Southern Carpathian rock glaciers: Inventory, distribution and environmental controlling factors

Onaca, Alexandru; Ardelean, Florina; Urdea, Petru; Magori, Brigitte

doi:10.1016/j.geomorph.2016.03.032

Cited by 46 publications

(30 citation statements)

References 54 publications

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“…Compared with the MARGs, the TARGs are more evenly distributed across all aspects. This pattern is consistent with that found in rock glaciers in the central Italian Alps and Southern Carpathians (Scotti et al, 2013;Onaca et al, 2016).…”

Section: General Statistics Of the Inventorysupporting

confidence: 91%

“…Many studies have used active and inactive rock glaciers to map local-scale indicators of permafrost occurrence in major mountain ranges such as the European Alps, the Rocky Mountains, the Andes, and the Hindu Kush Himalayan region (e.g., Barsch, 1996;Janke, 2005;Brenning and Trombotto, 2006;Boeckli et al, 2012;Bollmann et al, 2015;Schmid et al, 2015). However, it is difficult to assess the kinematic status of rock glaciers directly (either from the field or remote sensing) and therefore challenging to distinguish active and inactive rock glaciers (Onaca et al, 2016;Sattler et al, 2016). If one only uses ARGs, it would be more accurate and robust to infer the permafrost distribution (Sattler et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Mapping and inventorying active rock glaciers in the northern Tien Shan of China using satellite SAR interferometry

et al. 2017

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Abstract. Rock glaciers are widespread in the Tien Shan. However, rock glaciers in the Chinese part of the Tien Shan have not been systematically investigated for more than 2 decades. In this study, we propose a new method that combines SAR interferometry and optical images from Google Earth to map active rock glaciers (ARGs) in the northern Tien Shan (NTS) of China. We compiled an inventory that includes 261 ARGs and quantitative information about their locations, geomorphic parameters, and downslope velocities. Our inventory shows that most of the ARGs are moraine-derived (69 %) and facing northeast (56 %). The altitude distribution of ARGs in the western NTS is significantly different from those located in the eastern part. The downslope velocities of the ARGs vary significantly in space, with a maximum of about 114 cm yr−1 and a mean of about 37 cm yr−1. Using the ARG locations as a proxy for the extent of alpine permafrost, our inventory suggests that the lowest altitudinal limit for the presence of permafrost in the NTS is about 2500–2800 m, a range determined by the lowest ARG in the entire inventory and by a statistics-based estimation. The successful application of the proposed method would facilitate effective and robust efforts to map rock glaciers over mountain ranges globally. This study provides an important dataset to improve mapping and modeling permafrost occurrence in vast western China.

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Section: General Statistics Of the Inventorysupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Mapping and inventorying active rock glaciers in the northern Tien Shan of China using satellite SAR interferometry

et al. 2017

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“…Despite general awareness on the limitations involved with drawing clear-cut boundaries between active, inactive and relict categories, this classification scheme is the most widely adopted in rock glacier studies (e.g. Imhof, 1996;Putnam and Putnam, 2009;Angillieri, 2010;Scapozza and Mari, 2010;Lilleøren and Etzelmüller, 2011;Scotti et al, 2013;Azócar, 2014;Bornet, 2014;Onaca et al, 2017).…”

Section: Degree Of Activity (Or Dynamic Classification)mentioning

confidence: 99%

Evaluating sources of uncertainty and variability in rock glacier inventories

Brardinoni

Scotti

Sailer

et al. 2019

Earth Surf Processes Landf

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This paper aims to evaluate sources of uncertainty and variability associated with rock glacier inventories compiled from remotely sensed imagery. To this end, we ran three mapping exercises in Kaiserbergtal, Austria. To evaluate interactions between mapping style and imagery resolution, we asked six operators to map and assess the degree of activity of all rock glaciers they could identify – first on Google Earth™ (GE) imagery and then on a set of higher‐resolution orthophotos and LiDAR‐derived images (LO) (Exercise 1). To compare the mapping attributes on a common set of rock glaciers, we asked 14 operators to delineate the outline of four designated rock glaciers (Exercise 2) and to classify the activity of 15 designated rock glaciers (Exercise 3) on LO. Results show strikingly high inter‐operator variability. Specifically, we show that the number of mapped rock glaciers on GE can vary up to a factor of 3, and that using LO lowers this figure to a factor of 2, while producing an increase in the number of mapped landforms, which become systematically smaller (Exercise 1). Examination of polygon outlines identifies highest inter‐operator variability at the transition with the rooting zone and, in polymorphic rock glaciers, on adjacent creeping lobes. Variability is higher for relict landforms (Exercise 2). Operators’ activity assessments, evaluated against an independent quantitative activity index (RGI), display reasonable agreement for active and relict landforms, whereas inactive counterparts meet least consensus and therefore are problematic (Exercise 3). We further show that this variability in mapping outcomes propagates across compound variables, and must be considered when assessing uncertainties and confidence levels of environmental evaluations that rely on rock glacier inventories, such as the lower altitudinal limit of discontinuous permafrost, or water storage potential. We call for an international effort to establish guidelines for rock glacier classification and mapping, towards more homogeneous inventories. © 2019 John Wiley & Sons, Ltd.

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“…into active, inactive, and relict types (Sattler et al, 2016). In general, the presence of ice within active and inactive rock glaciers is indicated by a steep (> 35 • ) frontal slope (Ikeda and Matsuoka, 2002), a well-developed flow-like morphology defined by sets of parallel and curved ridges separated by long v-shaped furrows (Barsch, 1996;Roer and Nyenhuis, 2007), and an absence or sparse occurrence of vegetation (Onaca et al, 2013). Inactive rock glaciers also contain ice but are immobile.…”

Section: Rock Glacier Inventory Classification and Databasementioning

confidence: 99%

Responses to L. Copland

Anonymous

2018

Preprint

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Rock glaciers are typical periglacial landforms. They can indicate the existence of permafrost, and can also shed light on the regional geomorphological and climatic conditions under which they may have developed. This article provides the first rock glacier inventory of Daxue Shan, south-eastern Tibetan Plateau. The inventory is based on analyses of Google Earth imagery. In total, 295 rock glaciers were identified in Daxue Shan, covering a total area of 55.70 km 2 between the altitudes of 4300 and 4600 m above sea level. Supported by ArcGIS and SPSS software programmes, we extracted and calculated morphometric parameters of these rock glaciers, and analysed the characteristics of their spatial distribution within Daxue Shan. Our inventory suggests that the lower altitudinal boundary for permafrost across the eight aspects of observed slopes differs significantly and that the lower altitudinal permafrost boundary is ∼ 104 m higher on western than eastern-facing slopes. Moraine-type and talus-derived rock glaciers exhibit mean gradients that are all concentrated within the 22-35 • range. However, lobate rock glaciers (27-45 • ) have a higher mean gradient than tongue-shaped rock glaciers (22-35 • ). Shady (i.e. N, NE, and E) slopes appear related to the presence of moraine-type rock glaciers, whereas sunny (i.e. W, SW, and S) slopes appear related to the presence of talus-derived rock glaciers. Rock glaciers in Daxue Shan are more concentrated within tertiary monzonitic granite, which is more sensitive than other lithological components to the freeze-thaw process. Continuous weathering of this substrate provides the ideal raw material for the rock glacier development. These results show that environmental controls (i.e. topographical, climatic, lithological factors) greatly affect the formation and development of rock glaciers. This study provides important data for exploring the relation between maritime periglacial environments and the development of rock glaciers on the south-eastern Tibetan Plateau (TP). It may also highlight the characteristics typical of rock glaciers found in a maritime setting.

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Southern Carpathian rock glaciers: Inventory, distribution and environmental controlling factors

Cited by 46 publications

References 54 publications

Mapping and inventorying active rock glaciers in the northern Tien Shan of China using satellite SAR interferometry

Mapping and inventorying active rock glaciers in the northern Tien Shan of China using satellite SAR interferometry

Evaluating sources of uncertainty and variability in rock glacier inventories

Responses to L. Copland

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