Organic depositions - Gyttja

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Gyttja

last modified by TerraIndex TerraIndex

on 2021/05/14 16:08

Table of Contents

Gyttja is a type of soil formed in nutrient rich water under aerobic conditions. Gyttja is made up from decomposed plants and animals. It is defined as fine-textured, plastic, often gelatinous material when wet but becomes hard when dry, as the material shrinks and cracks along horizontal planes. In thin sections, the organic materials in gyttja are yellow. Gyttja can contain traces of calcium carbonate. Gyttja deposits can be found in floodplains, fans and deltas of rivers and streams.

Classification

Gyttja is a coprogenous deposit formed by animals on and within lake bottom. It is a mixture of fragments of plants, diatom frustules, quartz and mica grains, siliceous spicules of Spongilla and several types of insect and crustacean exoskeletons together with pollen and cryptogam spores.[1]

Characteristics

In a fresh stat it is very soft and hydrous with a dark greenish-grey or black color, but never brown. In a dry state some gyttjas are hard and black, others are more friable and more nearly pale yellow-grey, depending on the main constituent. The organic component of gyttja is <50%.[1]

References

Limnology: Lake and River Ecosystems

Sediments from Danish lakes

Gyttja

Origin	Organic
Deposited in	Nutrient high waters
Made due to	Sunken components
Particles	Very small, clay/silt-like
Distinctive color	Yellow to grey
Structures	Layered on bottom of lake
Characteristics	Wet: soft and hydrous; Dry: friable and hard
Image	Gyttja

Contents

Classification

Characteristics

References

Gyttja