ESH - Climate Variability and Ecologic Change in Mesoamerica During the Late Holocene: Implications for Maya Cultural Evolution

小行星9709314 位于危地马拉北方的佩腾省，代表着3000多年前古玛雅文明兴起的中心地区，在所谓的古典时期繁荣，在公元800 - 900年左右神秘地崩溃。 大崩溃的原因已经被考古学家争论了世纪。 气候变化被认为是一个促成因素，但这一假设尚未得到严格的检验。 我们以前的工作，由NOAA古气候学资助，试图了解气候变化可能在玛雅文明崩溃中发挥的作用。 我们从尤卡坦半岛中部和北方的两个湖泊中发现了令人信服的古气候证据，证明公元800年至1000年之间的长期干旱与经典玛雅崩溃相吻合（Hodell等人，1995; Curtis等人，1996年）。 尤卡坦半岛湖泊和秘鲁奎尔卡亚冰芯之间的古气候记录的干旱事件的相关性表明，干旱是广泛的中美洲和南美洲在过去的1500年，并可能与大规模的大气和海洋领域的偏离。 在这里，我们打算测试尤卡坦半岛记录的干旱是否影响了危地马拉佩滕的玛雅南部低地，那里的玛雅人口密度最高，崩溃最严重。 我们建议收集地球化学，孢粉学和沉积物的数据，从沉积岩芯采取在北湖地区重建气候和生态变化的足够详细，以揭示几十年到百年的波动在过去的5,000年。 具体来说，我们将测量的氧同位素比值的微体化石壳（介形虫和腹足类）从核心采取在封闭的盆地湖泊和重建的蒸发量与降水量（E/P）的比值在集水区的变化。 我们还将记录来自相同岩心的花粉光谱的地层变化，以重建可能受到气候因素和/或人类影响的区域植被变化。 拟议的研究将阐明在晚全新世在玛雅低地的E/P和植被的变化的空间和时间模式。 北碇的古环境记录将有助于我们了解：1。新热带低地全新世自然水文气象变化的全方位; 2.）与其他地区气候记录（海洋、湖泊和冰芯记录）的遥相关联系; 3.）古典玛雅社会和经济系统对气候和生态变化的反应。

9709314 Hodell The Department of Peten in northern Guatemala represents the central area where ancient Maya civilization arose more than 3000 years ago, flourished during the so-called Classic Period, and mysteriously collapsed around 800 - 900 AD. The cause of the Collapse has been debated by archaeologists for over a century. Climate change has been suggested as a contributing factor, but this hypothesis has not been tested rigorously. Our previous work, funded by NOAA-Paleoclimatology, sought to understand the role that climate change may have played in the collapse of Maya civilization. We discovered compelling paleoclimatic evidence from two lakes in central and northern Yucatan for a protracted drought between ~800 and 1000 AD that coincided with the Classic Maya Collapse (Hodell et al., 1995; Curtis et al., 1996). Correlation of arid events in paleoclimate records between Yucatan lakes and the Peruvian Quelccaya ice core suggests that aridity was widespread in Central and South America over the last 1500 years, and may have been related to large-scale departures in atmospheric and oceanic fields. Here we propose to test if the droughts documented in Yucatan affected the southern Maya lowlands of Peten, Guatemala, where Maya population densities were highest and the Collapse was most profound. We propose to collect geochemical, palynological, and sedimentologic data from sediment cores taken in the Peten Lake District to reconstruct climatic and ecologic changes in sufficient detail to reveal decadal to centennial fluctuations over the past 5,000 years. Specifically, we will measure oxygen isotopic ratios in microfossil shells (ostracods and gastropods) from cores taken in close-basin lakes and reconstruct changes in the ratio of evaporation to precipitation (E/P) over the catchment. We will also document stratigraphic changes in pollen spectra from the same cores to reconstruct regional vegetation changes that may have been influenced by climatic factors and/or human impact. The proposed study will elucidate the spatial and temporal pattern of changes in E/P and vegetation in the Maya lowlands during the late Holocene. Paleoenvironmental records from Peten will contribute to our understanding of: 1.) the full range of natural hydrometeorologic variability during the Holocene in the lowland Neotropics; 2.) teleconnective linkages with climatic records (marine, lacustrine, and ice core records) from other regions; and 3.) the response of Classic Maya social and economic systems to climate and ecologic change.