Collaborative Research: Paleoenvironmental Changes in the Bolivian Altiplano: A High-Resolution Pollen Record from the Sajama Ice Cap

该项目旨在制作玻利维亚高原萨哈马冰盖过去25,000年来气候和植被变化的高分辨率花粉记录。保存在萨哈马冰盖冰芯中的花粉将以每年到十年的采样分辨率进行分析，以检测热带安第斯植被对全新世晚期发生的世纪尺度气候波动的反应，例如小冰期、中世纪暖期，以及在过去3500年间周期性降低喀喀湖水位的区域性干旱事件。花粉数据还将补充其他古气候指标，以揭示在末次冰盛期和去冰期发生的突然气候变化的植被响应，包括大约14,000到11,500年前与北大西洋年轻仙女座相关的一次去冰川气候逆转。这项研究将是第一次对热带冰芯进行系统的花粉研究。这将推动冰芯孢粉学领域的发展，并将加强花粉在冰芯研究中作为古气候和古生态替代品的利用。来自萨哈马冰盖的25000年的花粉记录将只是赤道以南整个热带安第斯山脉和西亚马逊地区的另一份连续的花粉记录，其中包含与最后一次冰盛期的植被和气候条件有关的信息。这将为研究热带安第斯植被对过去和未来气候变化的敏感性提供一个独特的机会。

This project seeks to produce a high-resolution pollen record of climatic and vegetational changes during the last 25,000 years from the Sajama ice cap in the Altiplano of Bolivia. Pollen preserved in ice cores retrieved from the Sajama ice cap will be analyzed at annual to decadal sampling resolutions to detect the response of the tropical Andean vegetation to century-scale climatic fluctuations occurring during the late-Holocene, such as the Little Ice Age, the Medieval Warm Period, and the regional drought events that episodically lowered the water levels in Lake Titicaca during the last 3500 years. The pollen data will also complement other paleoclimatic proxies to shed light on the vegetational response to abrupt climatic changes occurring during the Last Glacial Maximum and deglacial times, including a deglaciation climatic reversal about 14,000 to 11,500 years ago that is correlative with the North Atlantic Younger Dryas stadial.This research will be the first systematic pollen study of a tropical ice core. It will advance the field of ice-core palynology and will enhance the use of pollen as a paleoclimatic and paleoecological proxy in ice-core research. The 25,000-year pollen record from the Sajama ice cap will add to only one other continuous pollen record from the entire tropical Andes and western Amazonia south of the equator that contains information pertaining to the vegetation and climatic conditions of the Last Glacial Maximum. It will offer a unique opportunity to study the sensitivity of the tropical Andean vegetation to past and future climatic changes.