Holocene lake sediments of Minnesota are represented by six facies: I)
northeastern-allogenic littoral sand and gravel, and profundal clay and copropel,
in Precambrian crystalline rocks, with low to high total carbohydrates, high and
variable amino acids, low to moderate hydrocarbons, and low to high pigments; II)
northwestern-mixed allogenic clastics, and authigenic copropel and marl, in
calcareous glacial drift and Pleistocene lake beds, with moderate carbohydrates, low
amino acids, and stratigraphically variable pigments; III) north-central-authigenic
marl, copropel, and allogenic sediments in thick calcareous glacial drift, with
moderate carbohydrates, low amino acids, and stratigraphically variable pigments;
N) east-central-authigenic copropel, marl, and allogenic clastics in calcareous and
noncalcareous glacial drift, with high carbohydrates and amino acids, high
hydrocarbons and polar lipids, high pigments, all stratigraphically variable; V)
west-central and southwestern-allogenic silt, marl, and sapropel in calcareous
glacial drift and gypsiferous Cretaceous shale, with high carbohydrates and amino
acids, stratigraphically variable, high aromatic hydrocarbons; and VI)
southeastern-allogenic fine clastics and copropel in Paleozoic clastic and carbonate
rock and pre-Wisconsin drift, with known organic residues similar to those in
Swain, F.M., 1992, Bottom Sediments and Organic Geochemical Residues of Some Minnesota Lakes, Minnesota: Minnesota Geological Survey Report of Investigations 41, 65 p.
RI-41 Bottom Sediments and Organic Geochemical Residues of Some Minnesota Lakes.
Minnesota Geological Survey.
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