Late Cretaceous Sevier and Laramide orogenies in Wyoming-Utah-Colorado, USA: Insight from basin subsidence history

The spatial and temporal variations of basin subsidence could potentially provide critical information for investigating the history of orogeny and deep mantle processes. However, due to the complexity of the formation mechanism of the Western Interior Basin, the factors controlling the basin subsidence has long been debated. Here, by reconstructing a high-resolution chronostratigraphic framework for the Upper Cretaceous strata and restoring the subsidence history of the basin, we analyze the control of the Sevier and Laramide orogenies on the Late Cretaceous evolution of the basin in the Wyoming-Utah-Colorado, and reveal the contemporary migration pattern of long-wavelength dynamic subsidence. During Cenomanian to Santonian time, thrusting events were active on the western margin of the basin, along which NS-trending long-wavelength subsidence center developed. By early Campanian (ca. 82 Ma), thrusting events developed into NW trend, and the center of long-wavelength subsidence shifted in the same orientation and gradually migrated to the center of the basin. Starting in the Maastrichtian (ca. 72 Ma), the NW-trending thrusting events migrates northeastward, roughly consistent with coeval long-wavelength subsidence center. Our results show that the former thrust event is related to Sevier orogeny, while the latter should be related to the Laramide orogeny. The initial timing of the Laramide deformation could start at as early as 82 Ma. This finding suggests that migrations of both long-wavelength subsidence center and Laramide deformation are driven by changes of Farallon subduction direction from eastward to northeastward and subduction angle from deep to flat. Our work shows how the subsidence history precisely records the timing and trajectory of Sevier and Laramide orogenies and dynamic topography, providing valuable insights for future three-dimensional modeling of dynamic subsidence in the Western Interior Basin.