Effects of Water on the Rheology of Dominant Minerals and Rocks in the Continental Lower Crust: A Review

Abstract

As an important part of the continental lithosphere, the continental lower crust can influence and control many important geodynamic processes, which are of great significance to the evolution of the lithosphere. Extensive plastic deformation is common in continental lower crust. There have been many studies focusing on the rheology of the continental lower crust in the past few decades. This paper provides a review on the effects of water on the rheology of dominant minerals (clinopyroxene, plagioclase and garnet) and rocks in the continental lower crust. The water contents in continental lower crustal minerals and rocks are in general rich and very heterogenous from sample to sample and region to region. Water can significantly reduce the strength of clinopyroxene, plagioclase, garnet and lower crustal rocks. Water can also have a profound influence on fabric development and slip systems in lower crustal minerals. Quantitative experimental investigations and extensive natural studies of water effect on rheology are necessary to refine the classic lithosphere strength profile models and to address the existing controversy on strength of the continental lower crust.