Modification of sediment characteristics during glacial transport in high‐alpine catchments: Mount Cook area, New Zealand
Modification of sediment characteristics during glacial transport in high‐alpine catchments: Mount Cook area, New Zealand
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高山流域冰川运输过程中沉积物特征的改变：新西兰库克山地区
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
W. Ehrmann
中科院分区：
文献类型：
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作者：
M. Hambrey;W. Ehrmann
新西兰南阿尔卑斯山的库克山地区被严重的冰川覆盖，有许多海拔3000米以上的山峰，形成了几个大的山谷冰川。该地区受快速构造隆升和强降水（每年高达15米）的影响。本文从冰川系统的输入、冰川的搬运和冰川沉积后的再加工等方面描述了5个冰川（Fox、Franz Josef、Hooker、Mueller和Tasman）的碎屑圆度、碎屑形状和纹理特征。输入包括岩崩、冲积扇和雪崩物质传递到山谷冰川表面。在两个冰川的末端观察到的基底碎屑主要由合并的河流物质组成。在沉积之后，主要由冰下和前冰流进行改造。主要相为：(1)冰川上方陡坡上以角状碎屑为主的卵石砾石相；(2)以角状和次角状碎屑为主的砂卵石砾石相；(3)以次角状碎屑为主的砂卵石/卵石砾石相；钻石在当代冰川环境中是罕见的。由于大多数与南阿尔卑斯山冰川相关的沉积物缺乏明确的冰川移动迹象，对地质记录中类似沉积物的解释不应必然排除冰川过程的参与。
The Mount Cook area in the Southern Alps of New Zealand is heavily glacierized with numerous peaks over 3000 m a.s.l. feeding several large valley glaciers. The region is subject to rapid tectonic uplift and heavy precipitation (up to 15 m per year). This paper describes the clast roundness, clast shape and textural characteristics associated with five glaciers (Fox, Franz Josef, Hooker, Mueller and Tasman) in terms of inputs to the glacier system, transport by the glaciers and reworking following glacial deposition. Inputs include rockfall, alluvial fan and avalanche material delivered to the surface of valley glaciers. Basal debris, where observed at the terminus of two glaciers, consists mainly of incorporated fluvial material. Following deposition, reworking is mainly by subglacial and proglacial streams. The dominant facies are (i) boulder gravel with mainly angular clasts on the steep slopes above the glaciers, (ii) sandy boulder gravel, with mainly angular and subangular clasts, forming lateral and end moraines, and (iii) sandy boulder/cobble gravel with mainly subrounded clasts, and sand, which represent glacially transported sediment reworked by braided rivers. Diamicton is rare in the contemporary glacial environment. Since most sediment associated with glaciers in the Southern Alps lacks unambiguous indications of glacial transport, interpretation of similar sediments in the geological record should not necessarily exclude the involvement of glacial processes.