Ten types of sedimentary rock were subjected to repeated cycles of freezing and thawing. In addition to monitoring sample weight loss throughout testing, a detailed graphic record was made of deterioration mode and its relationship to pre-existing rock flaws. Results suggest that the presence or absence of rock flaws alone does not control deterioration mode, but rather that it is the coupled relationship between these flaws, and rock strength and textural properties which exerts greatest influence.While some pre-existing flaws such as syndepositional deformation structures do not appear to influence breakdown, others such as incipient fractures, cavities and minor lithological boundaries frequently coincide with concentrations of deterioration. A characteristic mode of deterioration which is independent of pre-existing flaws tends to develop in sandstones, indicating the influence, in this case, of rock texture. Particularly strong rocks such as crystalline limestone and metasediment tend to fracture preferentially along distinct linear weaknesses such as mineral veins, stylolites and incipient fractures. Particularly weak rocks, such as low-density chalk, break down in a random fashion without regard to pre-existing flaws.In addition to providing some insight into the role of pre-existing flaws in rock deterioration, this work also has practical implications for (i) the study of landform development due to weathering, and (ii) the selection of representative rock samples in durability testing for building stone.

The results are reported of four experimental weathering tests -freeze -thaw, wetting and drying, slake durability and salt weathering -on five different types of limestone. Effective porosity, mercury intrusion porosimetry and scanning electron microscopy were used to evaluate changes in pore properties, while weight loss and fracture density were used to assess deterioration severity. A primary aim was to observe modifications in porosity due to weathering and to draw inferences about the internal rock deterioration mechanisms taking place.It is concluded that the five limestones not only show a wide range of resistance to weathering in general but considerable difference in resistance to particular weathering processes. Consequently, when assessing durability it is essential to consider rock properties in the context of the weathering process to which the rock is subject. The type of deterioration indicator used is also important in interpretation of durability.A variety of pore modification mechanisms operate, including changes in pore connectivity, pore infilling, and the introduction of additional void space. There are indications that changes to the internal pore structure of rocks due to weathering may be a precursor to more substantial macrodeterioration.

Post-glacial weathering of ice-eroded metamorphic bedrock was investigated in the Røldal area (608N) of the Hardangervidda Plateau in southern Norway. Quartz veins were used as reference surfaces to determine a mean post-glacial surface lowering rate of 0.55 mm ka 21 . Chemical characteristics of late-season runoff were determined for one catchment (Snøskar) and a chemical erosion rate of 4.9 t km 22 a 21 was obtained. A mean in situ fracture enlargement due to microweathering of 0.12 mm ka 21 was also determined. These rates are low, although comparable with similar environments in cold regions, and suggest that microweathering has had relatively little impact on Holocene landscape evolution. Weathering rind thickness was found to be less on fracture walls than on exposed bedrock surfaces, suggesting fractures have not played a significant role in microweathering. Observations of weathering morphology reveal a range of forms including shallow spalling, tafoni and pseudokarren, indicating locally intense weathering activity. Analysis of interrelationships between multiple weathering indices points to the importance of bedrock microweathering as a precursor to macro-breakdown and landform evolution. The research reasserts the importance of chemical activity in cold environments and the importance of moisture supply for effective microweathering.

Partnership is currently the focus of much work within higher education and advocated as an important process to address a range of higher education goals. In this paper, we propose the term inclusive partnership to conceptualise a non-selective staff?student relationship. While recognising the challenges of inclusive partnership working for institutions, staff and students, this paper outlines the opportunities it offers and provides detailed case studies of inclusive partnerships within the geography curriculum. We conclude with some guiding principles to inform the development of inclusive partnerships in a range of settings.Peer reviewe

Microweathering of ice-smoothed bedrock surfaces was investigated in the Røldal area of Hardanger Plateau (60°), southern Norway. Postglacial rates of weathering were determined from surface lowering using quartz veins as reference surfaces. Weathering processes are inferred from assessment of weathering rind formation, surface hardness, and the preservation of small-scale glacial erosional features. Surface lowering rates for a range of metamorphic rocks vary from 0.05 to 2.20 mm ka − 1 and are broadly comparable with those obtained from crystalline rocks in other periglacial environments. The mean rate of surface lowering at 0.55 mm ka − 1 is low and demonstrates the relatively small impact of microweathering on postglacial landscape evolution. Variations in bedrock microweathering can be explained by lithological variation. Amphibolite and mica-rich bedrock surfaces experience greater denudation and weakening, least weathering rind formation, and abundant preservation of glacial striae, despite greater surface lowering. Conversely, quartz-rich bedrock surfaces are most resistant to denudation and weakening, but have greater weathering rind formation and fewer preserved striae. Postglacial microweathering is achieved primarily through granular disintegration involving detachment and removal of mineral grains and weakening from increased porosity. Granular decomposition is manifest in the formation of weathering rinds. Analysis of interactions between weathering indices indicates that rind accumulation is limited by microerosion. A conceptual model is proposed that illustrates the temporal interrelationships between in situ and erosional facets of microweathering in two contrasting mineral assemblages. The model proposes that cyclic processes of in situ disintegration, decomposition, and erosion are at work. The relative balance between these processes varies with lithology so that in more resistant quartz-rich rocks the net effect is minimal surface lowering and accumulation of weathering rind. In weaker, amphibolitic and micaceous rocks, the net effect is greater surface lowering and minimal accumulation of weathering rind. The results of the research demonstrate the important influence of rock properties, notably mineral composition, in postglacial microweathering of crystalline bedrock in a periglacial environment.