Climate warming in Svalbard since the end of the ‘Little Ice Age’ early in the 20th century has reduced glacier extent in the archipelago. Previous attempts to reconstruct ‘Little Ice Age’ glacier limits have encountered problems in specifying the area of tidewater glacier advances because it is difficult to estimate the past positions of their marine termini. Multibeam echo-sounding data are needed to map past glacier extent offshore, especially in open-marine settings where subaerial lateral moraines cannot be used due to the absence of fjord walls. We use the submarine glacial landform record to measure the recent limits of advance of over 30 marine-terminating northeastern Svalbard glaciers and ice caps. Our results demonstrate that previous work has underestimated the ice-covered area relative to today by about 40% for northeastern Svalbard (excluding southeast Austfonna) because marine-geophysical evidence in the form of submarine terminal moraines was not included. We show that the recent ice extent was 1753 km2 larger than today over our full area of multibeam data coverage; about 5% of the total modern ice cover of Svalbard. It has often been assumed that moraine ridges located within a few kilometres of modern ice fronts in Svalbard represent either a ‘Little Ice Age’ maximum or relate to surge activity over the past century or so. In the marine environment of northeastern Svalbard, this timing can often be confirmed by reference to early historical maps and aerial photographs. Assemblages of submarine glacial landforms inshore of recently deposited terminal moraines suggest whether a recent advance may be a result of surging or ‘Little Ice Age’ climatic cooling relative to today. However, older terminal moraines do exist in the archipelago, as shown by radiocarbon and 10Be dating of Holocene moraine ridges.

中文翻译：

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来自海洋地球物理记录的“小冰河时代”以来斯瓦尔巴东北部海洋终止冰川和冰盖的变化范围

自 20 世纪初“小冰河时代”结束以来，斯瓦尔巴群岛的气候变暖已经减少了该群岛的冰川范围。先前重建“小冰河时代”冰川界限的尝试在指定潮水冰川前进的区域时遇到了问题，因为很难估计其海洋终点的过去位置。需要多波束回波探测数据来绘制离岸冰川范围的地图，特别是在开放海洋环境中，由于没有峡湾壁而无法使用地下侧碛。我们使用海底冰川地貌记录来测量 30 多个终止于海洋的斯瓦尔巴群岛东北部冰川和冰盖的近期推进极限。我们的结果表明，由于未包括海底终端冰碛形式的海洋地球物理证据，以前的工作相对于今天的斯瓦尔巴群岛东北部（不包括东南部）的冰覆盖面积低估了约 40%。我们表明，在我们多波束数据覆盖的整个区域内，最近的冰范围比今天大 1753 平方公里；约占斯瓦尔巴现代冰盖总量的 5%。人们通常认为，位于斯瓦尔巴群岛现代冰锋几公里内的碛脊要么代表“小冰河时代”的最大值，要么与过去一个世纪左右的海浪活动有关。在斯瓦尔巴群岛东北部的海洋环境中，这个时间往往可以通过参考早期历史地图和航拍照片来确认。最近沉积的终端冰碛近海海底冰川地貌的组合表明，最近的进展是否可能是相对于今天的激增或“小冰河时代”气候变冷的结果。然而，如全新世冰碛脊的放射性碳和 10Be 测年所示，群岛中确实存在较旧的终端冰碛。