Towards a new class of tectonic basins: Dynamic rebound basins and lithospheric dripping

Basin-filling strata form casts of the surface topography, preserving records of tectonic events that are the foundation of our understanding of orogen dynamics today. Prevailing models for basin formation have proven useful for the interpretation of the vast majority of the sedimentary record, from continental scale deposystems like foreland basins to fault-bound deposystems along rifts and thrusts. However, the persistence of high-elevation, hinterland depocenters for millions of years, often without obvious causes of tectonic subsidence, presents a sedimentological conundrum. Non-tectonic topographic depressions on high plateaus, such as those created by aeolian excavation or volcanic damming, are finite in volume and likely to be quickly filled over geologic time. The maintenance of depression therefore generally requires the generation of new accommodation. When these enigmatic, long-lived lacustrine depocenters on high plateaus are also paired with adjacent, coeval mantle-derived magmatism, which is evidence of the disturbance of thermodynamic equilibrium at the base of the lithosphere, it bears consideration whether these basins are the surface symptoms of deeper mantle dynamics. If so, they would constitute a new class of tectonic basins: dynamic rebound basins due to lithospheric removal. Such basins should share some hallmark characteristics: anomalous patterns of intrabasinal deformation that are difficult to explain given the regional tectonic setting, convex-up subsidence curves representing the coeval acceleration of accommodation space across the entire basin, evidence of the rapid deepening of a hydrologically closed basin around the end of the depositional record, subsequent rapid rebound (basin inversion/exhumation), and mostly importantly, sedimentologic/stratigraphic patterns fundamentally inconsistent with classic models for other tectonic basins.