Radiographic study of the distribution of boron in recent mollusc shells

Studies have been made of the boron content and distribution in recent Mytilus edulis shells by mapping the alpha particle distribution produced by the ¹⁰B (n,α)⁷Li reaction using cellulose nitrate track detectors. Boron is concentrated in the inorganic parts of the shell matrix and is enriched in aragonite relative to calcite by a factor of 1.5–2. The B contents in different parts of individual shells and in different specimens from a given locality are well defined, particularly for the aragonite layer. A correlation was found between the B in the aragonite layer and the salinity of the water in which the shells grew. The method shows promise as a means of using the boron content of fossil shells to determine paleosalinity.