Weathering, Blockfields, and Fracture Systems and the Implications for Long-Term Landscape Formation: Some Evidence from Lyngen and Øksfordjøkelen Areas in North Norway
Weathering, Blockfields, and Fracture Systems and the Implications for Long-Term Landscape Formation: Some Evidence from Lyngen and Øksfordjøkelen Areas in North Norway
复制标题
风化、块地和断裂系统以及对长期景观形成的影响：来自挪威北部 Lyngen 和 Øksfordjøkelen 地区的一些证据
DOI：
--
复制
发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Michelle M. Rainey
中科院分区：
文献类型：
--
作者：
W. B. Whalley;B. Rea;Michelle M. Rainey
概述了挪威北部两个山区(约70°N)的基本地貌。该地区有北斯堪的斯古陆表面的遗迹，现在被视为山顶的一致。其中一些山顶有广阔的高原，在那里发现了含有粉尘(约20%)和粘土矿物套件的区块。这些被解释为前冰川时期的风化序列。实验室对一块被移除的岩石的研究表明，没有冻融风化产物，化学风化仅限于节理暴露的表面的外部几毫米。这种风化作用的缺乏归因于完整岩石中微裂缝的稀少。区块生产似乎受到相交裂缝和节理间距的控制，约为米级。粘土堆积和区块深度所需的时间和气候条件表明，前第四纪风化。与斯堪的纳维亚半岛的其他调查相比，这一观点得到了支持。从一个更全面的景观发展的长远观点出发，讨论了前第四纪元素在“冰川”景观中的传承。更新世冰帽未能清除山顶阻塞区的原因是冰冷的冰和/或冰流中的冰被清除，使得覆盖山顶的任何冰在冰川侵蚀中都无效。
The basic geomorphology of two mountain areas in North Norway (ca 70º N) is outlined. The region has remnants of the Palaeic surface of the North Scandes, which are now seen as a summit accordance. Some of these summits have extensive plateaus on which blockfields containing fines (ca. 20%) and suites of clay minerals are found. These have been interpreted as pre-glacial weathering sequences. Laboratory investigations on a block of removed rock show no freeze-thaw weathering products, and chemical weathering is restricted to the outer few millimeters of faces exposed by joints. This lack of weathering is attributed to the paucity of micro-cracks in the intact rock. Block production appears to be controlled by spacing of intersecting cracks and joints at about the meter scale. The time periods and climatic conditions required for the accumulation of clays and the depth of the blockfield points to pre-Quaternary weathering. This view is supported by comparison with other investigations in Scandinavia. The inheritance of the pre-Quaternary elements in a “glacial” landscape is discussed in light of an appreciation of a more holistic long‐term view of landscape development. The failure of Pleistocene ice caps to remove the summit blockfield is attributed to either cold‐based ice and/or the removal of ice in ice streams, leaving any ice covering summits as ineffective in glacial erosion.