THE ROLE OF CURVATURE IN EXFOLIATION DOME DYNAMICS: INSIGHTS FROM FIELD DATA AND FORMAL SURFACE CLASSIFICATION

The curvature of rock domes is hypothesized to play a pivotal role in exfoliation by influencing internal stress distributions, which drive fracture propagation and set slab thickness. As described by Martel (2011, 2006), convex surfaces concentrate tensile stresses that promote the formation and propagation of exfoliation joints, with higher curvature associated with thinner, more closely spaced slabs. In addition to these models of topographic stress fields, studies by Collins & Stock (2016) and Eppes & Keanini (2017) suggest curvature may influence thermal gradients that accelerate exfoliation processes. These findings underscore the centrality of curvature in shaping exfoliation dome morphology and provide a framework for predictive modeling of dome stability and evolution. Integrating curvature metrics with geospatial tools and numerical modeling offers a promising avenue for advancing understanding of exfoliation mechanics and broader geomorphic processes. To our knowledge, however, these hypotheses have not been tested with field data across a wide range of scales.

Preliminary data examining ‘dome scale’ curvature (Moser, 2017; Weiserbs, 2017) suggest regions of higher curvature consistently exhibit thinner, more closely spaced slabs and enhanced weathering rates, emphasizing surface geometry’s role in controlling exfoliation dynamics. Building on that work, we use tools from formal surface theory and spectral analysis (Klema, 2023) to calculate the full curvature tensor at points along the surface of three actively exfoliating granite domes in the southeastern US. We see that previously identified relationships between curvature and slab thickness hold down to characteristic depths of diurnal thermal penetration (~25 cm) but break down at greater depths. This suggests that, while shallow surface fractures are likely sensitive to daily temperature variation, dome evolution reflects a more complex superposition of forcings acting across spatial and temporal scales.

Our results suggest spectral decompositions of topographic curvature, combined with focused field studies, provide a means to disentangle these forcing mechanisms and better understand the long-term dynamics of exfoliating domes.