Greensand

This term is specifically applied to shallow marine sediment that contains noticeable quantities of rounded greenish grains.

[1][2][3] Greensand forms in anoxic marine environments that are rich in organic detritus and low in sedimentary input.

[1][2] In Brazil, greensand refers to a fertilizer produced from glauconitic siltstone units belonging to the Serra da Saudade Formation, Bambuí Group, of Neoproterozoic/Ediacaran age.

The sedimentary provenance is from supracrustal feldsic elements on a continental margin environment with an acidic magmatic arc (foreland basin).

The term greensand was originally applied by William Smith to glauconitic sandstones in the west of England and subsequently used for the similar deposits of the Weald, before it was appreciated that the latter are actually two distinct formations separated by the Gault Clay.

Prominent seams are to be found in the Vale of White Horse, in Bedfordshire, in Kent, Surrey, the South Downs National Park,[8] elsewhere in Hampshire, the Isle of Wight, and the Jurassic Coast in Dorset.

In Roman times in Britain, coarse grits derived from the lower greensand were used to line the inner surface of mortars (grinding bowls) produced in Oxfordshire pottery kilns.

The porous properties of glauconite greensand allows for the absorption of water and minerals, making irrigation and nutrient delivery much more efficient (see soil conditioner).