Non-Uniform Crustal Subsidence due to the Infiltration of Mantle Fluids: A Case Study of the Moscow Syneclise during the Middle Devonian.

The sedimentary basin of the Moscow syneclise is located in the central part of the East European craton. It is characterized by detailed drilling coverage and an extremely high degree of geological knowledge. During the Devonian the basin was exposed to laterally non-uniform crustal subsidence after a long period of erosion. Considering the large thickness of the ancient lithosphere, this subsidence regime could only take place here in connection with rock contraction in the lower part of the crust as a result of prograde metamorphism catalyzed by the infiltration of mantle fluids. Their inflow into the lithosphere of the East European craton is evidenced by the wide occurrence of basite and kimberlite magmatism during the Devonian. The lateral distribution of subsidence throughout the syneclise changed significantly over periods of several million years. This indicates the corresponding changes in the rate of inflow of the deep fluids into the ancient lithosphere and their high surface activity. This property of the fluids enabled their rapid infiltration into the mantle lithosphere and inflow into the crust over the entire syneclise. The long-term inflow of the deep fluids into the continental lithosphere, which frequently changed in time and space, is a hitherto unknown phenomenon not related to large-scale convection in the mantle or to the rise of large plumes. It could have been the cause of the formation of many intraplate sedimentary basins on the continents. [ABSTRACT FROM AUTHOR]