Mantle lithosphere heterogeneities are well documented, are ubiquitous, and have often been thought to control lithosphere-scale deformation. Here, we explore the influence of deep scarring in crustal deformation in three dimensions by considering the Ouachita orogeny in the southeastern United States, an example of a continental collision where mantle structure is present but not previously linked to the regional crustal tectonics. We present state-of-the-art continental compressional models in the presence of inherited three-dimensional lithospheric structure. Our models find that the surface expression of the Ouachita orogeny is localized by, and projected from, the controlling mantle scarring, in keeping with geological and geophysical observations. We are able to produce a large-scale arcuate orogeny with associated basin development appropriate to the Ouachita orogeny, alongside smaller-scale crustal faulting related to the region. This study offers a new and alternative hypothesis to the tectonic history of the Ouachita orogeny, with previous research having focused exclusively on crustal structures. The findings have broad implications, demonstrating the important potential role of the mantle lithosphere in controlling crustal dynamics and highlighting the requirement to consider deeper structure and processes when interpreting tectonic evolution of lithospheric-scale deformation.
Bibliographical noteHeron is grateful for funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement
749664 and a DIFeREns2 COFUND Junior Research Fellowship. We thank the editor, D. Harry, E. Hopper, R. Keller, and anonymous reviewers for their helpful
comments. Pysklywec acknowledges support from a Natural Sciences and Engineering Research Council of Canada Discovery Grant and and SciNet HPC Consortium (Loken et al., 2010). We thank the Computational Infrastructure for Geodynamics which is funded by the U.S. National Science Foundation under awards EAR-0949446 and EAR-1550901 for supporting the development of ASPECT. Figure 1A was generated using Generic Mapping Tools (Wessel et al., 2013).