The weathering of granitic rocks in a hyper-arid and hypothermal environment: A case study from the Sør-Rondane Mountains, East Antarctica

Kanamaru, Tatsuo; Suganuma, Yûsuke; Oiwane, Hisashi; Matsui, Hideki; Miura, Makoto; Okuno, Jun’ichi; Hayakawa, Hitoshi

doi:10.1016/j.geomorph.2018.05.015

Cited by 22 publications

(9 citation statements)

References 31 publications

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“…This discussion section links results presented in Figures 1-13 to prior scholarship on cold climate rock-surface processes. The results clearly confirm findings by Rapp [23], Hall [14,[24][25][26], Dixon [27][28][29][30][31][32][33][34][35], Thorn [36][37][38], their collaborators, and others [40][41][42][43][44][45][46][47][105][106][107] on the importance of chemical processes in cold climate geomorphic settings. However, Figures 1-13 also reveal new details of rock-surface chemical l processes at the nanoscale that, we hope, opens the eyes of cold-climate researchers who only perceive "minimal chemical weathering" [39] when they see bare rock (e.g., Figures 1, 11 and 13a).…”

Section: Discussionsupporting

confidence: 84%

“…Unfortunately, there still exists the assumption by some of "minimal chemical weathering" in cold climates like Antarctica [39]. However, most scholars no longer consider biochemical and chemical rock decay processes as unimportant or even a distant second to physical rock decay, as evidenced by recent research [40][41][42][43][44][45][46][47] and Ph.D. dissertations [48] on cold-climate rock decay not having fight against those prejudiced by the old paradigm.…”

Section: Introductionmentioning

confidence: 99%

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Nanoscale Observations Support the Importance of Chemical Processes in Rock Decay and Rock Coating Development in Cold Climates

Dorn

Krinsley

2019

Geosciences

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Conventional scholarship long held that rock fracturing from physical processes dominates over chemical rock decay processes in cold climates. The paradigm of the supremacy of cold-climate shattering was questioned by Rapp’s discovery (1960) that the flux of dissolved solids leaving a Kärkevagge, Swedish Lapland, watershed exceeded physical denudation processes. Many others since have gone on to document the importance of chemical rock decay in all cold climate landscapes, using a wide variety of analytical approaches. This burgeoning scholarship, however, has only generated a few nanoscale studies. Thus, this paper’s purpose rests in an exploration of the potential for nanoscale research to better understand chemical processes operating on rock surfaces in cold climates. Samples from several Antarctica locations, Greenland, the Tibetan Plateau, and high altitude tropical and mid-latitude mountains all illustrate ubiquitous evidence of chemical decay at the nanoscale, even though the surficial appearance of each landscape is dominated by “bare fresh rock.” With the growing abundance of focused ion beam (FIB) instruments facilitating sample preparation, the hope is that that future rock decay researchers studying cold climates will add nanoscale microscopy to their bag of tools.

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Section: Discussionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Nanoscale Observations Support the Importance of Chemical Processes in Rock Decay and Rock Coating Development in Cold Climates

Dorn

Krinsley

2019

Geosciences

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“…Pour et al, 2019) and weathering indices (e.g. Kanamaru et al, 2018). Future work in this direction would improve the accuracy with which we are able to classify sediment covers, however, for now ground validation is still a crucial requirement to accurately differentiate a glacial deposit from in-situ weathered bedrock.…”

Section: Discussionmentioning

confidence: 99%

The glacial geomorphology of western Dronning Maud Land, Antarctica

et al. 2020

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Reconstructing the response of present-day ice sheets to past global climate change is important for constraining and refining the numerical models which forecast future contributions of these ice sheets to sea-level change. Mapping landforms is an essential step in reconstructing glacial histories. Here we present a new map of glacial landforms and deposits on nunataks in western Dronning Maud Land, Antarctica. Nunataks are mountains or ridges that currently protrude through the ice sheet and may provide evidence that they have been wholly or partly covered by ice, thus indicating a formerly more extensive (thicker) ice sheet. The map was produced through a combination of mapping from Worldview satellite imagery and ground validation. The sub-metre spatial resolution of the satellite imagery enabled mapping with unprecedented detail. Ten landform categories have been mapped, and the landform distributions provide evidence constraining spatial patterns of a previously thicker ice sheet.

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“…Selection of the sampled rock surfaces for each site was based upon photographs and field observation (Gallach et al, 2018). In the MBM, the colour of the granite surface (redness observed in other cold environments, e.g., Kanamaru et al, 2018), is not due to differences in rock elemental composition (Böhlert et al, 2008) but the occurrence of iron hydroxides that reflects weathering (Gallach et al, submitted). For this third campaign, high‐resolution photographs were processed with Adobe © Photoshop in order to highlight rock‐surface colour differences.…”

Section: Methodsmentioning

confidence: 99%

Climatic and structural controls on Late‐glacial and Holocene rockfall occurrence in high‐elevated rock walls of the Mont Blanc massif (Western Alps)

Carcaillet

Ravanel

Deline

et al. 2020

Earth Surf Processes Landf

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In the Mont Blanc massif (European Western Alps), rockfalls are one of the main natural hazards for alpinists and infrastructure. Rockfall activity after the Little Ice Age is well documented. An increase in frequency during the last three decades is related to permafrost degradation caused by rising air temperatures. In order to understand whether climate exerts a long-term control on rockfall occurrence, a selection of paleo-rockfall scars was dated in the Glacier du Géant basin [>3200m above sea level (a.s.l.)] using terrestrial cosmogenic nuclides. Rockfall occurrence was compared to different climatic and glacial proxies. This study presents 55 new samples (including replicates) and 25 previously-published ages from nine sampling sites. In total, 62 dated rockfall events display ages ranging from 0.03 ± 0.02ka to 88.40 ± 7.60ka. Holocene ages and their uncertainties were used to perform a Kernel density function into a continuous dataset displaying rockfall probability per 100years. Results highlight four Holocene periods of enhanced rockfall occurrence: (i) c. 7-5.7ka, related to the Holocene Warm Periods; (ii) c. 4.5-4ka, related to the Sub-boreal Warm Period; (iii) c. 2.3-1.6ka, related to the Roman Warm Period; and (iv) c. 0.9-0.3ka, related to the Medieval Warm Period and beginning of the Little Ice Age. Laser and photogrammetric three-dimensional (3D) models of the rock walls were produced to reconstruct the detached volumes from the best-preserved rockfall scars (≤0.91 ± 0.12ka). A structural study was carried out at the scale of the Glacier du Géant basin using aerial photographs, and at the scale of four selected rock walls using the 3D models. Two main vertical and one horizontal fracture sets were identified. They correspond respectively to alpine shear zones and veins opened-up during long-term exhumation of the Mont Blanc massif. Our study confirms that climate primarily controls rockfall occurrence, and that structural settings, coincident at both the massif and the rock wall scales, control the rock-wall shapes as well as the geometry and volume of the rockfall events.

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The weathering of granitic rocks in a hyper-arid and hypothermal environment: A case study from the Sør-Rondane Mountains, East Antarctica

Cited by 22 publications

References 31 publications

Nanoscale Observations Support the Importance of Chemical Processes in Rock Decay and Rock Coating Development in Cold Climates

Nanoscale Observations Support the Importance of Chemical Processes in Rock Decay and Rock Coating Development in Cold Climates

The glacial geomorphology of western Dronning Maud Land, Antarctica

Climatic and structural controls on Late‐glacial and Holocene rockfall occurrence in high‐elevated rock walls of the Mont Blanc massif (Western Alps)

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