...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >The dynamics of mountain erosion: Cirque growth slows as landscapes age
【24h】

The dynamics of mountain erosion: Cirque growth slows as landscapes age

机译：山区侵蚀的动态：景观年龄的大小增长减缓

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Glacial cirques are widely used palaeoenvironmental indicators, and are key to understanding the role of glaciers in shaping mountain topography. However, notable uncertainty persists regarding the rate and timing of cirque erosion. In order to address this uncertainty, we analyse the dimensions of 2208 cirques in Britain and Ireland and model ice accumulation to investigate the degree of coupling between glacier occupation times and cirque growth. Results indicate that during the last similar to 120 ka, cirques were glacier-free for an average of 52.0 +/- 21.2 ka (43 +/- 18%); occupied by small (largely cirque-confined) glaciers for 16.2 +/- 9.9 ka (14 +/- 8%); and occupied by large glaciers, including ice sheets, for 51.8 +/- 18.6 ka (43 +/- 16%). Over the entire Quaternary (i.e. 2.6 Ma), we estimate that cirques were glacier-free for 1.1 +/- 0.5 Ma; occupied by small glaciers for 0.3 +/- 0.2 Ma; and occupied by large glaciers for 1.1 +/- 0.4 Ma. Comparing occupation times to cirque depths, and calculating required erosion rates, reveals that continuous cirque growth during glacier occupation is unlikely. Instead, we propose that cirques attained much of their size during the first occupation of a non-glacially sculpted landscape (perhaps during the timeframe of a single glacial cycle). During subsequent glacier occupations, cirque growth may have slowed considerably, with the highest rates of subglacial erosion focused during periods of marginal (small glacier) glaciation. We propose comparatively slow rates of growth following initial cirque development because a 'least resistance' shape is formed, and as cirques deepen, sediment becomes trapped subglacially, partly protecting the bedrock from subsequent erosion. In support of the idea of rapid cirque growth, we present evidence from northern British Columbia, where cirques of comparable size to those in Britain and Ireland developed in less than 140 ka. (c) 2019 John Wiley & Sons, Ltd.
机译：冰川CirceS是广泛使用的古环境指标，并是了解冰川在塑造山地地形中的作用的关键。然而，关于腐蚀的速度和时间，显着的不确定性。为了解决这种不确定性，我们分析英国和爱尔兰2208个CirQues的尺寸，并模拟冰积累，以研究冰川占用时间和致敏生长之间的耦合程度。结果表明，在最后类似至120ka期间，CirQues平均冰川冰川冰川（43 +/- 18％）;由小（基本上狭窄）冰川占用16.2 +/- 9.9 Ka（14 +/- 8％）;由大型冰川占据，包括冰盖，51.8 +/- 18.6 Ka（43 +/- 16％）。在整个第四纪（即2.6 mA）中，我们估计Cirques是无冰川的1.1 +/- 0.5 mA;由小冰川占用0.3 +/- 0.2 mA;由大型冰川占据1.1 +/- 0.4 mA。将占用时间与巫经深度进行比较，并计算所需的侵蚀率，揭示了冰川占领期间的连续旋律增长不太可能。相反，我们提出了在第一次占用非冰冷雕刻的景观期间达到了大部分大小（在单个冰川周期的时间范围内）。在随后的冰川职业期间，Cirque Grower可能会显着放缓，具有在边缘（小冰川）冰川期间聚焦的沉淀侵蚀的最高速率。我们提出了初始Cirque开发后的增长比较缓慢，因为形成了“最小阻力”形状，并且随着Circiques加深，沉积物被捕获沉淀，部分保护基岩从随后的侵蚀。为了支持快速的Cirque成长的想法，我们提出了来自不列颠哥伦比亚州北部的证据，其中与英国和爱尔兰的相当规模的Circiques在不到140 ka的情况下发展。 （c）2019 John Wiley＆Sons，Ltd。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号