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Rates and patterns of bedrock denudation by coastal salt spray weathering: A seven‐year record
Author(s) -
Mottershead D. N.
Publication year - 1989
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.3290140504
Subject(s) - denudation , bedrock , weathering , geology , halite , spatial variability , geomorphology , hydrology (agriculture) , physical geography , geotechnical engineering , paleontology , statistics , mathematics , structural basin , geography , tectonics
Abstract Rapid surface lowering of bedrock is taking place in the supratidal zone by salt spray weathering. A seven‐year run of data demonstrates a mean rate of lowering of 0·625 mm a −1 . Considerable variation exists in annual point lowering values within measurement sites, although between‐site variation is not significant. Aggregate year to year variations in surface lowering are not significant. Spatial variation in individual point values may be compensated by temporal variation over an 11‐year period. There is a marked summer maximum in surface lowering rate, and this is strongly correlated with monthly air temperature. Spatially and temporally episodic swelling of the rock surface is demonstrated. This does not correlate statistically with any available climatic variable and is deemed to be a real and largely stochastic phenomenon. It is interpreted as rock bursting at the granular scale due to haloclasty. The processes most likely to be responsible for the observed rapid denudation are crystallization and thermal expansion of halite, both of which are enhanced by high summer temperatures.