Abstract：
Iberian lacustrine sediments are a valuable archive to document environmental changes since the last glacial termination, seen as key for anticipating future climate/environmental changes and their far-reaching implications for generations to come. Herein, multi-proxy-based indicators of a mountain lake record from Serra da Estrela were used to reconstruct atmospheric (in)fluxes and associated climatic/environmental changes over the last ∼13.5 ka. Depositions of long-range transported dust (likely from the Sahara) and halogens (primarily derived from seawater) were higher for the pre-Holocene, particularly in the late Bølling-Allerød-Younger Dryas period, compared to the Holocene. This synchronous increase could be related to a recognized dust-laden atmosphere, along with the combined effect of (i) an earlier proposed effective transport of Sahara dust for higher latitudes during cold periods and (ii) the progressive Polar Front expansion southwards, with the amplification of halogen activation reactions in lower latitudes due to greater closeness to snow/sea ice (halide-laden) surfaces. Additionally, the orographic blocking of Serra da Estrela may have played a critical role in increasing precipitation of Atlantic origin at higher altitudes, with the presence of snow prompting physical and chemical processes involving halogen species. In the Late Holocene, the dust proxy records highlighted two periods of enhanced input to Lake Peixão, the first (∼3.5-2.7 ka BP) after the end of the last African Humid Period and the second, from the 19th century onwards, agreeing with the advent of commercial agriculture, and human contribution to land degradation and dust emission in the Sahara/Sahel region. The oceanic imprints throughout the Holocene matched well with North Atlantic rapid climatic changes that, in turn, coincided with ice-rafted debris or Bond events and other records of increased storminess for the European coasts. Positive parallel peaks in halogens were found in recent times, probably connected to fire extinction by halogenated alkanes and roadway de-icing.
摘要：
伊比利亚湖相沉积物是记录自上次冰川终止以来环境变化的宝贵档案，被视为预测未来气候/环境变化及其对后代的深远影响的关键。在这里，来自SerradaEstrela的山区湖泊记录的基于多代理的指标用于重建最后一个〜13.5ka的大气（in）通量和相关的气候/环境变化。在全新世之前，远距离运输的尘埃（可能来自撒哈拉沙漠）和卤素（主要来自海水）的沉积量较高，特别是在Bølling-Allerød-YoungerDryas晚期，与全新世相比。这种同步增加可能与公认的多尘大气有关，连同（i）较早提出的在寒冷时期为高纬度地区有效运输撒哈拉沙漠尘埃的综合作用，以及（ii）渐进的极地前线向南扩展，由于与雪/海冰（含卤化物）表面的更紧密，在低纬度地区卤素活化反应的放大。此外,SerradaEstrela的地形阻塞可能在增加海拔较高的大西洋起源的降水中发挥了关键作用，雪的存在促使涉及卤素物种的物理和化学过程。在全新世晚期,灰尘代理记录突出显示了两个时期对Peixão湖的增强投入，上一个非洲湿润期结束后的第一个(~3.5-2.7kaBP)和第二个,从19世纪开始,同意商业农业的出现，以及人类对撒哈拉/萨赫勒地区土地退化和粉尘排放的贡献。整个全新世的海洋印记与北大西洋的快速气候变化非常吻合，反过来,恰逢浮冰碎片或邦德事件以及其他欧洲海岸暴风雨增加的记录。最近发现了卤素的正平行峰，可能与卤化烷烃和道路除冰的灭火有关。
