Holocene and Last Interglacial climate of the Faroe Islands from sedimentary plant wax hydrogen and carbon isotopes
Holocene and Last Interglacial climate of the Faroe Islands from sedimentary plant wax hydrogen and carbon isotopes
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DOI：
10.1016/j.quascirev.2019.105930
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发表时间：
2019-11-01
影响因子：
4
通讯作者：
Bradley, Raymond
中科院分区：
文献类型：
--
作者：
Curtin, Lorelei;D'Andrea, William J.;Bradley, Raymond
末次间冰期（英语：Last Interglacial period）是地球最近的全球变暖时期，在某些方面类似于预测未来的全球变暖。然而，问题仍然存在于北大西洋LIG期间的气候状态，这是一个对海洋和大气环流变化极其敏感的区域。在这里，我们提出了氢和碳同位素（三角洲D和三角洲C-13）记录从一套植物蜡生物标志物保存在全新世和LIG湖沉积物从北大西洋法罗群岛和解释他们作为定性代理温度和水文气候变化。这些数据用于直接比较LIG和全新世气候使用相同的代理方法从相同的陆地位置。测量多种类型的蜡的多种同位素阐明了同源植物蜡的来源。我们推断，在这些沉积档案中的长链正构烷烃（C-27-C-33）和中链正构烷烃（C-23-C-25）的三角洲D值分别反映叶水和湖水三角洲D值，而长链（C-28-C-30）和中链正构烷酸（C-24-C-26）的三角洲D值主要代表湖水三角洲D值。植物蜡推断的三角洲D值的降水在全新世早期（10,100至8,200卡年BP）是类似的千分之三十五比晚全新世的值更积极，并在全新世下降。三角洲D推断的水文变化和三角洲C-13推断的植物水分利用效率都表明，法罗群岛在整个全新世变得干燥。从LIG植物蜡测量结果的比较表明，晚LIG在法罗群岛的水文相似的早至中期全新世（8,200至4,000卡年BP），丰富的降水同位素和减少蒸散指示一个温暖，潮湿的环境。(C)2019爱思唯尔有限公司版权所有。
The Last Interglacial period (LIG) is Earth's most recent globally warm period and is analogous in some ways to projected future global warming. However, questions remain regarding the state of the climate during the LIG in the North Atlantic, a region that is extremely sensitive to changes in oceanic and atmospheric circulation. Here, we present hydrogen and carbon isotope (delta D and delta C-13) records from a suite of plant wax biomarkers preserved in Holocene and LIG lacustrine sediments from the North Atlantic Faroe Islands and interpret them as qualitative proxies for temperature and hydroclimate variability. These data are used to directly compare LIG and Holocene climate using the same proxy approaches from the same terrestrial location. Measuring multiple isotopes on multiple types of waxes elucidates the sources of homologous plant waxes. We deduce that the delta D values of long-chain n-alkanes (C-27-C-33) and mid-chain n-alkanes (C-23-C-25) in these sedimentary archives reflect leaf water and lake water delta D values, respectively, while the delta D values for both long-chain (C-28-C-30) and mid-chain n-alkanoic acids (C-24-C-26) primarily represent lake water delta D values. Plant wax-inferred delta D values of precipitation during the early Holocene (10,100 to 8,200 cal yr BP) are similar to 35 parts per thousand more positive than late Holocene values, and decline over the Holocene. delta D-inferred hydrologic change and delta C-13 -inferred plant water use efficiency both indicate that the Faroe Islands became drier throughout the Holocene. Comparison with measurements from LIG plant waxes indicates that late LIG in the Faroe Islands was hydrologically similar to the early-to mid-Holocene (8,200 to 4,000 cal yr BP), with enriched precipitation isotopes and reduced evapotranspiration indicating a warmer, wetter environment. (C) 2019 Elsevier Ltd. All rights reserved.