We used a combination of accelerator mass spectrometry (AMS) radiocarbon dating, optically stimulated luminescence (OSL) age estimates, and stratigraphic data from cores collected along the southern margin of the Green Bay Lobe (GBL) of the Laurentide Ice Sheet to provide new information on the timing and dynamics of the end of advance of the GBL and the dynamics of the ice sheet while very near its maximum position. Coring at multiple sites along the margin of the GBL indicate that ice had reached a stable position near its maximum extent by 24.7 ka; that ice advanced several kilometers to the Marine Isotope Stage 2 maximum position sometime shortly after 21.2 ka; and that ice remained at or beyond that position through the time interval represented by an OSL age estimate of 19.2 ± 3.2 ka. The timeline developed from these chronological data is internally consistent with, and further refines, AMS radiocarbon ages and OSL age estimates previously published for the southern margin of the GBL. It also provides new chronological control on the expansion of the GBL from its late Marine Isotope Stage (MIS) 3 extent to its MIS 2 maximum.

中文翻译：

---

美国威斯康星州中南部劳伦泰德冰盖南部绿湾叶的进退动态年表

我们结合了加速器质谱 (AMS) 放射性碳测年、光激发发光 (OSL) 年龄估计以及从劳伦泰德冰盖绿湾叶 (GBL) 南缘收集的岩心的地层数据来提供新信息关于GBL前进结束的时间和动力学以及冰盖在非常接近其最大位置时的动力学。沿GBL边缘的多个地点取芯表明，冰在其最大范围附近达到了24.7 ka的稳定位置；在 21.2 ka 后不久的某个时间，冰层向海洋同位素 2 级最高位置推进了几公里；并且在 OSL 年龄估计值 19.2 ± 3.2 ka 所代表的时间间隔内，冰一直保持在该位置或超出该位置。从这些年代数据发展而来的时间线与先前为 GBL 南缘发布的 AMS 放射性碳年龄和 OSL 年龄估计值在内部是一致的，并进一步完善了这些估计值。它还为 GBL 从其晚期海洋同位素阶段 (MIS) 3 扩展到其 MIS 2 最大值提供了新的时间顺序控制。