Shipwreck geology

摘要

Iron-cemented sands and gravels have received some attention in recent years as they turn up in many medieval buildings, mainly churches, in areas generally lacking good-quality conventional building stone. Areas of Pleistocene sands and gravels such as East Anglia and the London Basin are one example; the Tertiary outcrops of Hampshire, Sussex and Kent are another. Most people agree that irrespective of mode of origin, descriptively these iron-shot rocks fit what Lamplugh called ferricrete, a term linked with calcrete and slicrete, an iron cement taking the place of lime or silica. What process might be involved in the generation of ferricretes has remained open, but a recent description of an historic shipwreck in the Baltic may hold some clues.