Escanaba Trough is the southernmost segment of the Gorda Ridge and is filled by sandy turbidites locally exceeding 500 m in thickness. New results from Ocean Drilling Program (ODP) Sites 1037 and 1038 that include accelerator mass spectrometry (AMS) 14C dates and revised petrographic evaluation of the sediment provenance, combined with high‐resolution seismic‐reflection profiles, provide a lithostratigraphic framework for the turbidite deposits. Three fining‐upward units of sandy turbidites from the upper 365 m at ODP Site 1037 can be correlated with sediment recovered at ODP Site 1038 and Deep Sea Drilling Program (DSDP) Site 35. Six AMS 14C ages in the upper 317 m of the sequence at Site 1037 indicate that average deposition rates exceeded 10 m/k.yr. between 32 and 11 ka, with nearly instantaneous deposition of one ∼60‐m interval of sand. Petrography of the sand beds is consistent with a Columbia River source for the entire sedimentary sequence in Escanaba Trough. High‐resolution acoustic stratigraphy shows that the turbidites in the upper 60 m at Site 1037 provide a characteristic sequence of key reflectors that occurs across the floor of the entire Escanaba Trough. Recent mapping of turbidite systems in the northeast Pacific Ocean suggests that the turbidity currents reached the Escanaba Trough along an 1100‐km‐long pathway from the Columbia River to the west flank of the Gorda Ridge. The age of the upper fining‐upward unit of sandy turbidites appears to correspond to the latest Wisconsinan outburst of glacial Lake Missoula. Many of the outbursts, or jökulhlaups, from the glacial lakes probably continued flowing as hyperpycnally generated turbidity currents on entering the sea at the mouth of the Columbia River.

中文翻译：

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大洋裂谷中的浊积巨床记录了美国西部晚更新世冰川湖的 Jökulhlaups

埃斯卡纳巴海槽是戈尔达海岭的最南端，被局部厚度超过 500 m 的砂质浊积岩充填。大洋钻探计划 (ODP) 站点 1037 和 1038 的新结果，包括加速器质谱 (AMS) 14C 日期和沉积物来源的修订岩相评估，结合高分辨率地震反射剖面，为浊积岩沉积物提供了岩石地层框架. 来自 ODP 站点 1037 上部 365 m 的三个向上细化砂质浊积岩单元可以与在 ODP 站点 1038 和深海钻井计划 (DSDP) 站点 35 回收的沉积物相关联。序列上部 317 m 的六个 AMS 14C 年龄Site 1037 表明平均沉积速率超过 10 m/k.yr。在 32 到 11 ka 之间，几乎瞬时沉积了约 60 米间隔的沙子。沙床的岩相学与 Escanaba 海槽整个沉积层序的哥伦比亚河源一致。高分辨率声学地层显示，Site 1037 上层 60 m 的浊积岩提供了整个 Escanaba 海槽底部发生的关键反射层的特征序列。最近绘制的东北太平洋浊流系统图表明，浊流沿着从哥伦比亚河到戈尔达海岭西侧的 1100 公里长的路径到达埃斯卡纳巴海槽。砂质浊积岩上部细化向上单元的年龄似乎与威斯康星州密苏拉湖最近一次爆发相对应。许多爆发，或 jökulhlaups，