Last deglaciation and Holocene environmental change at high altitude in the Pyrenees: the geochemical and paleomagnetic record from Marboré Lake (N Spain)
Last deglaciation and Holocene environmental change at high altitude in the Pyrenees: the geochemical and paleomagnetic record from Marboré Lake (N Spain)
复制标题
DOI：
10.1007/s10933-017-0013-9
复制
发表时间：
2018-03
影响因子：
2.1
通讯作者：
B. Oliva‐Urcia;A. Moreno;M. Leunda;B. Valero-Garcés;P. González‐sampériz;G. Gil‐Romera;M. Mata
中科院分区：
文献类型：
--
作者：
B. Oliva‐Urcia;A. Moreno;M. Leunda;B. Valero-Garcés;P. González‐sampériz;G. Gil‐Romera;M. Mata
摘要/生物谷学报/生物谷学报/生物谷学报/生物谷学报/生物谷学报/生物谷学报沉积层序由毫米至厘米厚的韵律岩组成，韵律岩由较细的灰色纹层和较粗的含碳酸盐纹层组成，在整个层序中以不同的模式排列。较细的层状沉积物被解释为在主要被冰覆盖的条件下的沉积，而较粗的含碳酸盐的沉积物反映了较高径流的时期。该年龄模型基于1314C年代和用210pb和137cs评估的储层效应，与已知的比利牛斯山脉植被同步变化一致。GI-1 （14.6 ~ 12.8 cal ka BP， Bølling/Allerød期）、10.4 ~ 8.2 cal ka BP（早全新世）、7.5 ~ 5.2 cal ka BP（中全新世）和中世纪气候异常（公元900 ~ 1300年）等较暖期以生产力峰值和较高的碳酸盐保存为特征。GS-1 （12.8 ~ 11.7 cal ka BP）、新冰川期（约5.2 ~ 3.5 cal ka BP）和小冰期（近400年）等较冷时期的沉积显示出细纹层的增加。整个剖面中磁铁矿的存在表明马尔博尔湖自形成以来一直保持着主要的氧条件。然而，从3.5 cal ka BP到现在，磁性质的变化和磁铁矿的增加表明，在过去的几千年里，湖底的氧气环境更加丰富。罗马和现代沉积物中Pb浓度峰值的出现，说明了重金属沉积的全球分布，甚至进入高山湖泊。
Sedimentological, geochemical and magnetic data in a ~ 7-m sequence from Marboré Lake (2612 m asl, central Pyrenees) provide information about environmental variability since the last glacier retreat (14.6 cal ka BP) in high-altitude Pyrenean environments. The sediment sequence is composed of millimeter- to centimeter-thick rhythmites made of finer greyish laminae and coarser-grain, carbonate-bearing laminae arranged in varied patterns throughout the sequence. Finer laminae are interpreted as deposition during periods of predominantly ice-covered conditions, whereas coarser, carbonate-bearing sediments reflect periods of higher runoff. The age model, based on 1314C dates and a reservoir effect assessed with210Pb and137Cs, is coherent with known synchronous vegetation changes across the Pyrenees. Warmer intervals such as GI-1 (14.6–12.8 cal ka BP, Bølling/Allerød period), 10.4–8.2 cal ka BP in the Early Holocene, 7.5–5.2 cal ka BP in the Mid Holocene and the Medieval Climate Anomaly (AD 900–1300), are characterized by peaks in productivity and higher carbonate preservation. Deposition during colder periods such as GS-1 (12.8–11.7 cal ka BP), the Neoglacial (ca. 5.2–3.5 cal ka BP) and the Little Ice Age (last 400 years) show an increase in finer laminae. The presence of magnetite throughout the whole section suggests that Marboré Lake maintained predominantly oxic conditions since its formation. Changes in magnetic properties and the increase in magnetite from 3.5 cal ka BP to present, however, indicate a more oxic environment at the lake bottom during the last few millennia. The occurrence of Pb concentration peaks in sediments of Roman and modern age demonstrates the global distribution of heavy metal deposition, even into high-mountain lakes.