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RECORDING DENSITOMETRY OF X‐RADIOGRAPHS FOR THE STUDY OF CRYPTIC LAMINATIONS IN THE SEDIMENT OF LAKE WASHINGTON
Author(s) -
EDMONDSON W. T.,
ALLISON DAVID E.
Publication year - 1970
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1970.15.1.0138
Subject(s) - densitometer , densitometry , sediment , deposition (geology) , geology , mineralogy , geomorphology , optics , physics
X‐radiographs of cores of sediment from Lake Washington reveal prominent laminations not visible to the eye. Measurement of the film density with a recording densitometer provides an exact and objective record of these laminations. The strongest band, at a depth of about 16 cm in the central part of the lake, is attributed to the lowering of the lake level in 1916. The mean rate of deposition therefore has been about 3.1 mm/yr. The most prominent bands more recent than 1916 are too few to be annual, but the fine structure of these bands shown by the densitometer record may result from annual variations in deposition. The film density is strongly correlated with the dry weight and mineral residue of the sediment.