A mixed earthy substance, consisting of carbonate of lime, clay, and possibly sand, in very variable proportions, and accordingly designated as calcareous, clayey, or sandy
A city of west-central Germany in the Ruhr Valley north of Essen. First mentioned in the ninth century, it is now highly industrialized. Population: 87,231. Earthy mixture of fine-grained minerals, which range widely in composition. Lime (calcium carbonate) is present as shell fragments of snails and bivalves, or as powder mixed with clay and silica-containing silt. Large deposits contain 80-90% calcium carbonate and less than 3% magnesium carbonate. With decreasing amounts of lime, calcium-containing marls are called clays and clayey limestones. Marls rich in potash (potassium carbonate), called greensand marls, are used as water softeners. Marls have also been used in the manufacture of insulating material and portland cement, as liming material, and in making bricks
an unconsolidated deposit of calcium carbonate mixed with clay, usually formed in freshwater lakes, but also deposited by decomposing algae in very alkaline wetlands
A soft, calcareous deposit mixed with clays, silts, and sands, often containing shells or organic remains It is common in the Gulf Coast area of the United States
A crumbly combination of limestone and clay that may be added to deficient soils Marl also occurs naturally in some French and German wine regions The finest Cote d'Or wines are grown on marl
White to gray accumulation on lake bottoms caused by precipitation of calcium carbonate (CaCO3) in hard water lakes Marl may contain many snail and clam shells, which are also calcium carbonate While it gradually fills in lakes, marl also precipitates phosphorus, resulting in low algae populations and good water clarity In the past, marl was recovered and used to lime agricultural fields
A mixed earthy substance, consisting of carbonate of lime, clay, and sand, in very variable proportions, and accordingly designated as calcareous, clayey, or sandy