Holocene Climate Change and its Effect on the Mayan Aquifer of the Yucatan Peninsula, Mexico

每年，成千上万的加拿大人在尤卡坦半岛玛雅里维埃拉的大型度假胜地度假；逗留期间经常在附近的天然井游泳。大多数人都没有意识到这些天然井是一个巨大的地下洞穴系统的入口，这个洞穴系统延伸到度假村下面，对当地居民来说是一个重要的含水层。由于地下水开采和废物污染，这一含水层受到人类发展日益严重的威胁。含水层对更大尺度的因素也非常敏感，如全球海平面上升（预计到21世纪末海平面将上升1米），以及气候变化的其他影响（如降水、飓风频率）。我的研究计划的长期目标是研究喀斯特含水层的水文演变及其与全新世气候和海平面变化的关系，重点是尤卡坦半岛。喀斯特含水层在世界各地的沿海地区占主导地位，但在热带和亚热带地区尤其如此，在那里，数千年的珊瑚礁生长加上海洋和陆地的变化导致了大片多孔石灰岩。这些喀斯特含水层是一种大气水团，位于从海岸侵入多孔石灰岩的海洋水团之上。由于尤卡坦半岛新近纪/第四纪石灰岩具有多孔性，雨水渗透到地下水位并流向海岸，大气水团的盐度受盐斜的流动模式控制，但两者之间的关系尚不清楚。因此，尽管我们对水团在正常条件下如何相互作用有了一个大致的了解（仪器监测），但这种关系的复杂性还没有得到很好的理解，而且对水团如何响应全新世海平面上升和气候变化知之甚少。该研究计划将在沉积物岩心中开发一种新的古环境指标（氯），用于重建尤卡坦半岛苯胺含水层的长期演变，并研究与气候循环的关系，建立边界条件和未来对含水层的影响。这项研究的结果也将有助于解决关于大约12- 13000年前迁移到尤卡坦半岛的古美洲人的重要考古问题，以及关于古典玛雅文明衰落的争论，古典玛雅文明的衰落与公元8 - 9世纪的干旱时期有关。尤卡坦半岛玛雅社会的兴衰与气候湿润和干燥时期有关，尽管这种关系存在空间复杂性，尚未得到解释，并且在研究人员之间存在激烈争论。拟议的研究将通过重建过去4- 5000年来含水层和湖水的盐度或（可饮用性）来促进这场辩论。

Every year, thousands of Canadians vacation at large resorts on the Yucatan Peninsula's Maya Riviera; often swimming in nearby cenotes during their stay. Most are not aware that these cenotes are entry points for a vast subterranean cave system that extends beneath the resorts which is an important aquifer for the local population. This aquifer is under increased threat from human development through groundwater extraction and waste contamination. The aquifer is also very sensitive to larger scale factors such as global sea-level rise which is predicted to be 1m by the end of the 21st century, as well as other effects of climate change (e.g. precipitation, frequency of hurricanes). The long-term goal of my research program is to examine the hydrological evolution of karst aquifers and their relationship with Holocene climate and sea-level change with a focus on the Yucatan Peninsula. Karst aquifers predominate coastal areas around world, but especially in tropical and subtropical areas where millennia of reef growth coupled with sea and land-level change has resulted in large tracts of porous limestone. These karst aquifers (anchialine) are a meteoric water mass resting on top of a marine water mass that intrudes from the coast through the porous limestone. Because the Neogene/Quaternary limestone of the Yucatan peninsula is so porous, rainwater penetrates to the water table and flows to the coast with the salinity of the meteoric water mass being controlled by flow patterns at the halocline, but the relationship is poorly known. So, although we have a general understanding (instrumental monitoring) on how the water masses interact under normal conditions, the complexity of the relationship is not well understood, and there is little knowledge on how water masses responded to Holocene sea-level rise and climate change. The proposed research program will develop a new paleoenvironmental indicator (chlorine) in sediment cores for reconstructing the long-term evolution of the anchialine aquifer of the Yucatan and examine relationships with climate cycles establishing boundary conditions and future impacts on the aquifer. The outcomes from this research will also contribute to important archaeological questions regarding Paleoamericans who migrated to the Yucatan approximately 12-13,000 yrs ago, and to the debate about the decline of the Classic Maya which has been linked to a period of drought in the 8th and 9th c. AD. The rise and fall of Mayan societies in the Yucatan have been linked with climatically wet and dry periods, although there is spatial complexity in this relationship that remains unexplained and is highly debated amongst researchers. The proposed research will contribute to this debate by reconstructing the salinity or (potability) of the aquifer and lake water over the past 4-5,000 years.