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The origin of calcium carbonate nodules forming on Flathead Lake delta, northwestern Montana
Author(s) -
Moore Johnnie N.
Publication year - 1983
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.1983.28.4.0646
Subject(s) - flathead , carbonate , calcareous , calcium carbonate , delta , productivity , geology , oceanography , geochemistry , environmental science , hydrology (agriculture) , chemistry , paleontology , biology , fishery , fish <actinopterygii> , organic chemistry , aerospace engineering , engineering , geotechnical engineering , macroeconomics , economics
The subaqueous levees of Flathead Lake delta, Montana, are covered with calcareous nodules and crusts. Such deposits are unexpected in such large oligotrophic lakes with low ionic concentrations. Algal photosynthesis and metabolism concentrate calcium carbonate and silica where nutrients are continually supplied from the Flathead River. As the nodules accrete, carbonate and silica are dissolved and reprecipitated, forming a complex internal zonation. The nodules form only when high water levels correspond to seasonal peaks in productivity. Such a situation is a recent phenomenon occurring only since 1938 when Kerr Dam was built to control lake levels for the purpose of power generation.