Landforms produced beneath former ice sheets offer insights into inaccessible subglacial processes and present analogues for how current ice masses may evolve in a warming climate. Large subglacial channels cut by meltwater erosion (tunnel valleys [TVs]) have the potential to provide valuable empirical constraints for numerical ice-sheet models concerning realistic melt rates, water routing, and the interplay between basal hydrology and ice dynamics. However, the information gleaned from these features has thus far been limited by an inability to adequately resolve their internal structures. We use high-resolution three-dimensional (HR3-D) seismic data (6.25 m bin size, ∼4 m vertical resolution) to analyze the infill of buried TVs in the North Sea. The HR3-D seismic data represent a step-change in our ability to investigate the mechanisms and rates at which TVs are formed and filled. Over 40% of the TVs examined contain buried glacial landforms including eskers, crevasse-squeeze ridges, glacitectonic structures, and kettle holes. As most of these landforms had not previously been detected using conventional 3-D seismic reflection methods, the mechanisms that formed them are currently absent from models of TV genesis. The ability to observe such intricate internal structures opens the possibility of using TVs to reconstruct the hydrological regimes of former mid-latitude ice sheets as analogues for contemporary ones.Throughout the Quaternary, the growth and retreat of ice sheets across high- and mid-latitude continental shelves drove major changes to topographic relief and global sea level (e.g., Batchelor et al., 2019). Subglacial water flow to the margins of these ice sheets excavated huge channels, kilometers wide and hundreds of meters deep, which are referred to as tunnel valleys (TVs) (ÓCofaigh, 1996; Huuse and Lykke-Andersen, 2000; Kehew et al., 2012). Multiple cross-cutting generations of TVs, potentially correlated with seven glacial cycles, are buried beneath the seafloor in the North Sea (Kristensen et al., 2007; Stewart and Lonergan, 2011). TVs provide a unique opportunity to investigate the subglacial plumbing system of the ice sheets that formerly covered northwestern Europe and to learn more about inaccessible basal processes that regulate ice-sheet flow and retreat. However, there is currently no consensus on the timescales and mechanisms through which glacial meltwater forms TVs or their impact on ice-sheet dynamics, and theories about their formation range between rapid erosion during catastrophic floods to gradual development through multiple incision events (Kehew et al., 2012). The infill of TVs is similarly complex; some models propose that TVs were cut and filled incrementally (e.g., Jørgensen and Sandersen, 2006), while others favor simultaneous cutting and infilling in a conveyor-like fashion tracking ice front recession (Praeg, 2003; Kristensen et al., 2008). Disagreement over TV infill reflects spatial heterogeneity in TV form and sedimentary composition in outcrops, a scarcity of borehole samples, and data resolution constraints that limit the extent to which their internal architecture can be analyzed in three dimensions (3-D; Huuse and Lykke-Andersen, 2000; Praeg, 2003). We use novel high-resolution 3-D (HR3-D) seismic data from the North Sea to examine the infill of TVs in unprecedented detail and discuss the implications for TV genesis.We examined six HR3-D seismic data sets, covering ∼60 km2, from the central North Sea (Figs. 1A and 1B). The acquisition system comprised two 1200-m-long streamers towed 3 m beneath the sea surface with 96 hydrophone groups at 12.5 m spacing, a 6.25 m shot interval, and a 1 ms sample rate (Games, 2012). The seismic source consisted of two 160 in3 sleeve air gun clusters with a 20–250 Hz signal frequency. Data processing included swell noise attenuation, tide correction, multiple suppression, two passes of velocity analyses run at 250 × 250 m intervals, normal moveout correction, and bandpass filtering. The final processed data sets consist of time-migrated 3-D stacks with a 1 ms sample rate, a 6.25 × 6.25 m bin size, a vertical resolution of ∼4 m, and a detection limit along individual reflectors of ∼0.5 m. In comparison, the 3-D seismic data previously used to examine TVs in this region typically have bin sizes of 12.5–50 m and a vertical resolution of ∼8–16 m (Stewart et al., 2013). Depth conversions used a velocity of 1800 m s−1 (Stoker et al., 1985).The six HR3-D seismic data sets image 19 cross-cutting incisions that are 300–3000 m wide, up to 300 m deep, and possess undulating thalwegs. We interpret these as TVs formed by subglacial meltwater based on their distinctive morphology (e.g., Stewart et al., 2013). The TVs contain between one to four discrete fill units, and most consist of two seismic facies. The infill is highly variable and lacks consistent patterning between each TV, although some common facies are present (Figs. 1C and 1D). Over 50% of the TVs contain a chaotic, largely homogenous fill package that often overtops the TV shoulders. We interpret this facies as subaqueous or subaerial outwash. In addition, the lowermost facies of ∼60% of TVs contains discontinuous sub-parallel reflections that are interpreted as clays and sands deposited in a subglacial or proglacial subaqueous setting. We estimate that twice the number of infill units can be resolved in our HR3-D seismic data compared to conventional 3-D seismic data; this improvement represents a step-change in our ability to observe fine-scale TV infill structures (Fig. 2).Several TVs contain high-amplitude reflections between their upper and lower fill units. When mapped in 3-D, these reflections delineate sinuous ridges that are up to 2.8 km long, 30–150 m wide, and 5 m high on average (Fig. 3A). Based on their morphological similarity to features elsewhere (e.g., Storrar et al., 2014; see Fig. S1 in the Supplemental Material1), we interpret the ridges as eskers that were deposited in meltwater conduits present at the base of an ice sheet.Small hollows containing well-layered fill are observed buried within the outwash unit that caps some TVs. The hollows are 100–300 m wide, 200–750 m long and have side slopes of 10–35° (Figs. 3B and 3F). We interpret the hollows as kettle holes that formed when stagnant ice blocks were stranded in shallow water (e.g., Ottesen et al., 2017). Their well-layered internal structure likely reflects infilling with fine-grained sediments once the ice blocks melted in place or floated off in a marine setting.Subtle ridge patterns of two morphologies are buried within the TVs and appear as undulating reflections with high acoustic amplitude. The features form irregular networks of four- to six-sided polygons that are rhombohedral in planform morphology, 40–80 m in diameter, and slightly hollow in the center. Individual ridges are 20–250 m long, 20–30 m wide, and <4 m high from base to crest (Figs. 3C and 3G). Several processes have been documented to produce rhombohedral ridges, including fluid escape, diagenesis, glacier surging, and permafrost processes (e.g., Ottesen and Dowdeswell, 2006; Morley et al., 2017; Bellwald et al., 2019). We rule out fluid escape due to the absence of visible chimneys or pipes above the features and suggest that substantial diagenetic change is unlikely to occur at such shallow depths (<250 m below seabed). The fact that the ridges are confined to the TV rather than extending onto the surrounding banks, combined with their irregular rims, suggests these landforms do not result from permafrost processes. Rather, based on their morphological similarity to features on glaciated terrains elsewhere (Ottesen and Dowdeswell (2006); Fig. S2), we interpret these landforms as crevasse-squeeze ridges that formed through sediment injection upwards into basal fractures beneath grounded ice (Rea and Evans, 2011; Evans et al., 2016).Groups of sub-parallel curvilinear ridges, commonly located in the upper third of TV infill, constitute the second type of ridge pattern (Fig. 3D). The symmetrical ridges are spaced 50–100 m apart, 100–300 m long, <3 m high, terminate sharply, and are oriented perpendicular to the long axis of the TVs (Fig. 3D). We interpret these as crevasse-squeeze ridges formed as grounded ice retreated through the TVs.Distinctive features are also found at the base of the TVs in the form of networks of anabranching channels (80 m wide and ∼6 m deep on average) incised around streamlined bars 55–540 m long and 30–165 m wide (Fig. 3E). The thalweg of the TV displayed in Figure 3E undulates, which suggests a subglacial rather than subaerial fluvial origin. Several TVs also contain chaotic and displaced reflections along the sides and bases, which we interpret as evidence of slumping, faulting, and glacitectonic thrusting (Figs. 1D and 3H).Over 40% of the TVs examined here contain buried landforms of glacial origin (Fig. 3). Most of these features are too small to interpret using conventional 3-D seismic data and would be difficult to detect using 2-D seismic data or boreholes alone (Fig. 2). Accordingly, glacial landforms, both erosional and depositional in nature, are likely far more common inside TVs than previously recognized.The ice sheets formerly occupying the North Sea Basin were underlain by thick sequences of flat-lying unconsolidated sediments. In such settings, subglacial water is thought to be transported in networks of broad and shallow sedimentary channels (Walder and Fowler, 1994) that may resemble the braided channels observed at the base of some TVs (Fig. 3E). Braided channel systems may be eroded into the substrate surrounding a subglacial conduit when the latter drainage system is temporarily overwhelmed by pulses of meltwater supplied from the ice sheet surface (Fig. 4A; Lewington et al., 2020). This could be achieved by supraglacial lake drainage via hydrofracture (e.g., Das et al., 2008). Repeated transfer of surface meltwater to the bed, coupled with lateral enlargement by overriding ice, would gradually excavate a TV and induce glacitectonic deformation structures and mass movements along its sides (Fig. 3H); these processes have also been inferred from TVs exposed in sections of Late Ordovician glaciogenic rocks (Hirst et al., 2002; Le Heron et al., 2004).Although eskers have been documented along the base of unfilled subaerial TVs in North America (e.g., Brennand and Shaw, 1994), these features are rarely reported inside filled TVs (van der Vegt et al., 2012). Traditionally, eskers and TVs are thought to seldom coexist, as eskers are associated mainly with hard bed substrates while TVs form in poorly consolidated sediments (Clark and Walder, 1994; Huuse and Lykke-Andersen, 2000). The eskers observed within the TVs here indicate that this association probably reflects the poor preservation potential of eskers on soft substrates (Storrar et al., 2019). The near-central stratigraphic position of the eskers within the TV infill is significant, as it demonstrates that grounded ice occupied the TV until the channel filled to approximately half of its accommodation space, which implies significantly greater longevity of ice occupation than was assumed in previous models of TV genesis (van der Vegt et al., 2012). It is possible that eskers in the TVs represent the final sedimentary cast of migrating meltwater conduits that were filled during the last stages of deglaciation under a thinning ice-sheet terminus (Storrar et al., 2014; Beaud et al., 2018). Lateral continuity and a high degree of esker preservation implies gradual ice retreat from these TVs and precludes reworking by ice readvances before the eskers were buried by outwash sediments. As esker continuity reflects the ice dynamics at the time they were formed (Storrar et al., 2014), further investigation into the degree of esker fragmentation within TVs may hint at the style and rate of past ice-sheet retreat (Livingstone et al., 2020).Crevasse-squeeze ridges are diagnostic of surging glaciers (Sharp, 1985). These features form at the termination of a surge through sediment injection into basal crevasses and are preserved by the stagnation and in situ downwasting of the overlying ice (Rea and Evans, 2011). Kettle holes can also form from ice stagnation and meltout during the quiescent phase of tidewater glacier surges (Ottesen et al., 2017).The presence of landforms indicative of glacier surging within some TVs may imply that they acted as conduits for fast ice flow prior to being fully infilled. The absence of these landforms beyond the TVs indicates that either surges were confined to the TVs due to hydrological factors that initiated the fast flow or that such delicate features were not preserved outside of the TVs. Experiments with silicon models of the subglacial hydrological system demonstrate that TV formation often coincides with surges in the velocity of the model glacier that are triggered by increases in basal water pressure, causing the ice to decouple from its bed (Lelandais et al., 2016). The glacial landforms observed here support a link between the transport of water in TVs and dynamic ice behavior.The variety of landform assemblages preserved inside the cross-cutting TVs hints at the diverse ice-sheet regimes that formed and filled them. Our HR3-D seismic data suggest that TVs were incised gradually by migrating meltwater channels driven by pulses of meltwater from the ice-sheet surface (Fig. 4A) and were enlarged by ice flow, which induced deformation structures and mass movements along their sides (Prins et al., 2020) (Fig. 4B). Gradual ice retreat from TVs may fill and preserve the most recently active channels as laterally continuous eskers (Fig. 4C), while dynamic ice flow through the TVs, possibly as surges or readvances, followed by stagnation and downwasting, may be indicated by the presence and preservation of crevasse-squeeze ridges and kettle holes (Fig. 4D).Our study marks the first time that abundant glacial landforms have been convincingly imaged within buried TVs in the North Sea. The presence of eskers and crevasse-squeeze ridges within the mid–upper TV fill packages demonstrates that grounded ice played an active role in TV incision and was present for a substantial time during filling. For these delicate landforms to have been preserved in the geological record, reoccupation of the TVs between different glacial cycles must have been limited, although localized ice readvances may have occurred. This result constrains the formation and infilling of each TV generation to a single glaciation and supports the notion that the multiple generations of TVs present in the North Sea record at least seven glacial advances across northwestern Europe (Stewart and Lonergan, 2011). Greater coverage of HR3-D seismic data on glaciated margins, combined with chronological constraints from shallow drilling, may permit TVs to become a resource to improve understanding of the hydrological systems and dynamics of former ice sheets.We thank bp, Harbour Energy, Equinor Energy AS, Lundin Energy Norway AS, Petoro AS, Aker BP ASA, Total E&P Norge AS, and Petroleum Geo-Services for permission to publish images from the HR3-D seismic data and the Central North Sea MegaSurveyPlus. IHS and Schlumberger provided academic seismic interpretation software licenses. J. Kirkham is supported by Natural Environment Research Council grant NE/L002507/1. This research is supported by the British Antarctic Survey Polar Science for Planet Earth programme. The interpretations made in this paper are the views of the authors and not necessarily those of the license owners. Sean Gulick, Benjamin Bellwald, and Brian Todd are thanked for helpful reviews.

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高分辨率 3-D 地震数据揭示的隧道谷填充和成因

前冰盖下产生的地貌提供了对难以接近的冰下过程的见解，并提供了当前冰块如何在气候变暖中演变的类似物。被融水侵蚀切割的大型冰下通道（隧道山谷 [TVs]）有可能为有关实际融化速率、水流路线以及基础水文和冰动力学之间相互作用的数值冰盖模型提供有价值的经验约束。然而，迄今为止，从这些特征中收集到的信息由于无法充分解析其内部结构而受到限制。我们使用高分辨率三维 (HR3-D) 地震数据（6.25 m bin 大小，~4 m 垂直分辨率）来分析北海埋藏电视的填充物。HR3-D 地震数据代表了我们研究 TV 形成和填充的机制和速率的能力的一个阶跃变化。超过 40% 的被检查电视包含掩埋的冰川地貌，包括 eskers、裂缝挤压脊、冰川构造结构和壶洞。由于这些地形中的大多数以前没有使用传统的 3-D 地震反射方法检测到，因此形成它们的机制目前在电视成因模型中不存在。观察如此复杂的内部结构的能力为使用电视重建前中纬度冰盖的水文状况作为当代冰盖的类似物提供了可能性。跨越高纬度和中纬度大陆架的冰盖的增长和消退推动了地形起伏和全球海平面的重大变化（例如，Batchelor 等，2019）。流向这些冰盖边缘的冰下水流挖出了数公里宽、数百米深的巨大通道，这些通道被称为隧道山谷 (TV)（ÓCofaigh，1996 年；Huuse 和 Lykke-Andersen，2000 年；Khew 等人， 2012）。可能与七个冰川周期相关的多代横切电视被埋在北海的海底之下（Kristensen 等，2007；Stewart 和 Lonergan，2011）。电视提供了一个独特的机会来研究以前覆盖欧洲西北部的冰盖的冰下管道系统，并了解更多关于调节冰盖流动和退缩的难以接近的基础过程。然而，目前对于冰川融水形成 TV 的时间尺度和机制或其对冰盖动力学的影响，以及它们的形成范围从灾难性洪水期间的快速侵蚀到通过多次切口事件逐渐发展之间的理论尚未达成共识（Kehew 等人., 2012)。电视的填充也同样复杂；一些模型建议电视逐渐切割和填充（例如，Jørgensen 和 Sandersen，2006），而其他模型则倾向于在类似传送带的时尚追踪冰前衰退中同时切割和填充（Praeg，2003；Kristensen 等，2008）。对 TV 填充的分歧反映了 TV 形式的空间异质性和露头的沉积成分，钻孔样品的稀缺，和数据分辨率约束限制了其内部架构可以在三个维度上进行分析的程度（3-D；Huuse 和 Lykke-Andersen，2000 年；Praeg，2003 年）。我们使用来自北海的新型高分辨率 3-D (HR3-D) 地震数据，以前所未有的细节检查 TV 的填充，并讨论对 TV 成因的影响。 我们检查了六个 HR3-D 地震数据集，涵盖 ∼60 km2，来自北海中部（图 1A 和 1B）。采集系统包括两条 1200 米长的拖缆，拖曳在海面以下 3 m 处，带有 96 个水听器组，间距为 12.5 m，发射间隔为 6.25 m，采样率为 1 ms（Games，2012）。震源由两个 160 英寸 3 套筒气枪组组成，信号频率为 20-250 Hz。数据处理包括涌浪噪声衰减、潮汐校正、多重抑制、两次速度分析以 250 × 250 米的间隔运行，正常时差校正和带通滤波。最终处理的数据集由时间偏移的 3-D 堆栈组成，采样率为 1 ms，箱大小为 6.25 × 6.25 m，垂直分辨率约为 4 m，沿单个反射器的检测限约为 0.5 m。相比之下，以前用于检查该地区 TV 的 3-D 地震数据通常具有 12.5-50 m 的区间大小和~8-16 m 的垂直分辨率（Stewart 等，2013）。深度转换使用 1800 ms-1 的速度（Stoker 等人，1985 年）。六个 HR3-D 地震数据集成像了 19 个横切切口，这些切口宽 300-3000 m，深达 300 m，并且具有起伏thalwegs。我们根据它们独特的形态将这些解释为由冰下融水形成的 TV（例如，Stewart 等，2013）。TVs 包含一到四个离散的填充单元，大多数由两个地震相组成。尽管存在一些常见的相（图 1C 和 1D），但填充物变化很大，每台电视之间缺乏一致的图案。超过 50% 的电视包含一个混乱的、基本同质的填充包，经常超出电视的肩膀。我们将这种相解释为水下或地面冲刷。此外，约 60% 的 TV 的最下部相包含不连续的亚平行反射，这些反射被解释为沉积在冰下或冰前水下环境中的粘土和沙子。我们估计，与传统的 3-D 地震数据相比，我们的 HR3-D 地震数据可以解析两倍数量的填充单元；这种改进代表了我们观察精细电视填充结构的能力的一个阶跃变化（图 2）。一些电视在其上下填充单元之间包含高振幅反射。当以 3-D 方式绘制地图时，这些反射描绘了长达 2.8 公里、宽 30-150 米、平均高 5 米的蜿蜒山脊（图 3A）。基于它们与其他地方特征的形态相似性（例如，Storrar 等人，2014 年；参见补充材料 1 中的图 S1），我们将这些山脊解释为沉积在冰盖底部融水管道中的 eskers。小观察到包含分层填充物的空洞被埋在一些电视上的冲洗单元内。空心宽 100-300 m，长 200-750 m，边坡为 10-35°（图 3B 和 3F）。我们将空洞解释为当停滞的冰块搁浅在浅水中时形成的水壶洞（例如，Ottesen 等，2017）。一旦冰块就地融化或漂浮在海洋环境中，它们分层良好的内部结构可能会反映出细粒沉积物的填充。两种形态的微妙山脊图案被埋在电视内，并表现为具有高声波振幅的起伏反射。这些特征形成了四到六边形的不规则多边形网络，这些多边形在平面形态上为菱形，直径为 40-80 m，中心略有空心。单个山脊长 20-250 m，宽 20-30 m，从底部到顶部的高度 <4 m（图 3C 和 3G）。已经记录了几种产生菱形山脊的过程，包括流体逃逸、成岩作用、冰川涌动和永久冻土过程（例如，Ottesen 和 Dowdeswell，2006 年；Morley 等人，2017 年；Bellwald 等人，2019 年）。由于在特征上方没有可见的烟囱或管道，我们排除了流体逃逸的可能性，并表明在如此浅的深度（海床以下 <250 m）不太可能发生实质性的成岩变化。山脊仅限于电视而不是延伸到周围的河岸，再加上不规则的边缘，这表明这些地貌不是由永久冻土过程造成的。相反，基于它们与其他地方的冰川地形特征的形态相似性（Ottesen 和 Dowdeswell（2006）；图 S2），我们将这些地貌解释为裂缝挤压山脊，这些山脊是通过沉积物向上注入接地冰下的基底裂缝而形成的（Rea 和Evans, 2011; Evans et al., 2016). 亚平行曲线脊群，通常位于电视填充物的上三分之一处，构成第二种类型的脊图案（图 3D）。对称的脊间隔 50-100 m，长 100-300 m，高 <3 m，末端尖锐，并垂直于 TV 的长轴定向（图 3D）。我们将这些解释为当接地的冰通过 TV 后退时形成的裂缝挤压脊。 在​​ TV 的底部也发现了鲜明的特征，即在周围切割的分枝通道网络（80 m 宽，平均约 6 m 深）流线型钢筋长 55-540 m，宽 30-165 m（图 3E）。图 3E 中显示的电视的 thalweg 呈波浪状，这表明是冰下而不是地下河流起源。几个 TV 还包含沿侧面和底部的混乱和位移反射，我们将其解释为坍塌、断层和冰川构造推力的证据（图 1D 和 3H）。此处检查的 40% 以上的电视包含冰川成因的掩埋地貌（图 3）。大多数这些特征太小而无法使用传统的 3-D 地震数据进行解释，并且很难单独使用 2-D 地震数据或钻孔进行检测（图 2）。因此，自然侵蚀和沉积的冰川地貌在电视内可能比以前认识的要常见得多。以前占据北海盆地的冰盖下面是厚厚的平坦松散沉积物序列。在这种情况下，冰下水被认为是在宽而浅的沉积通道网络中传输的（Walder 和 Fowler，1994），这可能类似于在某些电视底部观察到的编织通道（图 3E）。当冰下排水系统暂时被冰盖表面提供的融水脉冲淹没时，编织通道系统可能会被侵蚀到围绕冰下管道的基底中（图 4A；Lewington 等，2020）。这可以通过水力压裂的冰上湖排水来实现（例如，Das 等，2008）。地表融水反复转移到床层，加上上覆冰的横向扩大，将逐渐挖掘出一个 TV 并引发冰川变形结构和沿其两侧的质量运动（图 3H）；这些过程也可以从晚奥陶世冰川成因岩部分中暴露的 TV 推断出来（Hirst 等人，2002 年；Le Heron 等人，2004 年）。尽管 eskers 已被记录在北美未填充的地下 TVs 底部（例如, 布伦南德和肖, 1994), 这些特征很少在填充电视中报道（van der Vegt 等，2012）。传统上，eskers 和 TVs 被认为很少共存，因为 eskers 主要与硬床基质相关，而 TVs 形成于固结差的沉积物（Clark 和 Walder，1994 年；Huuse 和 Lykke-Andersen，2000 年）。此处电视中观察到的 eskers 表明这种关联可能反映了 eskers 在软基材上的较差的保存潜力（Storrar 等，2019）。电视填充物内 eskers 的近中央地层位置很重要，因为它表明接地的冰占据了电视，直到频道填充到其容纳空间的大约一半，这意味着冰占据的寿命比之前假设的要长得多电视起源模型（van der Vegt et al., 2012）。TVs 中的 eskers 可能代表了迁移融水管道的最终沉积模型，这些管道在冰盖变薄的最后阶段被填满（Storrar 等人，2014 年；Beaud 等人，2018 年）。横向连续性和高度的 esker 保存意味着冰从这些 TV 中逐渐撤退，并阻止在 esker 被外冲沉积物掩埋之前通过冰层重新进行再加工。由于 esker 连续性反映了它们形成时的冰动态（Storrar 等人，2014），对电视中 esker 碎片程度的进一步调查可能暗示过去冰盖退缩的风格和速度（Livingstone 等人，2014 年）。 , 2020。裂隙挤压山脊是冰川涌动的诊断依据（Sharp, 1985）。这些特征在通过沉积物注入基底裂缝的浪涌终止时形成，并通过上覆冰的停滞和原位下沉而得以保留（Rea 和 Evans，2011）。在潮水冰川浪涌的静止阶段，冰的停滞和融化也可能形成水壶洞（Ottesen 等人，2017 年）。某些电视中指示冰川浪涌的地貌的存在可能意味着它们在之前充当了快速冰流的管道到完全填充。电视之外没有这些地貌表明，要么由于引发快速流动的水文因素而将浪涌限制在电视上，要么在电视外没有保留这种微妙的特征。冰下水文系统硅模型的实验表明，TV 的形成通常与模型冰川的速度激增同时发生，这是由基础水压增加引发的，导致冰与其床解耦（Lelandais 等人，2016 年） . 这里观察到的冰川地貌支持了 TV 中水的传输与动态冰行为之间的联系。在横切 TV 内保存的各种地形组合暗示了形成和填充它们的不同冰盖状态。我们的 HR3-D 地震数据表明，TV 是通过迁移由来自冰盖表面的融水脉冲驱动的融水通道逐渐切开的（图 4A），并被冰流扩大，从而引起变形结构和沿其侧面的质量运动（ Prins 等人，2020 年）（图 4B）。从电视上逐渐消退的冰可能会填充并保留最近活跃的频道作为横向连续的 eskers（图 4C），而通过电视的动态冰流，可能作为浪涌或重新上升，随后是停滞和向下浪费，可能由存在表明以及裂缝挤压脊和壶洞的保存（图 4D）。我们的研究标志着第一次在北海的埋藏电视中对丰富的冰川地貌进行了令人信服的成像。中上部 TV 填充包中存在 eskers 和裂缝挤压脊表明接地冰在 TV 切口中发挥了积极作用，并且在填充过程中存在很长时间。这些微妙的地貌要保存在地质记录中，不同冰川周期之间电视的重新占用肯定是有限的，尽管可能发生了局部的冰读取。这一结果将每一代电视的形成和填充限制在单一冰川，并支持北海多代电视记录了欧洲西北部至少七次冰川进展的观点（Stewart 和 Lonergan，2011）。冰川边缘 HR3-D 地震数据的更大覆盖范围，结合浅层钻井的时间限制，可能使 TV 成为一种资源，以提高对水文系统和前冰盖动力学的了解。我们感谢 bp、Harbour Energy、Equinor Energy AS、Lundin Energy Norway AS、Petoro AS、Aker BP ASA、Total E&P Norge AS 和 Petroleum Geo-Services 获准发布来自 HR3-D 地震数据和北海中部 MegaSurveyPlus 的图像。IHS 和 Schlumberger 提供了学术地震解释软件许可。J. Kirkham 得到自然环境研究委员会资助 NE/L002507/1 的支持。这项研究得到了英国南极调查地球极地科学计划的支持。本文中的解释是作者的观点，不一定是许可证所有者的观点。感谢 Sean Gulick、Benjamin Bellwald 和 Brian Todd 提供的有益评论。