Frequency and dynamics of millennial-scale variability during Marine Isotope Stage 19: Insights from the Sulmona Basin (central Italy)
Frequency and dynamics of millennial-scale variability during Marine Isotope Stage 19: Insights from the Sulmona Basin (central Italy)
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DOI：
10.1016/j.quascirev.2019.04.024
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发表时间：
2019-06
影响因子：
4
通讯作者：
E. Regattieri;B. Giaccio;G. Mannella;G. Zanchetta;S. Nomade;A. Tognarelli;N. Perchiazzi;H. Vogel;C. Boschi;R. Drysdale;B. Wagner;M. Gemelli;Polichronis Tzedakis
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作者：
E. Regattieri;B. Giaccio;G. Mannella;G. Zanchetta;S. Nomade;A. Tognarelli;N. Perchiazzi;H. Vogel;C. Boschi;R. Drysdale;B. Wagner;M. Gemelli;Polichronis Tzedakis
在过去的间冰期中，海洋同位素阶段19特别令人感兴趣，因为它的轨道几何形状与现在的间冰期非常相似。在这里，我们提供了一个高分辨率(亚百年)的多重代理记录，涵盖了大约790-770ka的时间间隔，即间冰期MIS19c和随后的MIS19b的冰川开始，来自苏尔莫纳盆地(意大利中部)的湖泊沉积序列。该记录具有基于六个火山灰层的辐射测年的独立年代学，由此产生的年龄模型的平均相关不确定度为±2.6KYR。沉积物地球化学和矿物学的变化可以用过去的水文和温度变化来解释。很好地表达了几个千年和亚千年降水减少的事件。与北大西洋中纬度和亚极地的大陆和海洋记录进行比较表明，观测到的事件有广泛的空间表达。间冰期内发生的事件与伊比利亚边缘海洋指标的变化没有明显的联系，尽管可以确认与北大西洋次极地记录的相似之处，并初步将其与当地水文变化联系在一起，后者的下游效应因大气环流的变化而放大。在冰川开始期间，苏莫纳记录的变化与北大西洋记录的变化是一致的，更干燥的事件可能与融水导致的AOC减弱的间隔有关。与全新世的8.2ka事件类似，约785.6 ka的事件也可能反映了由残余冰盖的淡水排放和暴发的洪水引起的海洋变化。
Among past interglacial periods, Marine Isotope Stage (MIS) 19 is particularly interesting because its orbital geometry is very similar to that of the present interglacial. Here we present a high-resolution (sub-centennial) multiproxy record covering the ca. 790-770 ka interval, i.e. the interglacial MIS 19c and the ensuing glacial inception of MIS 19b, from a lacustrine sediment sequence retrieved from the Sulmona Basin (central Italy). The record has an independent chronology based on radiometric dating of six volcanic ash layers, and the resulting age model has a mean associated uncertainty of ±2.6 kyr. Variations in sediment geochemistry and mineralogy are interpreted in terms of past hydrological and temperature changes. Several millennial and sub-millennial events of reduced precipitation are well expressed. Comparisons with continental and marine records from the mid-latitude and sub-polar North Atlantic suggest a broad spatial expression for the observed events. Events occurring within the interglacial are not clearly associated with changes in marine proxies in the Iberian Margin, although similarities with the record from the sub-polar North Atlantic can be recognized and tentatively linked to changes in local hydrography having a downstream effect amplified by changes in atmospheric circulation. During the glacial inception, changes in the Sulmona record are coherent with changes in North Atlantic records, with drier events likely associated with meltwater-induced intervals of AMOC weakening. An event at ca. 785.6 ka may also reflect oceanic changes caused by freshwater discharges from residual ice-sheets and an outburst flood, similar to the 8.2 ka event in the Holocene.