Abstract

The subsidence of foreland basins is classically thought to accelerate with time. However, a synthesis of data from numerous foreland basins recognizes a wide range of signals and rates. Our analysis investigates the influence of two broadly ubiquitous controlling factors: (1) the upward and outward growth of mountain topography and (2) the subduction velocity of the underthrust lithosphere. These two factors have contrasting subsidence signals: The former tends to be slow and decelerates, while the latter is more rapid and accelerates. The geodynamic setting of a foreland basin determines the degrees to which these components dominate the final signal of tectonically induced subsidence. In small collisional mountain ranges, the common asymmetry of subduction defines a pro- and a retro-foreland basin. Based on model experiments and the synthesized data, we demonstrate that pro-foreland basins exhibit short-lived (usually <40 m.y.), rapid (typically >0.05 km m.y.−1), accelerating subsidence histories recording only a portion of the orogenic history of the mountain range; type examples are the Carpathian foredeep and the North Alpine foreland basin. In contrast, retro-foreland basins are characterized by relatively slow (>0.05 km m.y.−1), protracted (usually >40 m.y.) subsidence that records the majority of the orogenic history; a good example is the Aquitaine foreland basin. Retro-arc foreland basins such as the Alberta Basin appear comparable to collisional retro-foreland basins. Examples where there is more protracted subsidence appear to record greater evidence of episodic loading and unloading as the topography of the range grows or shrinks in response to the balance between crustal thickening and erosion rates.

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