The development of sheath folds in viscously stratified materials in simple shear conditions: An analogue approach

摘要: Sheath folds are highly non-cylindrical occurring in a variety of geological settings, and have been studied using different approaches. With the present work, we provide quantitative analysis generation development sheath viscously layered system simple shear conditions. The develop from an initial deflection located on viscous layer. analogue experiments investigated influence (1) variations viscosity ratio between high layer matrix (ηhvl/ηm), (2) amplitude thickness (Af/Thvl), (3) progressive (γ). results show that increases ηhvl/ηm will produce progressively less elongated folds, while Af/Thvl result more folds. We regime diagrams with for strains illustrating under which conditions form. In case original as well γ can be retrieved nature, then their geometry used to quantify effective ηhvl/ηm.