The results of electron microscopic studies of the Lower Permian ooid dolomites (South Timan)

The article presents the results of studies of the Lower Permian dolomites containing ooids. They outcrop in the northeastern part of the East European Platform and are confined to the upper-middle reaches of the Vychegda River (South Timan, near the mouth of the Nem River). Electron microscopic studies have revealed the complex structure of the dolomites conditioned by their heterogeneous nature. We found ooids, remains of microphytophossils (microphytoliths), and biomorphoses from various faunal remains. The results of the conducted research can be interpreted in different ways. On the one hand, traces of bacterial communities were found in the structure of zooids (oolites) from the studied rocks, indicating their biochemogenic nature. In this case, the microbiota, by changing the environment, could contribute to the deposition of protodolomite phases in the course of its vital activity. On the other hand, the dolomites contain mineral phases testifying to the multiphase formation of rocks.