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

这项拟议的研究的目标是恢复上一次冰川周期期间俄亥俄州南部劳伦蒂德冰盖波动的详细记录，以检验气候变化假说。来自与迈阿密和肖托亚球体冰川沉积有关的有机物质的多个(~150)放射性碳年龄将描绘出高分辨率的年代学(例如，30014C年内的冰期)和这些冰缘在最后一次冰盛期期间的结构变化。这一记录本身将阐明巨大的劳伦蒂德冰盖(冰期气候系统的关键组成部分)南段的行为。它也可能是气候变化的重要储存库。如果是这样的话，这一基本的地层记录将成为检验目前至少两种冰河时代气候假说的基础。第一项研究表明，轨道变化推动了冰盖，而冰盖反过来又推动了气候变化，从而预测了冰盖增长和气候变化之间的具体领先和滞后。第二种观点认为，冰河时代的气候变化是海洋-大气突然重组的结果，从而预测了全球冰冻圈-大气-水圈系统广泛、同步的变化。例如，第二个假设要求北半球不同地区的冰川波动将是同相的，而这些又将与南半球的冰川波动同时发生。目前对俄亥俄州南部Laurentide波动的地层学解释不足以描述冰盖动力学或检验任何气候理论，因为它们没有充分考虑冰川沉积的成因，只有微弱的(+2,00014 C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.