Isotope and Pollen Stratigraphy of Abrupt Late Glacial Climate Events in the Upper Midwest

自然气候和生态系统都可能对渐进的压力做出突然反应。在距今14,000年到10,000年的冰川晚期，几十年内发生了巨大的变化。该项目将审查五大湖以南气候敏感的中西部地区两个具有不同响应率的气候指标的综合近距离样本的记录。我们将使用湖泊沉积物碳酸盐中存在的稳定同位素作为对区域降水模式变化的几乎瞬时响应的替代测量。我们将用花粉沉积作为区域植被(以及间接气候)的替代指标，给出一个具有时间滞后的记录。包括俄亥俄州、印第安纳州、密歇根州和伊利诺伊州在内的地区将接受检查。这些地点将允许直接比较不同系统在约13,000 BP的晚期冰川和约10,200 BP的年轻Dryas Chron两次变暖事件期间的响应速度。

Both natural climate and ecosystems may respond abruptly to gradual forcings. During the late glacial time window between 14,000 and 10,000 years BP, large magnitude changes occurred within decades. This project will examine the records from integrated close-interval samples of two different climate proxies with different response rates in the climatically sensitive Midwest region south of the Great Lakes. We will use stable isotopes present in lake sediment carbonates as a proxy measure of almost instantaneous response to changes in regional precipitation patterns. We will use pollen deposition as a proxy for regional vegetation (and indirectly climate), giving a record with a time lag. The area including Ohio, Indiana, Michigan, and Illinois will be examined. These sites will allow direct comparison of response rate of different systems during the two warming events in the late glacial around 13,000 BP, and in the Younger Dryas Chron around 10,200 BP.