Speleothem based quantification of precipitation and aridity and its role for Maya cultural development on the northern Yucatán Peninsula, Mexico

玛雅文明在中美洲的不同文化演变和最终崩溃是激烈争论的问题，讨论包括自然灾害（如干旱，飓风，火山爆发）和社会灾害（如战争和不可持续的经济）的影响。越来越多的记录报告了不寻常的干旱状况，与建筑业的中断、城市暂时废弃和人口崩溃的阶段相吻合。以前的重建表明，尤卡坦半岛的环境条件和降水在空间和时间上分布非常不均匀。此外，事件的持续时间和先后顺序仍然不确定。因此，在本项目中，我们建议通过研究Estrella洞穴洞穴中的高分辨率地球化学示踪剂来改善降雨模式（即干旱和极端降水）的时间和年代。因此，这将有助于提高北方尤卡坦半岛古气候变化和玛雅文化演变的一致性。作为DFG资助的试点项目的一部分，我们发现巴利亚多利德附近的Estrella洞穴不仅拥有重要的玛雅考古遗迹，建筑和墓地，可能可以追溯到早期的古典玛雅时期，而且还有许多洞穴，具有跨越整个玛雅时代的潜在独特气候信息。初步的高精度230 Th/U年龄显示石笋的持续生长超过3000年，包括玛雅人的进化，甚至达到历史时期。此外，初步分析表明，这些石笋中的某些微量元素的掺入与洞穴上方补给的变化密切相关。在这里，我们将产生一个新的，复制的，独特的解决和准确的年代记录过去的降水在该地区的基础上，在这些洞穴中的微量元素和稳定的C和O同位素的代理分析。通过这些记录，沿着气候和文化信息的综合汇编，我们将评估灾难性自然事件的影响，如干旱，火山爆发，飓风，以及它们对玛雅文化历史的复合具体影响。这个项目和一个地球化学监测项目得到了当地洞穴学家、气候科学家和考古学家的支持。

The varied cultural evolution and final collapse of Maya civilization in Mesoamerica are heavily debated issues and discussions include the impact of both natural (e.g. droughts, hurricanes, volcanic eruptions), and social disasters (e.g. warfare and unsustainable economy). An increasing number of records report unusual dry conditions coinciding with hiatuses in construction, phases of temporary urban abandonment and population collapse. Previous reconstructions indicate that environmental conditions and precipitation on the Yucatan Peninsula were distributed very heterogeneously in space and time. In addition, the duration and chronology of events remains uncertain. Hence, in this project we propose to improve the timing and chronology of rainfall patterns (i.e. droughts and extreme precipitation) through the study of geochemical tracers at high resolution in speleothems from Estrella cave. This would thus permit to improve the coherence of paleoclimate change and Maya cultural evolution in northern Yucatan. As part of a DFG funded pilot-project we have discovered that Estrella cave near Valladolid not only hosts important Maya archaeological remains, constructions, and a graveyard, likely dating to the early classical Maya period, but also numerous speleothems with potentially unique climate information spanning the entire Maya era. Preliminary high precision 230Th/U-ages demonstrate continuous growth of stalagmites over more than 3000 years including the Maya evolution and reaching to even historical times. Furthermore, first analyses show that the incorporation of certain trace elements in these stalagmites is strongly related to changes in recharge above the cave. We will here generate a novel, replicated, uniquely resolved and accurately dated record of past precipitation in the area based on proxy analysis of trace elements and stable C and O isotopes in these speleothems. Through these records, along with comprehensive compilation of climate and cultural information, we will evaluate the influence of catastrophic natural events such as droughts, volcanic eruptions, hurricanes, and their compound specific impact on the Maya cultural history. This project, and a geochemical monitoring program, is supported by local speleologists, climate scientists and archeologists.