Collaborative Research: Late Pleistocene and Earliest Holocene Evolution of the Lower Mississippi Valley

合作研究：密西西比河谷下游的晚更新世和最早全新世演化

• 批准号: 0106733
• 负责人: Margaret Guccione
• 金额: $ 10.3万
• 依托单位: University of Arkansas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0106733&HistoricalAwards=false
• 关键词: Collaborative; Research; Late; Pleistocene; Earliest

GuccioneThe Lower Mississippi Valley (LMV) has the potential of understanding the linkages of upstream climate/glacial vs. downstream sea level controls of a large stream system. In addition a stratigraphic and geochronologic framework for the alluvial landforms of the valley will aid in the study of tectonic activity within the New Madrid seismic zone, within the northern valley. This proposed research seeks to develop a chronologic and genetic model for evolution of the LMV during the Late Pleistocene full glacial (late Wisconsin stage) to the earliest Holocene, a period when rapid large-scale rearrangements of the North American hydrological system occurred. These rearrangements included changes in the Laurentide ice-sheet margin, drainage of pro-glacial lakes, and se level rise. This proposal focuses on a) the role of fluctuations in discharge and sediment load from the former ice margin, b) downstream effects of sea level discharge, and c) the impact of these forcing mechanisms on landscape evolution in the LMV. We hope to address the following questions:o How do landforms and deposits of the LMV correlate to ice margin changes, floods from pro-glacial lakes, and/or specific meltwater and sediment spikes identified in the Gulf of Mexico?o How do landforms and deposits of the LMV correlate to the landforms and deposits of the upper Mississippi valley where climate/glacail impacts were fundamental, but sea level played no role?o Does the LMV respond rapidly to high-frequency changes in discharge and sediment load during deglaciation, or are there lag times? Does the signal decay downstream or is it present to the Gulf of Mexico?What is the influence of sea level and how far upstream does it extend?

下密西西比河谷（LMV）有可能了解上游气候/冰川与下游海平面控制的大型河流系统的联系。 此外，河谷冲积地貌的地层学和地质年代学框架将有助于研究北方河谷内新马德里地震带的构造活动。这项拟议中的研究旨在开发一个年表和遗传模型的LMV在晚更新世全冰期（晚威斯康星州阶段）最早的全新世，北美水文系统发生快速大规模重排的时期。 这些重新安排包括劳伦蒂德冰盖边缘的变化，前冰川湖泊的排水和硒水平上升。 该建议的重点是a）流量和泥沙负荷的波动的作用，从以前的冰缘，B）海平面流量的下游效应，和c）在LMV景观演变的影响，这些强迫机制。 我们希望解决以下问题：o LMV的地貌和沉积物如何与冰缘变化、前冰川湖泊洪水和/或墨西哥湾确定的特定融水和沉积物峰值相关？LMV的地貌和沉积物如何与密西西比河谷上游的地貌和沉积物相关联，在那里气候/冰川的影响是根本性的，但海平面没有发挥作用？在冰川消退期间，LMV是否对流量和泥沙负荷的高频变化迅速作出反应，或者是否存在滞后时间？ 信号是在下游衰减还是在墨西哥湾出现？海平面的影响是什么？它向上游延伸了多远？