Collaborative Research: Pleistocene-Holocene Climate Variability of the Southern Appalachian Region, Southeastern U.S.

最近，全新世中期暖期（MHWP）作为全球变暖预期的近未来气候条件的模拟物受到越来越多的关注。由于缺乏美国东南部内陆地区的高分辨率古气候代理记录，气候建模者不得不基于北美更知名的地区进行区域解释。然而，墨西哥湾的早期和快速变暖可能强烈影响了美国东南部的气候，导致显著的区域气候差异。本研究旨在提高对该地区更新世-全新世古水文和古气候变率的认识，特别关注MHWP的发生时间、持续时间、幅度和季节性特征以及其他气候事件的陆地足迹。本研究的目的是利用多个高质量的陆地气候代用物来提取半定量到定量的、高分辨率的、全季节的古气候历史，这些代用物保存了不同时间分辨率的记录和它们特别敏感的年季节记录。研究人员将分析来自7个地点的3个陆地档案，每个档案都保存了气候记录，具有不同但互补的时间分辨率：洞穴主题；湖泊沉积物;以及湖泊和洪泛区沉积物。已经确定了每一类记录的地点，初步研究表明这种办法的可行性。该研究结果将约束东南美国内陆气候系统的区域特征，特别是水文敏感的、人口稠密的田纳西河谷。这项研究将深入了解气候变化对水文的影响，包括融水脉冲对洪泛区发展和演变的影响。美国东南部也是研究长时间尺度人类与气候相互作用的关键地区。东南部的考古遗址揭示了多个文化转型和创新时期，包括MHWP时期早期栽培植物的证据。研究结果将提供背景和过去的环境条件与美洲原住民的占领和文化转型之间的联系。研究者实验室的古气候/环境研究项目通过课堂活动和独立研究项目与K-12学生和教师分享，通过几个扩展项目，包括NSF资助的改善田纳西州农村中学地球科学教育的K-12项目。研究人员将让学校教师参与这项研究的实地和实验室工作，并将根据本文提出的研究的各个方面继续开发实践项目。

The mid-Holocene warm period (MHWP) has recently received increased attention as an analog for near-future climate conditions expected in response to global warming. The lack of high-resolution paleoclimate proxy records for the interior southeastern US region has forced climate modelers to make regional interpretations based on better-known areas of North America. However, early and rapid warming of the Gulf of Mexico may have strongly influenced climate in the Southeastern US, resulting in significant regional climate differences. The present study seeks improved understanding of the Pleistocene-Holocene paleohydrological and paleoclimatic variability of the region, with special focus on the onset time, duration, amplitude, and seasonality characteristics of the MHWP and the terrestrial footprints of other climate events. The objective of this research is to extract a semi-quantitative to quantitative, high resolution, full-season paleoclimate history using multiple, high-quality terrestrial climate proxies that preserve records differing in temporal resolution and in the annual seasons to which they are particularly sensitive. The researchers will analyze three terrestrial archives from seven locations, each preserving a record of climate with different, but complementary, temporal resolution: speleothems; lake sediments; and lacustrine and floodplain deposits. Localities for each type of record have been identified and preliminary studies demonstrate the feasibility of this approach.The results of this study will constrain regional characteristics of the climate system in the interior SE US, especially the hydrologically-sensitive, populated Tennessee River Valley. The research will yield insights into the hydrological impact of climate changes, including meltwater pulses on floodplain development and evolution. The Southeastern US is also a critical area for investigating human-climate interaction over long time scales. Archaeological sites in the Southeast reveal multiple periods of cultural transition and innovation, including evidence for early cultivated plants during the MHWP. Research results will provide an essential linkage between context and association of past environmental conditions with Native American occupation and cultural transformation. Paleo-climate/-environmental research projects in the investigators' laboratories have been shared, through class activities and independent research projects, with K-12 students and teachers through several outreach programs, including an NSF GK-12 grant to improve Earth science education in rural middle schools in Tennessee. The investigators will involve school teachers in field and lab work for this research, and will continue to develop hands-on projects based on various aspects of the research proposed here.