Gabbro is a soil type described by Tom Stevenson (2011) as ‘a dark, coarse-grained igneous rock found in [the] Muscadet [region].’ It is also described as a dark brown, basic type parent rock giving clayey soils.

Bibliography

Tom Stevenson (2011) The Sotheby’s Wine Encyclopedia 5th Edition by Tom Stevenson (Dorling Kindersley, 2011), p.17-19.