The landscapes of the Vallon de la Route and Vallon de Pradieu (France) display typical geomorphological features of the Southern French Alps, with very few or no glaciers but a wide periglacial belt that extends from 2500 to 3100 m a.s.l. These valleys are unusual in that they contain several generations of rock glaciers that, from their rooting zone to their front, have developed in a topoclimatic setting characterised by high mean insolation (southerly aspect) and relatively low altitude. In this work, we determined the present status of these landforms, and more precisely the characteristics of the icy layers within the rock glaciers, via electrical soundings and thermal measurements, which we then combined with field observations. The permafrost zones in both areas are highly fragmented, whereas ground-ice can be present in landforms previously assumed as relict on the basis of their geomorphological characteristics alone. We used an empirical relationship between rock glacier flow velocity and terrain slope to estimate the time needed for both rock glacier assemblages to reach their present size. Our analyses therefore provide at the same time a broad relative chronological framework of the landscape setting up together with an overview of the spatial patterns of ice-rich permafrost features. It also suggests a number of hypotheses for the development of these landforms; however, further work involving more accurate dating methods is required to constrain these hypotheses.
Vallon de la的风景路线和Vallon de Pradieu(法国)显示典型的法国南部阿尔卑斯山脉的地貌特征,很少或根本没有冰川,但大冰缘带扩展了从2500年到3100年m a.s.l。这些山谷是不同寻常的,因为它们包含几代摇滚冰川,从他们的根际面前,已经开发出在topoclimatic环境的特点是高意味着日晒(南风方面)和相对较低的高度。在这项工作中，我们通过电测深和热测量确定了这些地貌的现状，并更准确地确定了岩石冰川内冰层的特征，然后我们将其与实地观测相结合。这两个地区的永久冻土带都是高度破碎的，而地面冰可以存在于以前仅根据其地貌特征就被认为是废弃的地貌中。我们利用岩石冰川流速和地形坡度之间的经验关系来估计这两种岩石冰川组合达到目前规模所需的时间。因此，我们的分析同时提供了景观的一个广泛的相对时间框架，并概述了富冰永久冻土特征的空间格局。它还为这些地貌的发展提出了一些假设;然而，需要进一步的工作，包括更精确的测年方法来约束这些假设。
{"title":"Present status and development of rock glacier complexes in south-faced valleys (45°N, French Alps)","authors":"Xavier Bodin","doi":"10.4461/GFDQ.2013.36.2","DOIUrl":"https://doi.org/10.4461/GFDQ.2013.36.2","url":null,"abstract":"The landscapes of the Vallon de la Route and Vallon de Pradieu (France) display typical geomorphological features of the Southern French Alps, with very few or no glaciers but a wide periglacial belt that extends from 2500 to 3100 m a.s.l. These valleys are unusual in that they contain several generations of rock glaciers that, from their rooting zone to their front, have developed in a topoclimatic setting characterised by high mean insolation (southerly aspect) and relatively low altitude. In this work, we determined the present status of these landforms, and more precisely the characteristics of the icy layers within the rock glaciers, via electrical soundings and thermal measurements, which we then combined with field observations. The permafrost zones in both areas are highly fragmented, whereas ground-ice can be present in landforms previously assumed as relict on the basis of their geomorphological characteristics alone. We used an empirical relationship between rock glacier flow velocity and terrain slope to estimate the time needed for both rock glacier assemblages to reach their present size. Our analyses therefore provide at the same time a broad relative chronological framework of the landscape setting up together with an overview of the spatial patterns of ice-rich permafrost features. It also suggests a number of hypotheses for the development of these landforms; however, further work involving more accurate dating methods is required to constrain these hypotheses.","PeriodicalId":49250,"journal":{"name":"Geografia Fisica E Dinamica Quaternaria","volume":"36 1","pages":"27-28"},"PeriodicalIF":0.4,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70970601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：