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

每年，数以千计的加拿大人在尤卡坦半岛玛雅里维埃拉的大型度假村度假；在逗留期间，他们经常在附近的中心游泳。大多数人没有意识到，这些洞穴是一个巨大的地下洞穴系统的入口点，这个洞穴系统延伸到度假村下面，对当地居民来说，这是一个重要的含水层。由于地下水开采和废物污染，该含水层正受到人类发展的日益严重的威胁。含水层对更大范围的因素也非常敏感，如全球海平面上升，预计到21世纪末将达到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岩溶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。 岩溶含水层主要分布在世界各地的沿海地区，尤其是在热带和亚热带地区，那里几千年来珊瑚礁的生长加上海平面和陆地水平的变化导致了大片多孔的石灰岩。这些岩溶含水层是位于海洋水团之上的大气水团，海洋水团从海岸侵入，穿过多孔的石灰岩。由于尤卡坦半岛新近系/第四系石灰岩具有很强的渗透性，雨水渗入地下水位并流向海岸，大气水团的盐度受盐跃层流型的控制，但这种关系却鲜为人知。因此，尽管我们对水团在正常条件下如何相互作用有了大致的了解(仪器监测)，但这种关系的复杂性还没有被很好地理解，关于水团如何对全新世海平面上升和气候变化做出反应的知识也很少。拟议的研究计划将在沉积物岩心中开发一种新的古环境指标(氯)，以重建尤卡坦地区Anchialine含水层的长期演变，并审查与气候周期的关系，确定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提出关于大约12-13,000年前迁徙到尤卡坦半岛的古美洲人的重要考古学问题，以及关于经典玛雅人衰落的辩论，这与公元8-9年的一段干旱时期有关。玛雅社会在尤卡坦半岛的兴衰与气候的湿润和干旱有关，尽管这种关系存在着空间上的复杂性，至今仍未得到解释，研究人员对此进行了激烈的辩论。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(潜势)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.