Abstract We report the sedimentology, palynology, geochemistry, and diatom assemblages of a well-dated succession at Laguna Las Vueltas (LV) on the Atlantic coast of the Fuegian steppe in southern Argentina. The multiproxy analysis offers a unique opportunity to study the evolution of this coastal landscape in relation to past sea level and climate changes in the southern high latitudes. After ca. 19,000 cal yr BP, the sediments were subjected to subaerial exposure and oxidation linked to a low sea level. The Sr/Ba ratio (a paleosalinity geochemical parameter) indicates variations in the water body level, and diatoms imply the existence of an ephemeral and brackish-freshwater body subject to desiccation under arid conditions. Between ca. 11,600 and 8500 cal yr BP, a shrubby steppe vegetation, mainly composed of Asteraceae subf. Asteroideae, spread over the coastal area associated with a shallow freshwater body and the deposition of fine-grained sediments in low-energy environments, all indicative of low effective moisture and warm climate conditions. Between ca. 8500 and 8100 cal yr BP, salt carpet vegetation, dominated by Chenopodiaceae, developed around a coastal lagoon in response to the Holocene marine transgression. The record of dinocysts and geochemical data indicate marine influence at this time. Between ca. 8100 and 7000 cal yr BP, salt marshes colonized the coastal area. A coastal lagoon with a more restricted connection to the sea and minor freshwater input are inferred, linked to the beginning of a regressive phase. After ca. 7000 cal yr BP, grassland vegetation and an open shrub stratum developed along with a shallow lake (pan) that was disconnected from the sea, following a fall in the sea level and regression. Fluctuations in the water level of the pan and changes in the physical-chemical conditions, as indicated by fluctuations in Mn/Fe, Ti/Ca, Rb/Sr, Ca, TIC and TOC, suggest abrupt events of desiccation and flooding. Between ca. 4500 and 2000 cal yr BP a drier phase is indicated by changes in vegetation, algal content and geochemistry of the pan. A grassland vegetation and a shallow lake with seasonal water level variations characterized the last 2000 years. Our results from LLV area match well with Andean forest fluctuations and regional climatic conditions recorded from Tierra del Fuego and Chilean southwest.

中文翻译：

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Fuegian 草原（阿根廷火地岛北部）晚冰期-全新世沉积剖面的多重代理分析：气候变化和海平面波动对沿海景观演变的影响

摘要 我们报告了阿根廷南部 Fuegian 草原大西洋沿岸 Laguna Las Vueltas (LV) 一个年代较久的系列的沉积学、孢粉学、地球化学和硅藻组合。多代理分析提供了一个独特的机会，可以研究与南部高纬度地区过去的海平面和气候变化相关的沿海景观的演变。在大约之后。在 19,000 cal yr BP，沉积物受到与低海平面有关的地下暴露和氧化。Sr/Ba 比（一种古盐度地球化学参数）表明水体水平的变化，而硅藻则意味着存在一个在干旱条件下易干燥的短暂和微咸淡水体。之间约。11,600 和 8500 cal yr BP，灌木状草原植被，主要由菊科亚种组成。小行星科，分布在与浅淡水体和细粒沉积物在低能量环境中沉积相关的沿海地区，所有这些都表明有效湿度低和气候条​​件温暖。之间约。8500 和 8100 cal yr BP，以藜科为主的盐毯植被在沿海泻湖周围发育，以响应全新世的海侵。dinocysts 和地球化学数据的记录表明此时的海洋影响。之间约。8100 和 7000 cal yr BP，盐沼在沿海地区殖民。推断出一个与海洋连接更受限且淡水输入较少的沿海泻湖，这与回归阶段的开始有关。在大约之后。7000 cal yr BP，草原植被和开阔的灌木地层与一个与大海断开的浅湖（盘）一起发育，在海平面下降和回归之后。锅中水位的波动和物理化学条件的变化，如 Mn/Fe、Ti/Ca、Rb/Sr、Ca、TIC 和 TOC 的波动所示，表明干燥和淹没的突然事件。之间约。4500 和 2000 cal yr BP 干旱阶段由植被、藻类含量和盘的地球化学变化指示。过去 2000 年具有季节性水位变化的草原植被和浅湖。我们从 LLV 地区获得的结果与从火地岛和智利西南部记录的安第斯森林波动和区域气候条件非常吻合。TIC 和 TOC 表示干燥和洪水的突然事件。之间约。4500 和 2000 cal yr BP 干旱阶段由植被、藻类含量和盘的地球化学变化指示。过去 2000 年的特征是草地植被和具有季节性水位变化的浅湖。我们从 LLV 地区获得的结果与从火地岛和智利西南部记录的安第斯森林波动和区域气候条件非常吻合。TIC 和 TOC 表示干燥和洪水的突然事件。之间约。4500 和 2000 cal yr BP 干旱阶段由植被、藻类含量和盘的地球化学变化指示。过去 2000 年的特征是草地植被和具有季节性水位变化的浅湖。我们从 LLV 地区获得的结果与从火地岛和智利西南部记录的安第斯森林波动和区域气候条件非常吻合。