Rock surface micro−roughness, Schmidt hammer rebound and weathering rind thickness within LIA Skálafellsjökull foreland, SE Iceland

Abstract

Glacially abraded basaltic rock surfaces found within a Little Ice Age (LIA) fore− land of Skálafellsjökull (SE Iceland) were studied at eight sites of different age applying different weathering indices. They include surface micro−roughness parameters measured with the Handysurf E35−B electronic profilometer -a new tool in geomorphology, Schmidt hammer rebound (R−values) and weathering rind thickness. Values of these indices ob− tained from study sites exposed to subaerial weathering for more than ca. 80 years are sig− nificantly different than those from younger moraines closer to the glacier snout. Despite a wide scatter of readings within each study site, there is a significant correlation between the ages and the values of the indices. It is concluded that the micro−roughness parameters pro− vided by the Handysurf E35−B profilometer, Schmidt hammer R−values and weathering rind thickness are robust indices of rock surface deterioration rate in short time−scales. There is mounting evidence that rock surface undergoes relatively rapid weathering during first decades since deglaciation.

Application of the Handysurf E-35B electronic profilometer for the study of weathering micro-relief in glacier forelands in SE Iceland

“…This correlation is in accordance with abundant previous research focusing on the Schmidt hammer or weathering rinds developed on deglaciated terrains in millennial time-scales (Carroll 1974;Porter 1975;Chinn 1981;Matthew and Shakesby 1984;McCarroll 1989McCarroll , 1991Nesje 1993, 1996;Aa and Sjåstad 2000;Kotarba et al 2002;Winkler 2005;Shakesby et al 2006;Owen et al 2007;Nicholson 2009;Matthew and Owen 2011), as well as with rather limited studies performed within LIA forelands (Evant et al1999;Etienne 2002;Matthews and Owen 2008;Dąbski 2009Dąbski , 2012Dąbski , 2014Dąbski and Tittenbrun 2013).…”

“…The study is a continuation and further elaboration of previous research performed by Dąbski (2012Dąbski ( , 2014 and Dąbski and Tittenbrun (2013) who worked on the forelands of Fláajökull and Skálafellsjökull (Iceland) and the Biferten Glacier (Switzerland). In this paper, the study was broadened to include the Icelandic marginal zones of Hoffellsjökull and Virkisjökull and the results were further evaluated.…”

“…4E) are expressed in micrometres and include: Ra -integral value of the roughness profile (mean deviation from the centre line); Rz -average amplitude of roughness profile (average vertical distance between peaks and lows); Rzmax -maximum height of irregularities; Rsm -average wave length or horizontal distance between peaks or lows (Handysurf E-35B Instruction Manual). Former studies of Dąbski (2012Dąbski ( , 2014 and Dąbski and Tittenbrun (2013) proved that values of Rz are closely mirrored by Rzmax, therefore only Rz is considered in this article as more objective, because it shows the average amplitude of a micro-relief, not the maximum.…”

“…They used a micro-meter and a profile gauge, capable of measuring a micro-relief amplitude of a few millimetres and detected significant differences in rock surface roughness between landforms created in the Little Ice Age (LIA) and those from the onset of the Holocene. However, it was recently shown by Dąbski (2012Dąbski ( , 2014 and Dąbski and Tittenbrun (2013), that even much shorter, decadal time-scales allow for the differentiation of rock surface roughness (later addressed as Application of the Handysurf E-35B electronic profilometer for the study of weathering micro-relief in glacier forelands in SE Iceland micro-roughness), resulting from paraglacial subaerial weathering of basalts in Iceland.…”

Lichenometry and Schmidt hammer tests in the Kaunertal glacier foreland (Ötztal Alps) during the AMADEE-15 Mars Mission Simulation

“…The contemporary shrinkage of the cryosphere is resulting in the recession of glaciers and the melting of permafrost on a global scale (Huber et al 2005), but has also led to a collaborative international effort to gather information on the contemporary behaviour of glaciers and rock glaciers (WGMS 2016;GAPHAZ 2017). This is accompanied by developments and discussions on dating (Hubbard & Glasser 2005), among which lichenometry and Schmidt hammer are very popular, but there are still different approaches to these methods (Winkler & Shakesby 1995;Evans et al 1999;Bradwell 2009;Dąbski 2007Dąbski , 2009Dąbski , 2014, which justifies our research in Kaunertal.…”