Holocene Hydroclimatic Reorganizations in Northwest Canada Inferred From Lacustrine Carbonate Oxygen Isotopes
Holocene Hydroclimatic Reorganizations in Northwest Canada Inferred From Lacustrine Carbonate Oxygen Isotopes
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DOI：
10.1029/2021gl092948
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发表时间：
2021-08
影响因子：
5.2
通讯作者：
G. Lasher;M. Abbott;L. Anderson;L. Yasarer;M. Rosenmeier;B. Finney
中科院分区：
文献类型：
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作者：
G. Lasher;M. Abbott;L. Anderson;L. Yasarer;M. Rosenmeier;B. Finney
斯夸加湖介形虫和自生方解石的亚百年氧（δ 18 O）同位素为加拿大西北部内陆地区的水文气候极端和一系列冰后期气候系统重组提供了证据。自生方解石的δ 18 O值介于−16‰至−21‰之间，目前与现代湖水和年降水量值相似。介形虫δ 18 O记录与方解石的趋势接近，偏移量为+1.7 ± 0.6‰。在11 ka BP（kaBP = 1950年之前的数千年），较高的δ 18 O值反映了剩余冰盖对水分可用性的影响导致的降水-蒸发（P-E）平衡下降。δ 18 O值在1.8kaBP之前呈下降趋势，反映了气候条件向湿润方向的转变和大气环流的重组。上个千年和现代相对干燥，但不像全新世早期那样干燥。北太平洋气候动态仍然是加拿大西北部整个全新世P−E平衡的重要驱动力。
Sub‐centennial oxygen (δ18O) isotopes of ostracod and authigenic calcite from Squanga Lake provides evidence of hydroclimatic extremes and a series of post‐glacial climate system reorganizations for the interior region of northwest Canada. Authigenic calcite δ18O values range from −16‰ to −21‰ and are presently similar to modern lake water and annual precipitation values. Ostracod δ18O record near identical trends with calcite, offset by +1.7 ± 0.6‰. At 11 ka BP (kaBP = thousands of years before 1950), higher δ18O values reflect decreased precipitation−evaporation (P−E) balance from residual ice sheet influences on moisture availability. A trend to lower δ18O values until ∼8 ka BP reflects a shift to wetter conditions, and reorganization of atmospheric circulation. The last millennium and modern era are relatively dry, though not as dry as the early Holocene extreme. North Pacific climate dynamics remained an important driver of P−E balance in northwest Canada throughout the Holocene.