Geochemistry of the soll facies of the Lower Globigerina Limestone formation, Malta

Abstract

Rock from the "soll" seams of the Lower Globigerina Limestone Formation is distinguishable from 'franka" because of its characteristic honeycomb weathering. However, when freshly quarried, "soll" limestone, aninferior building material, is not so readily recognizable. This study was aimed at characterizing "soll" on the basis of its inorganic geochemistry. It is shown that "soll" has a significantly higher silicon content than normal "franka". The silica content of "soll', which is a measure of its clay content, is typically less than 5%. Therefore, the traditional belief that "soll" is a limestone which is rich in clay is untenable. The silicon content may be useful in differentiating "soll" limestone from 'franka ". Besides that in silicon, other elemental anomalies are found associated with the "soll" facies of the Lower Globigerina and also with "soll ahdar ", a stratigraphically related grey-green variety.