Fault‐related folds of variable structural styles and assemblages commonly coexist in orogenic belts with competent‐incompetent interlayered sequences. Despite their commonality, the kinematic evolution of these structural styles and assemblages are often loosely constrained because multiple solutions exist in their structural progression during tectonic restoration. We use a sandbox modeling instrument with a particle image velocimetry monitor to test four designed sandbox models with multilayer competent‐incompetent materials. Test results reveal that decollement folds initiate along selected incompetent layers with decreasing velocity difference and constant vorticity difference between the hanging wall and footwall of the initial fault tips. The decollement folds are progressively converted to fault‐propagation folds and fault‐bend folds through development of fault ramps breaking across competent layers and are followed by propagation into fault flats within an upper incompetent layer. Thick‐skinned thrust is produced by initiating a decollement fault within the metamorphic basement. Progressive thrusting and uplifting of the thick‐skinned thrust trigger initiation of the uppermost incompetent decollement with formation of a decollement fold and subsequent converting to fault‐propagation and fault‐bend folds, which combine together to form imbricate thrust. Breakouts at the base of the early formed fault ramps along the lowest incompetent layers, which may correspond to basement‐cover contacts, domes the upmost decollement and imbricate thrusts to form passive roof duplexes and constitute the thin‐skinned thrust belt. Structural styles and assemblages in each of tectonic stages are similar to that in the representative orogenic belts in the South China, Southern Appalachians, and Alpine orogenic belts.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.