Dynamic connection between Archean magma vents and Dome-and-Keel Structures

Magmatism is the main method for lithospheric cooling in Archean. It not only produces new materials, but also provides power for lithospheric deformation. The records of Archean deformation remained up to present suggest that the dome-and keel-structure related to the vertical movement are widely developed in the interiors of continental cratons at that time. However, it is not clear how the vertical structures work with the Archean magmatic activity. In order to make the study more intuitively, we made a two-dimensional numerical model in size of 879 × 400 km² based on the finite difference numerical simulation method and then tried to work out the intrusion process by setting magma conditions. The experimental results show that the magma vent array weakens the lithosphere and causes strong deformation of the lithosphere. The TTG domes are formed on the top of the magma vents. There is a negative topography between the magma channels. There is a negative topography, a depression, between the dense magma vents. During the evolution of the dome, it will expand horizontally resulting in the narrowing of the greenstone belt and the appearance of " bag" style. They constitute the dome-and keel-structure. In our study, considering magmatism as a condition of lithosphere deformation is consistent with the facts from the Archean geological background. The magma vent array, as an important factor for lithosphere deformation, provides driving force for the formation of the dome-and-keel structure.