking similarities in temporal changes to spring sea ice occurrence across the central Canadian Arctic Archipelago over the last 7000 years
复制标题
DOI：
10.1016/j.quascirev.2010.06.041
复制
发表时间：
2010-12
影响因子：
4
通讯作者：
S. Belt;Lindsay L. Vare;G. Massé;G. Massé;H. Manners;J. C. Price;S. Maclachlan;J. Andrews;S. Schmidt
中科院分区：
文献类型：
--
作者：
S. Belt;Lindsay L. Vare;G. Massé;G. Massé;H. Manners;J. C. Price;S. Maclachlan;J. Andrews;S. Schmidt
通过对2005年获得的两个海洋沉积物柱塞岩心中海冰硅藻衍生生物标志物ip25的定量分析，确定了加拿大北极群岛（CAA）维多利亚海峡（ARC-4）和迪斯海峡（ARC-5） 7000年的春季海冰记录。ARC-4和ARC-5岩心的年代学采用大型底栖动物化石的14c AMS数据和磁化率测量相结合的方法确定。通过与相应盒芯的化学和物理参数相匹配，估计了活塞芯顶部的年龄。这些分析表明，虽然ARC-4活塞核心的顶部估计基本上是现代的（大约60万年BP），但ARC-5活塞核心似乎没有几百年的沉积物。两个岩芯的ip25通量的下核变化是根据春季海冰发生的变化来解释的，维多利亚海峡、迪斯海峡和巴罗海峡（以前报道过）的ip25通量剖面之间的相关性在50年和100年分辨率下都显示出统计学意义。ip25数据表明，在该记录的早期（约7.0-3.0 cal kyr BP）和晚全新世的部分时间（约1.5-0.8 cal kyr BP），春季海冰的发生率较低，特别是在两个较低纬度的研究地点。相比之下，在约3.0 ~ 1.5 calyr BP和约800 calyr BP之后出现了更多的春季海冰。晚全新世两个时期的春季海冰出现量依次减少和增加，与中暖期和小冰期基本一致。ip25数据还补充了粒度和矿物学数据，尽管这些数据可能反映了研究地点海平面的变化。ip25数据还与以前基于代理的古海冰和古气候测定进行了比较，包括基于弓头鲸遗骸和恐龙囊组合的测定。代理数据的空间一致性表明，春季海冰的出现在3 calkyr BP左右增加，这为中部地区全新世热极大期的结束提供了一个潜在的有用基准。
A 7000 year spring sea ice record for Victoria Strait (ARC-4) and Dease Strait (ARC-5) in the Canadian Arctic Archipelago (CAA) has been determined by quantification of the sea ice diatom-derived biomarker IP25in two marine sediment piston cores obtained in 2005. The chronologies of the ARC-4 and ARC-5 cores were determined using a combination of14C AMS dates obtained from macrobenthic fossils and magnetic susceptibility measurements. The ages of the tops of the piston cores were estimated by matching chemical and physical parameters with those obtained from corresponding box cores. These analyses revealed that, while the top of the ARC-4 piston core was estimated to be essentially modern (ca. 60 cal yr BP), a few hundred years of sediment appeared to be absent from the ARC-5 piston core. Downcore changes to IP25fluxes for both cores were interpreted in terms of variations in spring sea ice occurrence, and correlations between the individual IP25flux profiles for Victoria Strait, Dease Strait and Barrow Strait (reported previously) were shown to be statistically significant at both 50 and 100-year resolutions. The IP25data indicate lower spring sea ice occurrences during the early part of the record (ca. 7.0–3.0 cal kyr BP) and for parts of the late Holocene (ca. 1.5–0.8 cal kyr BP), especially for the two lower latitude study locations. In contrast, higher spring sea ice occurrences existed during ca. 3.0–1.5 cal kyr BP and after ca. 800 cal yr BP. The observation of, consecutively, lower and higher spring sea ice occurrence during two periods of the late Holocene, coincides broadly with the Medieval Warm Period and Little Ice Age epochs, respectively. The IP25data are complemented by particle size and mineralogical data, although these may alternatively reflect changes in sea level at the study sites. The IP25data are also compared to previous proxy-based determinations of palaeo sea ice and palaeoclimate for the CAA, including those based on bowhead whale remains and dinocyst assemblages. The spatial consistency in the proxy data which, most notably, indicates an increase in spring sea ice occurrence around 3 cal kyr BP, provides a potentially useful benchmark for the termination of the Holocene Thermal Maximum for the central CAA.