The relationship between crack orientation and solar insolation in Wadi Shehah, Northern United Arab Emirates

Elisabeth Rewcastle
Department of Geography, Oxford Brookes University
August 2008

Abstract

In a recent study by McFadden et. al. (2005), it was proposed that; the north-south near vertical orientations of many rock surface cracks, relate to thermal stresses that arise daily from non-uniform solar heating, and that this mechanism is viable in other climates. This is based on clast and crack orientation data from eight sites in the deserts of North America. In this study, the presence of north to south cracking, potentially related to thermal stresses is confirmed at the study site in Wadi Shehah, the United Arab Emirates (UAE). However the proposed mechanism did not account for the majority of crack orientations, and a significantly smaller percentage of cracks with north-south orientations were recorded at the site in Wadi Shehah compared to the North American sites. This suggests that the mechanism is ‘viable’ in the UAE, but both less important, and less dominant as a process of rock breakdown than in the higher latitude North American deserts. Dominance of bi-modal and multi-modal crack orientations emphasize the significance of other processes and mechanisms in the initiation of cracking at this site, as well as solar insolation.

Keywords

physical weathering, diurnal variation, thermal stresses, meridional cracking, clast disintegration, Wadi Shehah

The relationship between crack orientation and solar insolation in Wadi Shehah, Northern United Arab Emirates by Elisabeth Rewcastle is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.

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Based on a work at geoverse.brookes.ac.uk.

Original Papers - Geoverse
ISSN 1758-3411
Editor-in-Chief: Professor Helen Walkington

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