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首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Patterns of surface downwearing on shore platforms in eastern Canada
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Patterns of surface downwearing on shore platforms in eastern Canada

机译：加拿大东部海岸平台的表面磨损现象

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摘要

Downwearing rates were measured on shore platforms at about 200 transverse micro-erosion meter (TMEM) stations, over periods ranging from 2 to 6 years. There were seven study areas in eastern Canada. The platforms were surveyed and a Schmidt Rock Test Hammer was used to measure rock hardness. More than 1200 rock samples from three of the study areas were also subjected each day, over a 3 year period, to two tidal cycles of immersion and exposure, which simulated the central intertidal zone. A further 840 samples were subjected to longer periods of exposure and immersion, over a 1 year period, which represented different elevations within the upper and lower intertidal zone, respectively. These experiments suggested that tidally generated weathering and debris removal is an effective erosional mechanism, particularly at the elevation of the lowest high tides. In the field, mean rates of downwearing for each study area ranged from 0·24 mm yr~(-1) to more than 1·5 mm yr~(-1). Rates tended to increase with elevation in the field, with maxima in the upper intertidal zone. This trend in the field cannot be attributed entirely to the tidally induced weathering processes that were simulated in the laboratory, and must reflect, in part, the effect of waves, frost, ice, and other mechanisms. It is concluded that there are no strong spatial downwearing patterns on shore platforms, and that downwearing rates in the intertidal zone are the result of a number of erosional mechanisms with different elevation-efficacy characteristics. Furthermore, even if only one or two mechanisms were dominant in an area, any resulting relationship between downwearing rates and elevation would be obscured or eliminated by the effect of variations in the chemical and physical characteristics of the rocks.
机译：在2到6年的期间内，在约200个横向微腐蚀仪（TMEM）站的岸上平台上测量了磨损率。加拿大东部有七个研究区。对平台进行了调查，并使用Schmidt岩石测试锤来测量岩石硬度。在3年的时间里，每天还对来自三个研究区域的1200多个岩石样品进行了两次浸没和暴露的潮汐周期模拟了中间潮间带。在一年的时间内，又对840个样品进行了更长的暴露和浸泡时间，分别代表潮间带上部和下部的不同高度。这些实验表明，潮汐产生的风化和碎屑清除是一种有效的侵蚀机制，尤其是在最低潮汐高处。在该领域中，每个研究区域的平均穿着率在0·24 mm yr〜（-1）到1·5 mm yr〜（-1）以上。速率倾向于随田间海拔的升高而增加，最大值位于潮间带上部。该领域的趋势不能完全归因于在实验室中模拟的潮汐诱发的风化过程，并且必须部分反映波浪，霜冻，冰和其他机制的影响。可以得出结论，海岸平台上没有强烈的空间磨损现象，潮间带的磨损率是许多具有不同高程效用特征的侵蚀机制的结果。此外，即使一个区域中只有一种或两种机制占主导地位，磨损率和高程之间的任何由此产生的关系也将由于岩石的化学和物理特性变化的影响而被掩盖或消除。

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