Analog Models of Lithospheric‐Scale Rifting Monitored in an X‐Ray CT Scanner

Abstract

AbstractRifting and continental break‐up are fundamental tectonic processes, the understanding of which is of prime importance. However, the vast temporal and spatial scales involved pose major limitations to researchers. Analog tectonic modeling represents a great means to mitigate these limitations, but studying the complex internal deformation of lithospheric‐scale models remains a challenge. We therefore present a novel method for lithospheric‐scale rifting models that are uniquely monitored in an X‐ray CT scanner, which combined with digital image correlation (DIC) techniques, provides unparalleled insights into model deformation. Our first models illustrate how the degree of coupling between competent lithospheric layers, which are separated by a weak lower crustal layer, strongly impacts rift system development. Low coupling isolates the upper crust from the upper lithospheric mantle layer below, preventing an efficient transfer of deformation between both layers. By contrast, fast rifting increases coupling, so that deformation in the mantle is efficiently transferred to the upper crust, inducing either a symmetric or asymmetric (double) rift system. Furthermore, oblique divergence may lead to en echelon graben arrangements and delayed exhumation of the lower crustal layer. The successful application of our novel modeling approach, yielding these first‐order insights, provides a clear incentive to continue running lithospheric‐scale rifting models, and to apply advanced monitoring techniques to extract as much information from models as possible. There is indeed a broad range of opportunities for follow‐up studies within (and beyond) the field of rift tectonics.