Recent Summer Climate Recorded in Complex Varved Sediments, Nicolay Lake, Cornwall Island, Nunavut, Canada
Recent Summer Climate Recorded in Complex Varved Sediments, Nicolay Lake, Cornwall Island, Nunavut, Canada
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加拿大努勒维特康沃尔岛尼古拉湖复杂 Varved 沉积物中记录的近期夏季气候
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发表时间：
2006
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通讯作者：
S. Lamoureux
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作者：
G. Hambley;S. Lamoureux
最近（1950-1996）加拿大努勒维特康沃尔岛尼古拉湖（北纬 77°46′ ，西经 94°40′ ）尼古拉湖近端沉积物的记录包含明显的亚年韵律藻。这些亚年节律岩的沉积主要是由于积雪融化，以及夏季主要降水和水下物质消耗事件造成的额外沉积单元。为了评估来自非冰川化流域的水体中包含的潜在水文气候信号，通过描绘每个水体中的初始亚年韵律来估计雪沉积记录。当根据湖中表现出不同沉积物沉积模式的两个阶段将记录分为时间段时，雪峰节律与最近气象站伊萨克森（北纬 78°47′，西经 103°32′）（公元 1950-1962 年和公元 1963-1977 年，分别 r = 0.55 和 r = 0.82）的年累积融化度日 (MDD) 显着相关。对 Resolute（北纬 74°43′，西经 94°59′）数据进行的类似分析得出的相关性稍弱（公元 1950 年至 1962 年，r = 0.60；1963 年至 1994 年，r = 0.59）。与伊萨克森和雷索卢特热记录的强正相关表明沉积物中的古气候信号反映了区域气候条件。值得注意的是，当考虑到整个融化季节时，信号最强；与仪器天气记录的相关性较弱与仅限于融化高峰期或早季融化期的比较有关。我们将此归因于该极地地区整个季节融雪的持续供应以及整个融雪季节运输沉积物的可用性。这些结果表明，尼古拉湖沉积物中存在高分辨率水文气候信号，如果考虑到沉积沉积控制，则可用于古气候重建。
The recent (1950–1996) varve record from the proximal sediments in Nicolay Lake, Cornwall Island, Nunavut, Canada (77°46′ N, 94°40′ W) contains distinct subannual rhythmites. Deposition of these subannual rhythmites is due primarily to nival snow melt, with additional sedimentary units resulting from major summer precipitation and subaqueous mass wasting events. In order to evaluate the potential hydroclimatic signal contained in the varves from the unglacierized catchment, the nival deposition record was estimated by delineating the initial subannual rhythmite within each varve. When the record is split into temporal segments based on two phases that exhibit different sediment deposition patterns in the lake, the nival rhythmites are significantly correlated to annual cumulative melting degree days (MDD) from the nearest weather station Isachsen (78°47′ N, 103°32′ W) (1950–1962 AD and 1963–1977 AD with r = 0.55 and r = 0.82, respectively). A similar analysis with data from Resolute (74°43′ N, 94°59′ W) yields slightly weaker correlations (1950–1962 AD, r = 0.60; 1963–1994, r = 0.59). The strong positive correlation with both the Isachsen and Resolute thermal records suggests that the paleoclimatic signal in the sediments reflects regional climate conditions. Notably, the signal is strongest when the entire melt season is considered; weaker correlations with instrumental weather records are associated with comparisons limited to the peak melt or early season melt periods. We attribute this to the ongoing supply of snowmelt through the season in this polar region and the availability of sediment for transport throughout the melt season. These results indicate that a high resolution hydroclimatic signal is present in the sediments from Nicolay Lake and can be used for paleoclimate reconstruction provided sedimentary depositional controls are taken into account.