Five thousand years of sediment transfer in a high arctic watershed recorded in annually laminated sediments from Lower Murray Lake, Ellesmere Island, Nunavut, Canada
Five thousand years of sediment transfer in a high arctic watershed recorded in annually laminated sediments from Lower Murray Lake, Ellesmere Island, Nunavut, Canada
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DOI：
10.1007/s10933-008-9252-0
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发表时间：
2009-01-01
影响因子：
2.1
通讯作者：
Francus, Pierre
中科院分区：
文献类型：
--
作者：
Cook, Timothy L.;Bradley, Raymond S.;Francus, Pierre
加拿大努纳武特地区（北纬81度21 '，西经69度32'）北方埃尔斯米尔岛下默里湖的沉积物中含有每年一次的纹层（纹层），提供了过去5000多年来沉积物积累的记录。根据纹层厚度和沉积物体积密度的测量，估计了年质量积累。下墨累湖质量积累与仪器气候数据，长期记录的气候强迫机制和其他区域古气候记录的比较表明，湖泊沉积与区域融化季节温度驱动的辐射强迫呈正相关。温度重建表明，最近的温度比小冰期期间观察到的最低温度高出2.6A摄氏度，过去5200年的最高温度比现代值高出0.6A摄氏度，而公元前2900年左右观察到的最低温度比最近的条件低3.5A摄氏度。最近的气温是自14世纪以来最热的，但类似的条件存在于类似的4000-1000年前的间歇性。一个高度稳定的沉积模式，在整个记录期间支持使用的年度质量积累在下墨累湖作为一个可靠的代理指标，在过去的当地气候条件。
Sediments in Lower Murray Lake, northern Ellesmere Island, Nunavut Canada (81A degrees 21'A N, 69A degrees 32'A W) contain annual laminations (varves) that provide a record of sediment accumulation through the past 5000+ years. Annual mass accumulation was estimated based on measurements of varve thickness and sediment bulk density. Comparison of Lower Murray Lake mass accumulation with instrumental climate data, long-term records of climatic forcing mechanisms and other regional paleoclimate records suggests that lake sedimentation is positively correlated with regional melt season temperatures driven by radiative forcing. The temperature reconstruction suggests that recent temperatures are similar to 2.6A degrees C higher than minimum temperatures observed during the Little Ice Age, maximum temperatures during the past 5200 years exceeded modern values by similar to 0.6A degrees C, and that minimum temperatures observed approximately 2900 varve years BC were similar to 3.5A degrees C colder than recent conditions. Recent temperatures were the warmest since the fourteenth century, but similar conditions existed intermittently during the period spanning similar to 4000-1000 varve years ago. A highly stable pattern of sedimentation throughout the period of record supports the use of annual mass accumulation in Lower Murray Lake as a reliable proxy indicator of local climatic conditions in the past.