Abstract. The 4.2 kyr event is regarded as one of the largest and best documented abrupt climate disturbances of the Holocene. Drying across the Mediterranean and Middle East is well established and is linked to societal transitions in the Akkadian, Egyptian and Harappan civilizations. Yet the impacts of this regional drought are often extended to other regions and sometimes globally. In particular, the nature and spatial extent of the 4.2 kyr event in the tropics have not been established. Here, we present a new stalagmite stable isotope record from Anjohikely, northwest Madagascar. Growing between 5 and 2 kyr BP, stalagmite AK1 shows a hiatus between 4.32 and 3.83 kyr BP, replicating a hiatus in another stalagmite from nearby Anjohibe, and therefore indicating a significant drought around the time of the 4.2 kyr event. This result is the opposite to wet conditions at 8.2 kyr BP, suggesting fundamentally different forcing mechanisms. Elsewhere in the south-east African monsoon domain dry conditions are also recorded in sediment cores in Lake Malawi and Lake Masoko and the Taros Basin on Mauritius. However, at the peripheries of the monsoon domain, drying is not observed. At the northern (equatorial East Africa) and eastern (Rodrigues) peripheries, no notable event is record. At the southern periphery a wet event is recorded in stalagmites at Cold Air Cave and sediment cores at Lake Muzi and Mkhuze Delta. The spatial pattern is largely consistent with the modern rainfall anomaly pattern associated with weak Mozambique Channel Trough and a northerly austral summer Inter Tropical Convergence Zone position. Within age error, the observed peak climate anomalies are consistent with the 4.2 kyr event. However, outside Madagascar, regional hydrological change is consistently earlier than a 4.26 kyr BP event onset. Gradual hydrological change frequently begins at 4.6 kyr BP, raising doubt as to whether any coherent regional hydrological change is merely coincident with the 4.2 kyr event rather than part of a global climatic anomaly.

中文翻译：

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4.2喀尔事件在马达加斯加和东南非洲季风中的可能表达

摘要。4.2 kyr事件被认为是全新世最大，记录最充分的气候突变之一。地中海和中东地区的干旱已经很成熟，并且与阿卡德，埃及和哈拉潘文明的社会转型有关。然而，这种地区性干旱的影响通常扩展到其他地区，有时甚至扩展到全球。特别是，尚未确定热带地区4.2 kyr事件的性质和空间范围。在这里，我们提出了来自马达加斯加西北部安乔希克利的新的石笋稳定同位素记录。石笋AK1生长在5至2年BP之间，其裂隙介于4.32至3.83年BP之间，复制了附近安乔希贝岛另一石笋中的裂隙，因此表明在4.2年事件发生时出现了严重的干旱。该结果与8.2 kry BP的湿润条件相反，表明根本不同的强迫机制。在东南非洲季风区的其他地方，马拉维湖，马索科湖和毛里求斯的塔罗斯盆地的沉积物芯中也记录了干旱情况。然而，在季风域的外围，没有观察到干燥。在北部（赤道东非）和东部（罗德里格斯）外围，没有记录到明显的事件。在南部外围，冷空气洞穴的石笋和木子湖和姆库兹河三角洲的沉积物核心都记录到了湿事件。空间格局在很大程度上与现代的莫桑比克海槽低谷和北半球夏季夏季热带辐合带位置相关的降雨异常模式一致。在年龄误差内，观测到的高峰气候异常与4.2 kyr事件一致。但是，在马达加斯加以外，区域水文变化始终早于BP事件4.26年爆发。逐渐的水文变化通常始于4.6 kyr BP，这使人们怀疑是否任何连贯的区域水文变化仅与4.2 kyr事件一致，而不是全球气候异常的一部分。