Calcareous clay is a soil type described by Tom Stevenson (2011) as ‘argillaceous soil with carbonate of lime content that neutralizes the clay’s intrinsic acidity. Its low temperature also delays ripening, so wines produced on this type of soil tend to be more acidic.’

Bibliography

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