Several decades of ice-penetrating radar surveys of the Greenland and Antarctic ice sheets have observed numerous widespread internal reflections. Analysis of this radiostratigraphy has produced valuable insights into ice sheet dynamics and motivates additional mapping of these reflections. Here we present a comprehensive deep radiostratigraphy of the Greenland Ice Sheet from airborne deep ice-penetrating radar data collected over Greenland by The University of Kansas between 1993 and 2013. To map this radiostratigraphy efficiently, we developed new techniques for predicting reflection slope from the phase recorded by coherent radars. When integrated along track, these slope fields predict the radiostratigraphy and simplify semiautomatic reflection tracing. Core-intersecting reflections were dated using synchronized depth-age relationships for six deep ice cores. Additional reflections were dated by matching reflections between transects and by extending reflection-inferred depth-age relationships using the local effective vertical strain rate. The oldest reflections, dating to the Eemian period, are found mostly in the northern part of the ice sheet. Within the onset regions of several fast-flowing outlet glaciers and ice streams, reflections typically do not conform to the bed topography. Disrupted radiostratigraphy is also observed in a region north of the Northeast Greenland Ice Stream that is not presently flowing rapidly. Dated reflections are used to generate a gridded age volume for most of the ice sheet and also to determine the depths of key climate transitions that were not observed directly. This radiostratigraphy provides a new constraint on the dynamics and history of the Greenland Ice Sheet. KEY POINTS Phase information predicts reflection slope and simplifies reflection tracingReflections can be dated away from ice cores using a simple ice flow modelRadiostratigraphy is often disrupted near the onset of fast ice flow.

中文翻译：

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格陵兰冰原的放射地层学和年龄结构。

几十年来，格陵兰和南极冰原的穿透冰的雷达调查已经观察到许多广泛的内部反射。对该射电地层学的分析已对冰盖动力学产生了宝贵的见解，并激发了对这些反射的更多测绘。在这里，我们根据堪萨斯大学在1993年至2013年间在格陵兰岛上收集的机载穿透冰层的深层雷达数据，提供了格陵兰冰原的全面深层放射地层学。为了有效地绘制该放射地层学图，我们开发了新的技术来预测相反射斜率由相干雷达记录。当沿轨道整合时，这些斜率场可预测射电地层并简化半自动反射描迹。使用六个深冰芯的同步深度-年龄关系确定了相交反射的日期。通过匹配样条线之间的反射以及通过使用局部有效垂直应变率扩展反射推断的深度-年龄关系来确定其他反射的年代。最古老的反射，可追溯到Eemian时期，主要发现在冰盖的北部。在几个快速流动的出口冰川和冰流的爆发区域内，反射通常不符合床的地形。在东北格陵兰冰河以北目前尚未迅速流动的地区，也观察到射电地层破裂。日期反射可用于为大多数冰盖生成网格化的年龄量，并用于确定未直接观测到的关键气候转变的深度。该放射地层学对格陵兰冰原的动力学和历史提供了新的约束。要点相位信息可预测反射斜率并简化反射描记使用简单的冰流模型可以将反射定为离冰芯较远的位置。射影地层学经常在快速冰流开始时被破坏。