7
11.89
7

Publication History View all

  • [Show abstract] [Hide abstract]
    ABSTRACT: No abstract
    International Journal of Nautical Archaeology 02/2007; 25(1):55 - 65.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Honeycomb weathering has been observed in a Carboniferous sandstone at a coastal location near Ballycastle on the north coast of Northern Ireland. Specimens of this sandstone have been analysed by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Results reveal that calcium sulphate (gypsum) is the only salt present and is found only at and immediately below the rock surface. SEM observations suggest that crystallization of salts in pores could easily dislodge quartz grains to promote granular disintegration, whilst etching of quartz grain surfaces attests to chemical weathering activity within the rock However, the reason for the development of the honeycomb pattern is not known.
    Earth Surface Processes and Landforms 07/2006; 10(5):509 - 518.
  • [Show abstract] [Hide abstract]
    ABSTRACT: A laboratory experiment has been conducted to examine the effects of ‘frost and salt’ weathering (i.e. physical breakdown by the freezing of salt solutions) on a limestone. Results show that the presence of certain salts in solution can inhibit frost damage. These findings are in direct conflict with those presented by Goudie (1974) and, more recently, Williams and Robinson (1981).Comparison of the experimental methods used in each of these three studies suggests that opposing results can be explained in terms of the different experimental procedures which were employed. If salt supply is frequent and plentiful then it seems likely that rock breakdown will be enhanced-this is the case represented by the experiment of Williams and Robinson. Conversely if the salt supply is limited and the amounts of salt remain more or less constant then rock breakdown will be inhibited-the case of the present experimental study. Caution is therefore advocated when attempting to extrapolate laboratory-derived results to infer on the behaviour of rocks under natural conditions.Several environmental situations in which ‘frost and salt’ weathering may be a possibility are dsiscussed, but it is concluded that further field data, especially concerning temperature regimes and salt availability at and below rock surfaces in cold regions, would be necessary before more definite statements could be made about the efficacy of this process.
    Earth Surface Processes and Landforms 07/2006; 7(5):475 - 488.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Geomorphologists have not devoted sufficient attention to the formation of clay minerals by hydrothermal activity. This paper describes the breakdown of freshly-quarried basalt by cyclic wetting and drying. Breakdown is attributed to the swelling of hydrothermally-derived smectite, and it is argued that the effects of endogenic processes can exert a significant control upon weathering behaviour under earth surface conditions.
    Earth Surface Processes and Landforms 07/2006; 7(2):189 - 195.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In the common orb-web spider Metellina segmentata, males are more powerfully built with longer legs, although females are heavier because of their egg load. Males guard females before attempting to mate, and there is considerable male–male competition because of the male-biased operational sex ratio. We used a field removal experiment to examine (1) seasonal changes in the average morphology of guarding males and (2) whether there is a pool of small males that is excluded from the webs of females. Morphological measures were subjected to a principal components analysis and changes in PC scores were examined for seasonal effects and the effects of previous removal of males. The size of guarding males (PC1) increased over the season, suggesting that smaller males were increasingly excluded from webs, but the condition of guarding males (PC2) decreased, indicating that energy reserves are depleted because the males gain little access to food during the reproductive season. When guarding males were removed, smaller males were able to take up residence. Our results show that large males have a clear advantage in monopolizing females. We discuss the manner in which selection acts to maintain large male size in this spider.Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
    Animal Behaviour. 06/2003;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Tephra-dated palynological investigations of lowland peats which have accumulated over the last millennium, provide an excellent means of tracing recent landscape change. Pollen analytical investigations of lowland raised bogs in the northern and western counties of the province show past regional variations. At one extreme northern lowland site, the landscape has remained relatively unchanged over much of the last millennium, while in the western county agricultural expansion linked to the rise of the great estates in the 18th century is observed. These findings provide those concerned with conservation and landscape restoration with information on which to base woodland planting.
    Review of Palaeobotany and Palynology 01/1998;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Four rock types (basalt, sandstone, granite, and chalk) are examined with respect to the maximum surface temperatures which they experience when subjected to similar conditions of exposure. Rock temperature measurements are reported for an urban environment and for two experimental situations in which an infrared lamp is used to simulate heating under cold and hot conditions. Differences in rock temperatures are discussed with reference to thermal rock properties (albedo, specific heat capacity, and thermal conductivity). Some natural situations are suggested in which thermal rock properties could conceivably play a role in determining the extent to which rocks would be affected by particular weathering processes.
    Earth Surface Processes and Landforms 02/1985; 10(2):125 - 136.
Information provided on this web page is aggregated encyclopedic and bibliographical information relating to the named institution. Information provided is not approved by the institution itself. The institution’s logo (and/or other graphical identification, such as a coat of arms) is used only to identify the institution in a nominal way. Under certain jurisdictions it may be property of the institution.