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Two‐hourly surface change on supra‐tidal rock (Marengo, Victoria, Australia)
Author(s) -
GómezPujol Lluís,
Stephenson Wayne J.,
Fornós Joan J.
Publication year - 2007
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.1373
Subject(s) - morning , cliff , relative humidity , evening , geology , hydrology (agriculture) , insolation , environmental science , atmospheric sciences , climatology , meteorology , geotechnical engineering , geography , paleontology , medicine , physics , astronomy
A traversing micro‐erosion meter was used to measure rock surface micro‐topography over 40 cm 2 on a supra‐tidal cliff face from early morning to late evening in late spring. From 06:00 hours to 22:00 hours the relative heights of 188 coordinates were obtained using the meter at 2‐hour intervals, resulting in a data set of 1607 readings. Monitoring shows that rock surfaces are dynamic entities, with significant rise and fall relative to the first measurement at shorter timescales than previously reported. The maximum positive rise between readings was 0·261 mm and lowering was 0·126 mm. The pattern of change did not relate as expected to environmental variables such as temperature or insolation. Rather, the surface showed greater surface change in the early morning and late afternoon. It is hypothesized that this pattern relates to the expansion and contraction of lichen thalli as moisture is absorbed during higher humidity in the morning and late afternoon. The implications of these results for weathering studies are considered. Copyright © 2006 John Wiley & Sons, Ltd.