the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Characterizing ground ice content and origin to better understand the seasonal surface dynamics of the Gruben rock glacier and the adjacent Gruben debris-covered glacier (southern Swiss Alps)
Abstract. Over the recent years, there has been focused international efforts to coordinate the development and compilation of rock glacier inventories. Nevertheless, in some contexts, identifying and characterizing rock glaciers can be challenging as complex conditions and interactions, such as glacier-rock glacier interactions, can yield landforms or landform assemblages that are beyond a straightforward interpretation and classification through ordinary visual means alone. To gain a better understanding of the spatial and temporal complexity of the ongoing processes where glacier-permafrost interactions have occurred, the characterization of the subsurface of the Gruben rock glacier and its adjacent complex contact zone is quantitively assessed using a petrophysical joint inversion (PJI) scheme, based on electrical resistivity (ERT) and refraction seismic (RST) data. Surface dynamics are assessed using both in-situ and close-range remote sensing techniques to monitor daily and seasonal displacements and to monitor landform-wide surface changes at high spatial resolution, respectively. Both the geophysical and geodetic surveys allowed to identify two zones: the rock glacier zone and the complex contact zone where both permafrost and embedded surface ice are present. In the complex contact zone extremely high ice contents (estimated up to 85 %) were found. Widespread supersaturated permafrost conditions were found in the rock glacier zone. Surface displacement rates in this zone are typical of permafrost creep behaviour, with a gradual acceleration in late spring and a gradual deceleration in winter. Moreover, the coherent nature of the rock glacier zone surface deformation contrasts with the back-creeping and slightly chaotic surface deformation of the complex contact zone. Favouring a multi-method approach allowed a detailed representation of the spatial distribution of ground ice content and origin, which enabled to discriminate glacial from periglacial processes as their spatio-temporal patterns of surface change and geophysical signatures are (mostly) different.
- Preprint
(6102 KB) - Metadata XML
- BibTeX
- EndNote
Status: final response (author comments only)
-
RC1: 'Comment on egusphere-2024-1283', Adriano Ribolini, 05 Aug 2024
I read with attention and interest the paper by Julkie Wee et al "Characterizing ground ice content..." I found the paper interesting, well written and illustrated, and I see no obstacles to its publication.
The Gruben rock glacier / debris-covered glacier is a key site for understanding the permafrost/glacier relationships, and there are numerous papers on various aspects (thermal behavior, geomorphological characteristics, geophysics, etc).
The merit of this paper is not that of having used the individual investigations (which are not innovative from a methodological point of view), but of having used a Petrophysical Joint Inversion in this well-known site, which has been at the centre of many scientific discussions. The built dataset consists of a potential distribution of ice, water, rock phases, eventually associated with thermal and surface dynamics data. What derives from this exercise is an integrated synthesis that supports a robust and adequately quantitative interpretation, as is necessary when we want to disentangle complex mechanical processes (glacial sediments transport/deformation, permafrost creep of frozen material) that lead to landforms that are not always clearly distinguishable.
The methods are illustrated with the necessary summary, the data are well illustrated and their interpretation clearly exposed.
In some points in the text reference is made to the contribution of geomorphological knowledge in integrating the interpretation of the data, or even some choices in the model. I understand that this is not the purpose of the paper, but I suggest adding (even in parentheses) some information about it.
In the comparison between the results of the conventional RST and ERT inversions and the PJI-derived ones, the differences relating to seismic velocities are highlighted. I suggest discussing whether those relating to resistivity are irrelevant or could have a weight in terms of data interpretation (especially the minimum resistivity values).
I added a few minor annotations to the paper’s PDF file.
Hope this helps
Best wishes
Adriano Ribolini
-
RC2: 'Comment on egusphere-2024-1283', Anonymous Referee #2, 10 Sep 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-1283/egusphere-2024-1283-RC2-supplement.pdf
Viewed
HTML | XML | Total | BibTeX | EndNote | |
---|---|---|---|---|---|
370 | 181 | 75 | 626 | 31 | 31 |
- HTML: 370
- PDF: 181
- XML: 75
- Total: 626
- BibTeX: 31
- EndNote: 31
Viewed (geographical distribution)
Country | # | Views | % |
---|
Total: | 0 |
HTML: | 0 |
PDF: | 0 |
XML: | 0 |
- 1