13-12 Structural inheritance in pro-foreland basins: examples from the Arkoma Basin, USA and Carpathians Foredeep, Poland

Session: Toe to Toe: Cordilleran Systems from Trench to Retroarc Domains

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Inherited structures (e.g., faults, geo-mechanical contrasts, lithospheric boundaries) can have varying effects on subsequent deformation and basin development. Here, we explore these variations in two archetypical pro-foreland basins: the Arkoma Basin, USA, and the Carpathian Foredeep, Poland. These two basins formed in collisional settings on lower-plate continental lithosphere attached to subducting oceanic lithosphere. Although both systems formed under regional compression, the distal segments of their thick foredeep depocenters are bound by extensional faults that accommodate up to 2 km of throw. In both cases, high flexural rigidity yields high-magnitude normal faults (>1.5 km throw) focused in a narrow zone, whereas low flexural rigidity yields lower magnitude normal faults (generally <1 km throw) distributed over broad areas. Within the Carpathian Foredeep, the high-throw normal faults correlate spatially with a reactivated lithosphere scale shear zone (the Teisseyre-Tornquist Zone located at the boundary between the East European Craton and the West European Platform); however, the presence of an analogous inherited structure in the Arkoma Basin remains uncertain. Instead, synorogenic normal faults of the Arkoma Basin appear to be segmented by an inherited structural fabric. That is, E-W-trending synorogenic normal faults decrease in throw near the intersections with NE-trending inherited basement faults. In the Arkoma Basin, synorogenic faulting and subsidence are also influenced by the presence or absence of basement plutons inferred from gravity and magnetic surveys. Where such inherited plutons exist, faulting appears to be more localized with higher throw than where inherited plutons are absent. This study highlights the need to assess different types and scales of structural inheritance in order to understand the overall effect on foreland basin development.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

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