Duration and dynamics of the best orbital analogue to the present interglacial
Duration and dynamics of the best orbital analogue to the present interglacial
复制标题
DOI：
10.1130/g36677.1
复制
发表时间：
2015-07-01
期刊：
影响因子：
5.8
通讯作者：
Bassinot, Franck
中科院分区：
文献类型：
--
作者：
Giaccio, Biagio;Regattieri, Eleonora;Bassinot, Franck
过去的轨道类似于现在的间冰期，例如海洋同位素阶段19 c（MIS 19 c，ca。800 ka），可以提供可靠的参考区间，评估的时间和持续时间的全新世及其气候进程中固有的因素。在这里，我们提出了第一个高分辨率的古气候记录MIS 19锚定到一个高精度的40 Ar/39 Ar年代学，从而完全独立于任何先验假设的轨道机制的气候变化。它是基于意大利湖泊沉积物的氧同位素组成，显示810和750万年之间在地中海的轨道到千年尺度的水文变化。我们的记录表明，MIS 19 c间冰期持续了10.8 +/- 3.7 k. y，该卫星的轨道结构与全新世开始以来所经过的时间相当，而且下一次冰期开始时的轨道结构与现在的轨道结构非常相似。以此类推，目前的间冰期应该接近尾声。然而，温室气体浓度在MIS 19冰期开始时显着低于晚全新世，这表明目前的间冰期可能已经延长了温室气体的逐步增加，因为8-6 ka，可能是由于早期的人为干扰植被。
Past orbital analogues to the current interglacial, such as Marine Isotope Stage 19c (MIS 19c, ca. 800 ka), can provide reliable reference intervals for evaluating the timing and the duration of the Holocene and factors inherent in its climatic progression. Here we present the first high-resolution paleoclimatic record for MIS 19 anchored to a high-precision 40Ar/39Ar chronology, thus fully independent of any a priori assumptions on the orbital mechanisms underlying the climatic changes. It is based on the oxygen isotope compositions of Italian lake sediments showing orbital-to millennial-scale hydrological variability over the Mediterranean between 810 and 750 ka. Our record indicates that the MIS 19c interglacial lasted 10.8 +/- 3.7 k.y., comparable to the time elapsed since the onset of the Holocene, and that the orbital configuration at the time of the following glacial inception was very similar to the present one. By analogy, the current interglacial should be close to its end. However, greenhouse gas concentrations at the time of the MIS 19 glacial inception were significantly lower than those of the late Holocene, suggesting that the current interglacial could have already been prolonged by the progressive increase of the greenhouse gases since 8-6 ka, possibly due to early anthropogenic disturbance of vegetation.