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Abstract Mantle‐induced dynamic topography (i.e., subsidence and uplift) has been increasingly recognized as an important process in foreland basin development. However, characterizing and distinguishing the effects (i.e., location, extent and magnitude) of dynamic topography in ancient foreland basins remains challenging because the spatio‐temporal footprint of dynamic topography and flexural topography (i.e., generated by topographic loading) can overlap. This study employs 3D flexural backstripping of Upper Cretaceous strata in the central part of the North American Cordilleran foreland basin (CFB) to better quantify the effects of dynamic topography. The extensive stratigraphic database and good age control of the CFB permit the regional application of 3D flexural backstripping in this basin for the first time. Dynamic topography started to influence the development of the CFB during the late Turonian to middle Campanian (90.2–80.2 Ma) and became the dominant subsidence mechanism during the middle to late Campanian (80.2–74.6 Ma). The area influenced by >100 m dynamic subsidence is approximately 400 by 500 km, within which significant (>200 m) dynamic subsidence occurs in an irregular‐shaped (i.e., lunate) subregion. The maximum magnitude of dynamic subsidence is 300 ± 100 m based on the 80.2–74.6 Ma tectonic subsidence maps. With the maximum magnitude of dynamic uplift being constrained to be 200–300 m, the gross amount of dynamic topography in the Late Cretaceous CFB is 500–600 m. Although the location of dynamic subsidence revealed by tectonic subsidence maps is generally consistent with isopach map trends, tectonic subsidence maps developed through 3D flexural backstripping provide more accurate constraints of the areal extent, magnitude and rate of dynamic topography (as well as flexural topography) in the CFB through the Late Cretaceous. This improved understanding of dynamic topography in the CFB is critical for refining current geodynamic models of foreland basins and understanding the surface expression of mantle processes.
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Lithospheric Delamination Below the North American Midcontinent Ceased Subsidence in Cratonic Basins
Abstract Cratonic lithospheres carry a long history of tectonic modifications that result in heterogeneous structures, as revealed by an increasing number of geophysical observations. The existence of cratonic basins indicates protracted periods of tectonic modification, causing subsidence within global continental interiors. An enigmatic aspect of this process is the cessation of subsidence in cratonic basins with unclear mechanisms. Here, using full‐wave ambient noise tomography, we reveal distinct seismic low‐velocity anomalies below 60 km beneath the Illinois and Michigan Basins, where subsidence terminated in the late Paleozoic to the early Mesozoic. These low‐velocity volumes, surrounded by distinctly higher velocities, are attributed to asthenospheric materials upwelling to shallow mantle depths during lithospheric foundering or delamination. This lithospheric modification may be associated with a major regional tectonic exhumation in the early Mesozoic that could have terminated basin subsidence and unroofed upper portions of basin stratigraphy. This timing coincides with the passage of this region over mantle plumes, which likely triggered lithospheric delamination and asthenospheric upwelling. Geodynamic modeling shows that the emplacement of these buoyant asthenospheric materials would lead to an uplift of about 3.5 km, sufficient to terminate the subsidence in the cratonic basins within this region. These findings document evidence of lithospheric delamination in the North American midcontinent and present important links between geodynamic drivers and geological records of the evolution of the cratonic lithosphere in North America and beyond. They also offer broader implications for understanding how deep Earth processes shape surface environments, influencing resource distribution and long‐term landscape evolution.
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- Award ID(s):
- 2244660
- PAR ID:
- 10668679
- Publisher / Repository:
- AGU
- Date Published:
- Journal Name:
- AGU Advances
- Volume:
- 7
- Issue:
- 1
- ISSN:
- 2576-604X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1029/2025AV002051
