Enhanced Radiocarbon Chronology from Ohio: A Northern Hemisphere Glacial Geologic Test of Alternate Glacial Climate Hypothesis

这项拟议研究的目标是恢复上一个冰期循环期间俄亥俄州南部劳伦泰德冰盖波动的详细记录，以测试气候变化假设。与迈阿密和西奥托亚裂片冰川沉积物相关的有机物质的多重（~150）放射性碳年龄将描绘出一个高分辨率的年代学（例如，在30014C年范围内的冰期）和这些冰边缘变化的结构，直到最后一次极大期。这一记录本身将澄清巨大的劳伦泰德冰盖（冰期气候系统的关键组成部分）南部的行为。它也可能是气候变化的重要储存库。如果是这样的话，这个基本的地层记录将成为检验至少两种目前关于冰河时代气候的假设的基础。第一种观点认为，轨道变化驱动冰盖，冰盖反过来又驱动气候，从而预测冰盖生长和气候变化之间的具体领先和滞后。第二种观点认为，冰河时期的气候变化是由海洋-大气突变重组引起的，因此可以预测全球冰冻圈-大气-水圈系统的广泛、同步变化。例如，第二个假设要求北半球不同地区的冰川波动将是阶段性的，而这些波动反过来又将与南半球的冰川波动同时发生。目前对俄亥俄州南劳伦泰德波动的地层学解释不足以描述冰盖动力学或测试任何气候理论，因为它们没有充分考虑冰川沉积物的成因，而且只有微弱的（+ 2000 - 14c年）年代学控制。

The goal of the proposed research is to recover a detailed record of Laurentide Ice Sheet fluctuations in southern Ohio during the last glacial cycle to test climate-change hypotheses. Multiple (~150) radiocarbon ages from organic materials associated with glacial deposits of the Miami and Scioto sublobes will delineate a high-resolution chronology (e.g. glacial phases dated to within 30014C years) and architecture of these ice marginal changes through the last glacial maximum. This record by itself will clarify the behavior of southern sector of the huge Laurentide Ice Sheet (a key component of the ice-age climate system). It may also be an important repository of climatic change. If so, this basic stratigraphic record will be the basis for tests between at least two current hypotheses of ice-age climate. The first suggest that orbital changes drive ice sheets which in turn drive climate, thus predicting specific leads and lags between ice sheet growth and climate change. The second view suggests that ice-age climate changes result from abrupt ocean-atmospheric reorganizations, thus predicting widespread, synchronous changes across the global cryosphere-atmosphere-hydrosphere system. For example, the second hypothesis requires that glacial fluctuations in various parts of the Northern Hemisphere will be in phase and that these in turn, will be concurrent with glacial fluctuations in the Southern Hemisphere. Present stratigraphic interpretations of southern Laurentide fluctuations in Ohio are inadequate to delineate ice- sheet dynamics or test any climate theories because they have not fully considered the genesis of glacial deposits and have only weak (+2,00014C years) chronologic control.