The enigmatic dolomite

Abstract

There has been a great deal of progress in our knowledge on the genesis of dolomites over more than two century that has passed since the first description of dolomite. Based on inferences of the intense research relevant genetic models has been developed. After long-lasting debates it became generally accepted that large, widely extended dolomite bodies were formed from lime mud or limestone via mineral replacement, while the dolomite mineral may also precipitate as cement in pore spaces. The current paper provides a brief review on the main stages of the history of dolomite research displaying the main problems which hampered the understanding of crucial aspects of the dolomite-forming processes. The development of the proposed concepts for the interpretation of the observed phenomena and the suggested dolomitization models are also discussed. The paper presents the basic lithological, petrographic and geochemical characteristics of the dolomites and the commonly applied methods for observation and measurement of the rock properties. According to our current knowledge, it summarizes the general criteria and mechanisms of dolomitization and provides an overview about the most important dolomite-forming processes taking place in various depositional environments (marine and lacustrine) and diagenetic settings (shallow-, intermediate-, and deep burial). A review on the dolomite occurrences of Hungary and several case studies from the dolomite-rich Transdanubian Range and Tisza Megaunit are given in the second part of the article. The case studies demonstrate the every dolomite body exhibits remarkably distinct features formed as the result of multi-stage processes. These processes are mostly controlled by the host-rock properties, the consecutive dolomitization processes, the local structure evolution and the regional geodynamical setting.