This study assesses the spatial and temporal evolution of the glacial landsystem signature at Fjallsjokull, southeast Iceland, using (a) mapping of the glacial geomorphology and surficial geology and (b) repeat uncrewed aerial vehicle (UAV) surveys. A small-scale (1: 15,000 scale) landsystem map has been compiled using LiDAR data (2011−2012) and historical aerial photographs (1945–1998), along with a large-scale (1: 2000 scale) map based on UAV imagery from May 2019. From our mapping and UAV surveys, we identify sediment-landform assemblages that are typical of active temperate glacial landsystems, including recessional push/squeeze moraines and intervening flutings, overridden moraine arcs, proglacial outwash (sandur) fans and linear/ribbon sandar. We recognize three landform zones that are defined by changes in moraine morphology and the nature of proglacial outwash deposition: (1) the outer foreland is characterized by proglacial outwash fans, overridden moraine arcs and broadly linear recessional moraines; (2) the middle foreland contains sawtooth moraines and linear sandar; and (3) the innermost zone comprises extremely sawtooth and hairpin moraines as well as associated crevasse-squeeze ridge limbs. This landform zonation reflects spatio-temporal changes in moraine-forming processes and outwash deposition as determined by changes in snout morphology and proglacial drainage characteristics. Within this general tripartite zonation, we also identify localized (azonal/intrazonal) sediment-landform assemblages that are not typically found at active temperate glaciers, including ice-cored/hummocky terrain and localized kame and kettle topography. Repeat UAV surveying in 2016–2019 has allowed us to capture and quantify recent intrazonal landsystem change at the southern glacier margin. We identify a switch from moraine formation to the development of ice-cored terrain and an ice-cored esker complex in association with the uncovering of a depositional overdeepening. Our study demonstrates the important role that variations in local boundary conditions (e.g. topography) can play in the process-form response of individual active temperate outlet glaciers, contributing to the expanding database on modern glacial landsystems.

中文翻译：

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冰岛 Fjallsjökull 的冰川土地系统：活动温带冰川过程形式制度的时空演变

本研究使用 (a) 冰川地貌和地表地质绘图和 (b) 重复无人驾驶飞行器 (UAV) 调查评估了冰岛东南部 Fjallsjokull 冰川陆地系统特征的空间和时间演变。使用 LiDAR 数据（2011-2012）和历史航拍照片（1945-1998）以及基于无人机图像的大比例（1：2000 比例）地图编制了小比例（1：15,000 比例）陆地系统地图从 2019 年 5 月开始。 从我们的测绘和无人机调查中，我们确定了活动温带冰川土地系统的典型沉积物地貌组合，包括退行性推/挤压碛和介入的槽纹、覆盖的碛弧、前冰期外冲（砂岩）扇和线性/带状桑达尔。我们认识到由冰碛形态变化和前冰外冲沉积性质定义的三个地貌带：（1）外前陆的特征是前冰外冲扇、覆盖冰碛弧和广泛线性的后退冰碛；(2) 中部前陆有锯齿状冰碛和线状砂岩；(3) 最内带包括极锯齿状和发夹状冰碛以及相关的裂隙-挤压脊肢。这种地貌分带反映了碛形成过程和冲刷沉积的时空变化，这是由吻部形态和前冰期排水特征的变化决定的。在这个一般的三方分带中，我们还确定了在活动温带冰川中通常不存在的局部（非带状/带内）沉积物-地貌组合，包括冰芯/丘状地形和局部的kame和水壶地形。2016-2019 年的重复无人机测量使我们能够捕捉和量化南部冰川边缘最近的带内土地系统变化。我们确定了从冰碛形成到冰芯地形发展和冰芯 esker 复合体的转变，这与沉积过度加深的发现有关。我们的研究证明了局部边界条件（例如地形）的变化可以在单个活动温带出口冰川的过程-形式响应中发挥重要作用，有助于扩大现代冰川土地系统的数据库。我们确定了从冰碛形成到冰芯地形发展和冰芯 esker 复合体的转变，这与沉积过度加深的发现有关。我们的研究证明了局部边界条件（例如地形）的变化可以在单个活动温带出口冰川的过程-形式响应中发挥重要作用，有助于扩大现代冰川土地系统的数据库。我们确定了从冰碛形成到冰芯地形发展和冰芯 esker 复合体的转变，这与沉积过度加深的发现有关。我们的研究证明了局部边界条件（例如地形）的变化可以在单个活动温带出口冰川的过程-形式响应中发挥重要作用，有助于扩大现代冰川土地系统的数据库。