We analyzed the δ2H composition of n-alkanes isolated from Laguna Zoncho, a small lake in southern Pacific Costa Rica, to reconstruct paleohydrology. Using a core that spans the past 3600 years, we found evidence of dry periods, most notably during the Terminal Classic Drought (TCD; ~1200 cal yr BP) and the Little Ice Age (~400 cal yr BP). Previous work at Laguna Zoncho, using bulk sedimentary δ13C and geochemical analysis, found that agriculture began to decline during the TCD. Our δ2H records confirm the occurrence of arid conditions coincident with the TCD at Laguna Zoncho and show that, despite receiving more than 3000 mm of precipitation per year, this region is susceptible to multidecadal droughts.

中文翻译：

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南太平洋哥斯达黎加创下 3600 年的干旱记录

我们分析了 δ2H组成n-从哥斯达黎加太平洋南部的一个小湖 Laguna Zoncho 中分离出的烷烃，用于重建古水文。使用跨越过去 3600 年的岩心，我们发现了干旱时期的证据，最显着的是在终极经典干旱（TCD；~1200 cal yr BP）和小冰河时代（~400 cal yr BP）期间。Laguna Zoncho 以前的工作，使用大块沉积 δ13C和地球化学分析，发现TCD期间农业开始衰退。我们的 δ2H 记录证实在 Laguna Zoncho 发生了与 TCD 相一致的干旱条件，并表明尽管每年降水量超过 3000 毫米，但该地区易受多年代干旱的影响。