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Weathering Assessment of Quartz Grains: A Semiquantitative Approach
Author(s) -
Darmody R. G.
Publication year - 1985
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1985.03615995004900050050x
Subject(s) - weathering , quartz , mineralogy , grain size , scanning electron microscope , geology , texture (cosmology) , feature (linguistics) , materials science , composite material , geomorphology , artificial intelligence , image (mathematics) , computer science , linguistics , philosophy
This paper details the development of a technique to assess the relative weathering state of quartz grains as revealed by scanning electron microscopy (SEM). This approach considers the criticisms leveled against environmental assessments based on SEM observations. The method uses only one size fraction of grains to eliminate size dependent surface texture variability. Operator bias is removed by coding specimens. A semiquantitative approach is used: five grain surface features indicative of “weathering” and five indicative of “freshness” are observed on each grain. A binary scoring system is used where a negative point is assigned for the presence of a weathering feature and a positive point is assigned for the presence of a freshness feature. A zero is assigned for each absent indicator feature. Summing the points gives the weathering class (WC) for a grain. The mean WC for 15 to 30 grains is the weathering classification for a sample. This systematic approach is an improvement over qualitative assessments and allows for statistical analysis of the data.