Abstract Siliceous sinter deposits from El Tatio, Chile, preserve a wide variety of depositional environments and biosignatures, from high-temperature (~85 °C) vent-proximal facies to distal deposits dominated by silicified microbial mats. Four cores were drilled into an El Tatio sinter mound and associated distal apron to investigate changes in hydrothermal environments over geologic timescales. Sedimentary and geochemical analysis of multiple sinter cores records the initiation and accretion of diverse depositional features still observed today in El Tatio. Facies adjacent to hydrothermal vents are dominated by laminated sinter crusts on the steep margins of a high-temperature pool, with sparse microbial preservation. Outer margins of the same pool contain extensive sinter columns up to ten centimeters in length, precipitated during repeated cycles of pool overflow and subsequent evaporation. Low-relief hydrothermal pools also form minor deposits within distal debris aprons, and analogous pools are still active close to sampling locations. Debris aprons are dominated by palisade, tufted, and arborescent microbial fabrics, with distinct mat textures revealing well preserved microfossils. Surficial deposits in all cores feature detrital-rich and microbially-influenced sinters overlying higher-temperature facies, indicating a relative decrease in hydrothermal activity over time. Geochemical proxies for hydrothermal fluids and detrital input match depositional interpretations based on sedimentary structures. 14C ages from core deposits extend the mound's history by 11,000 years, recording at least three thousand years of sinter deposition on top of glacial sandstones (13,337–10,232 y. cal. BP). Importantly, this work provides a detailed depositional model unavailable through surficial sedimentology alone.

中文翻译：

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智利 El Tatio 一个已灭绝的烧结堆从源头到流出的沉积演化

摘要 智利 El Tatio 的硅质烧结矿床保存了各种各样的沉积环境和生物特征，从高温 (~85 °C) 近喷口相到以硅化微生物垫为主的远端沉积物。四个岩心被钻入 El Tatio 烧结土丘和相关的远端围裙，以研究地质时间尺度上热液环境的变化。多个烧结岩心的沉积和地球化学分析记录了今天仍然在 El Tatio 观察到的各种沉积特征的开始和增生。与热液喷口相邻的相以高温池陡峭边缘的层状烧结结壳为主，微生物保存稀少。同一池的外缘包含长达十厘米的大量烧结柱，在池溢流和随后的蒸发的重复循环中沉淀。低地势热液池也在远端碎屑围裙内形成少量沉积物，类似的池仍在采样位置附近活动。碎片围裙以栅栏、簇绒和树状微生物织物为主，具有独特的垫子纹理，显示出保存完好的微化石。所有岩心的地表沉积物都具有富含碎屑和微生物影响的烧结矿，覆盖在高温相上，表明热液活动随着时间的推移相对减少。热液流体和碎屑输入的地球化学代表与基于沉积结构的沉积解释相匹配。来自核心矿床的 14C 年龄将土墩的历史延长了 11,000 年，记录了冰川砂岩顶部至少三千年的烧结沉积（13,337–10,232 y. cal. BP）。重要的是，这项工作提供了仅通过地表沉积学无法获得的详细沉积模型。