Dolomityzacja w wapieniach oksfordu okolic Barcina (Kujawy)
Abstract
DOLOMITIZATION IN OXFORDIAN LIMESTONES IN THE VICINITIES OF BARCIN (KUJAWY)
Summary
The paper deals with dolomitization in Oxfordian limestones in the vicinities of Barcin (Kujawy). The specific character of the studied locality is determined by the neighborhood of salt diapir of the Zalesie structure. Such association of dolomitization and salt diapir often bears significant influence on genetic interpretation of dolomitization processes.
The presented data on development and geochemistry of dolomite bodies show that in the case of limestones from the vicinities of Barcin the dolomitization has been proceeding with contribution of fresh water in zone of mixing with water enriched in magnesium ion (pore water squeezed out of overlaying marly-mudstone rock complex). Weakly alkaline character of dolomitizing solutions is indicated by cooccurrence of dolomite rhombohedrons and chalcadony sponge spicules (Fig. 2).
Chemical analyses showed the content of strontium to be two times higher in calcite than dolomite, which is typical for conditions of mutual equilibrium with common solution. This makes it possible to treat the phenomena of dolomitization and final cementation of limestones from the Barcin area as a single process.
Summary
The paper deals with dolomitization in Oxfordian limestones in the vicinities of Barcin (Kujawy). The specific character of the studied locality is determined by the neighborhood of salt diapir of the Zalesie structure. Such association of dolomitization and salt diapir often bears significant influence on genetic interpretation of dolomitization processes.
The presented data on development and geochemistry of dolomite bodies show that in the case of limestones from the vicinities of Barcin the dolomitization has been proceeding with contribution of fresh water in zone of mixing with water enriched in magnesium ion (pore water squeezed out of overlaying marly-mudstone rock complex). Weakly alkaline character of dolomitizing solutions is indicated by cooccurrence of dolomite rhombohedrons and chalcadony sponge spicules (Fig. 2).
Chemical analyses showed the content of strontium to be two times higher in calcite than dolomite, which is typical for conditions of mutual equilibrium with common solution. This makes it possible to treat the phenomena of dolomitization and final cementation of limestones from the Barcin area as a single process.