Structurally Controlled Hydrothermal Dolomitization:A New Model in International Carbonates Field

Dolomitization is very complex and there are about 10 traditional dolomitization models. A new model advocated by Lavoie: structurally controlled dolomitization is popular all over the world. The model is looked as an important proceeding in international carbonates exploration and research. The principle is that deep thermal fluid moves along faults extended to depth into shallow limestones and then moves laterally because of the obstruction of the dense clastics above and makes the limestones dolomitization. According to an example analysis of hydrothermal dolomitization in the Lower Silurian Sayabec Formation in northern Gaspe-Matapedia (Quebec), the authors present the principles of structurally controlled hydrothermal dolomitization, and summarize its characteristics and controlling factors. It is found that hydrothermal dolomites formed by structurally controlled hydrothermal dolomitization are the favorable reservoirs of oil and gas, and they are also associated with lead-zinc deposits. The authors assume that partial carbonates reservoirs and lead-zinc deposits in South China have the similar geological background to this new model by initial research. In short, the appearance of the model not only explains the diversity and complexity of dolomite genesis, but also is of referential significance for genesis analysis and exploration of the analogous deposits in China.