Abstract Laguna Mar Chiquita (LMC, 30°54′S – 62°51′W) is a highly variable and shallow saline lake, located in the Pampean Plains of Argentina. The paleolimnological record of LMC contains information on the environmental variability that occurred in a large area of Southern South America since the Last Glacial Maximum (LGM) until the present. As inferred from the diatom assemblages, sedimentary features and geochemical proxies, prolonged intervals of high and lowstands have caused variations in water salinity, trophic state and sedimentary processes. This is the first paleolimnological reconstruction covering the hydroclimatic variability that occurred over the last 25,000 cal yr BP in the Argentinean Pampean region. Results are in accordance with well-known global climatic phases. The Late Pleistocene record is characterized by a scenario dominated by lowstands, hypersaline, and oligotrophic lake conditions. Radiocarbon ages (25,000–19,000 cal yr BP) indicate that the onset of the record is coeval with the LGM. Later, a progressive lake water level increase was registered at ⁓17,000 cal yr BP, which can be assigned to the Heinrich Stadial 1. A shift toward comparatively drier conditions identified in the record between ⁓14,700 and 13,000 cal yr BP can be chronologically related to the Antarctic Cold Reversal. The transition from the Late Pleistocene to the Holocene (13,500–10,500 cal yr BP) is recorded by highstand phases while the Early Holocene record is characterized by high to intermediate water levels. The hydrological reconstruction corresponding to the Mid-Holocene is characterized by alternating phases of high/lowstands. The onset of the Late Holocene record is marked by the development of dry conditions and thus lowstand phases, while around 1300 cal yr BP a distinct water lake level increase is recognized. This humid phase, ascribed to the Medieval Climatic Anomaly, is followed by the record of lowstands between 500 and 1000 cal yr BP, being coeval with the Little Ice Age. The uppermost part of the record of LMC encompasses the Current Warm Period, showing a marked shift towards high lake water level conditions. The hydrological variability registered in the paleolimnological record, highlights the importance of Laguna Mar Chiquita as an outstanding paleoclimate sensor of hydroclimatic variations for a large area of South Eastern South America.

中文翻译：

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Pampean 平原（阿根廷）的古湖水学记录是自 LGM 到当前暖期以来南美水文气候变化的自然档案

摘要 Laguna Mar Chiquita (LMC, 30°54'S – 62°51'W) 是一个高度可变的浅盐湖，位于阿根廷的潘潘平原。LMC 的古湖泊记录包含自末次盛冰期 (LGM) 以来南美洲南部大片地区发生的环境变化的信息。从硅藻组合、沉积特征和地球化学指标推断，高低位间隔的延长导致了水盐度、营养状态和沉积过程的变化。这是第一次古湖泊学重建，涵盖了过去 25,000 cal 年 BP 在阿根廷潘潘地区发生的水文气候变化。结果与众所周知的全球气候阶段一致。晚更新世记录的特点是低水位、高盐度和贫营养湖泊条件占主导地位。放射性碳年龄（25,000–19,000 cal yr BP）表明记录的开始与LGM同时期。后来，湖水位逐渐升高，记录为 ⁓ 17,000 cal yr BP，这可以归为 Heinrich Stadial 1。在⁓14,700 和 13,000 cal yr BP 之间的记录中确定的向相对干燥条件的转变可以按时间顺序与南极冷逆转。从晚更新世到全新世（13,500-10,500 cal yr BP）的转变是由高位相记录的，而早期全新世记录的特征是高到中等水位。对应于中全新世的水文重建以高低位交替相为特征。晚全新世记录的开始以干燥条件的发展和低水位阶段为标志，而在 1300 cal yr BP 左右，水湖水位明显增加。这一潮湿阶段归因于中世纪气候异常，随后是 500 至 1000 cal BP 之间的低位记录，与小冰河时代同时期。LMC 记录的最上部包括当前暖期，显示出向高湖水位条件的显着转变。古湖泊记录中记录的水文变异性，