Wetting and drying is an acknowledged yet still poorly understood rock weathering process. Previous experiments documented in the literature measure physical changes or mass loss in relation to moisture oscillations but only one study directly compares different moisture amplitudes by using different modes of moisture application. In this experimental study, four sets of sandstone tablets are subjected to 48 h wetting and drying cycles at set moisture content fluctuations of 29, 42, 56 and 63% respectively. A common moisture application, full immersion, is used for all four sets. Mass loss after 52 cycles averaged 0·27%, some three times more than that of the control samples. Average porosity of the samples increased, while water absorption capacities and the saturation coefficients of the samples decreased. No discernable difference in mass loss or change in physical properties was found between the different sample sets. When compared with previous studies, results suggest that the effect of moisture application type may be more of a controlling factor on the weathering effect than actual moisture content achieved. A need to move towards a more standardized approach in wetting and drying experimental studies is emphasized.

Downslope extension of pronival (protalus) ramparts has been proposed to occur at the foot of thickening snowbeds or firn fields. A suggested morphological characteristic of such landforms is that the distal slope is formed at repose (34-38°) by the accumulation of cohesionless cascading debris. However, data on rampart morphology and debris accumulation, in terms of locality of deposition, of an actively-forming pronival rampart at Grunehogna Peaks, Western Dronning Maud Land, Antarctica demonstrates that, although rockfall debris accumulation indicates downslope (outward) rampart extension, this landform does not possess a distal slope at repose. In addition, observations from the austral summers of 2006/7 and 2008/9 suggest that the firn field size is stable. The aim of this paper is to demonstrate that the morphological characteristics and environmental conditions under which pronival ramparts develop according to the model of downslope extension may be more varied than originally thought. Moreover, this paper questions the use of the morphology of fossil features to infer rampart formation and highlights that caution should be used when using pronival ramparts in palaeo-environmental reconstructions.

Accurate citation practices are important, from both an ethical and a scientific point of view. Using an easily reproducible, previously published method, we assess citation accuracy in 120 articles published in the first half of 2011 and listed under ‘Physical Geography’ in Thomson Reuters’ ISI Web of Knowledge Science Citation Index. Our results indicate that at least 19% of citations in physical geography do not provide clear support for the statements they are meant to support. These results are in line with previously published findings for ‘field-orientated’ sciences. We propose that both authors and editors help remedy this problem, by employing more rigorous writing and editing practices.

Investigations of openwork block deposits have the potential to improve understanding of the production of substrates for biological colonisation, the control of geological structure and the impacts of climate change on landforms. As part of research into the morphology and characterisation of a blockfield located on the Northern Buttress of the Vesleskarvet Nunataks, Western Dronning Maud Land, Antarctica (2°W, 71°S), this paper investigates the influence that aspect has on weathering for a blockfield using data collected during the 2009–2012 Austral summer seasons. Proxy data recorded for weathering included rock hardness rebound values as well as visual evidence of flaking, pitting, surface roughness and lichen presence. Aspect was found to affect weathering of blockfield samples across the study site, with the south‐facing sides being the least weathered of the directional aspects. This paper argues that a higher radiation budget associated with slope aspect and angle could drive thermal regimes and subsequent weathering of clast faces. Furthermore, in the absence of abundant precipitation, ice and snow cover become the primary source of moisture in this high‐latitude Antarctic environment.

Loubser, M.J., 2013. Wetting and drying weathering of basalt and sandstone: A process isolation study.ABSTRACT. Rock samples from Marion Island in the SubAntarctic and from the Drakensberg, South Africa were divided into sets and subjected to wetting and drying at two different moisture amplitudes to determine changes in physical rock properties. The rock samples were subjected to a total of 105 wetting and drying cycles. Rock porosity and water absorption capacity was determined both at the beginning and at the end of the experiment and compared. Results varied from set to set, but not as a result of variations in moisture amplitude. Three key findings are presented. First, it seems that the number of wetting and drying cycles is a more important factor than the degree to which the samples have been saturated. Second, changes in rock properties were detected for the control samples as well as the field samples, suggesting that the experimental techniques used for determining the rock properties have themselves affected the samples. Third, samples that outwardly appeared very similar have responded differently to wetting and drying. This implies that even small changes in internal rock structure can have a profound effect on the ultimate nature of the weathering taking place.