Age determination of sediment core NP90-52 (Table 1)

Data on glacial erosion have been compiled and synthesised using a wide range of sediment budget and sediment yield studies from the Svalbard-Barents Sea region. The data include studies ranging in timescale from 1 to 10**6 yr, and in size of drainage basin from 101 to 105 km**2. They show a clear dependence of sediment yield on the mode of glacierization. Polar glaciers erode at rates comparable to those found in Arctic fluvial basins, or about 40 t/km**-2/ yr or 0.02 mm/yr. In contrast, rates of erosion by polythermal glaciers are 800-1000 t/km**2/ yr (or ca 0.3-0.4 mm/yr), while rates from fast-flowing glaciers are slightly more than twice this: 2100 t/km**2/yr (or 1 mm/yr). Similar rates are also found for large glacierized basins like those in the southwestern parts of the Barents Sea. In contrast to the situation in fluvial basins, in which sediment yield typically decreases with increasing basin size, the tendency in glacierized basins is for erosion to be independent of basin size. In studies of sediment yield from glaciers it is sometimes difficult to distinguish between material actually dislodged from the bedrock by glaciers and material dislodged by other processes in interglacial times and simply transported to a depocenter by a glacier. Our data suggest that pulses of sediment resulting from advance of a glacier over previously-dislodged material last on the order of 10**3 yr, and result in inferred erosion rates that are approximately 25% higher than long-term average rates of glacial erosion. The maximum sediment fluxes from the large Storfjorden and Bear Island drainage basins occurred in mid-Pleistocene. The onset of this period of high sediment yield coincided with the onset of the 100 kyr glacial cycle. We presume that this was the beginning of a period of increased glacial activity, but one in which glaciers still advanced and retreated frequently. During the last two to four 100 kyr cycles, however, sediment yields appear to have decreased. This decrease may be the result of the submergence of the Barents Sea. Glacier erosion would be much higher for a subaerial Barents Sea setting than it would be for a present day subsea Barents Sea. A classical question in Quaternary Geology is whether glaciers are more erosive than rivers. We surmise that if factors such as the lithology and the available potential energy (mgh) of the precipitation falling at a given altitude, whether in liquid or solid form, are held constant, then glaciers are vastly more effective agents of erosion than rivers.本数据集汇编并整合了源自斯瓦尔巴-巴伦支海（Svalbard-Barents Sea）区域的多类沉积物收支（sediment budget）与沉积物产率（sediment yield）研究资料，聚焦冰川侵蚀相关数据。数据涵盖的时间尺度跨度为1年至10^6年，流域面积范围则为10至10^5平方千米。研究结果清晰表明，沉积物产率与冰川作用模式存在显著相关性。极地冰川的侵蚀速率与北极河流流域相当，约为40吨/(平方千米·年)，或0.02毫米/年。与之形成对比的是，多温冰川（polythermal glaciers）的侵蚀速率可达800~1000吨/(平方千米·年)（约合0.3~0.4毫米/年），而快速流动冰川的侵蚀速率则略高于前者的两倍，达到2100吨/(平方千米·年)（或1毫米/年）。巴伦支海南部等大型冰川覆盖流域的侵蚀速率也呈现类似特征。与河流流域的规律不同——后者的沉积物产率通常随流域面积增大而降低——冰川覆盖流域的侵蚀速率几乎不受流域面积影响。在冰川沉积物产率的相关研究中，往往难以区分两类物质：一类是冰川直接从基岩上剥离的物质，另一类是间冰期通过其他过程被搬运、最终由冰川输送至沉积中心（depocenter）的物质。本数据集的分析结果显示，冰川推进至此前已被剥离的物质之上时产生的沉积物脉冲，持续时长约为10^3年，由此推算的侵蚀速率比冰川长期平均侵蚀速率高出约25%。 大型斯托尔峡湾（Storfjorden）与熊岛（Bear Island）流域的最大沉积物通量出现在中更新世时期。该高沉积物产率时期的起始，与10万年冰期循环的启动时间相吻合。我们推测，这标志着冰川活动增强时期的开端，但此时冰川仍处于频繁进退的状态。然而，在过去2至4个10万年冰期循环中，沉积物产率呈现下降趋势。这一下降可能源于巴伦支海的海侵作用：当巴伦支海处于陆相环境时，冰川侵蚀强度远高于现今的海底环境。 第四纪地质学（Quaternary Geology）中的一个经典问题是：冰川的侵蚀能力是否强于河流？我们推测，若保持岩性、特定海拔处降水（无论液态还是固态）的有效势能（mgh，即质量×重力加速度×高度）恒定，那么冰川作为侵蚀营力的效率将远高于河流。