32 From the Sevier to Laramide: Connecting Hinterland to Foreland by Tectonics, Structure, and Sedimentation

Thursday, 17 March 2022
8:00 AM - 12:00 PM
CBC-A 112

PALEOGEOGRAPHIC EVOLUTION OF THE LATE CRETACEOUS NORTH AMERICAN CORDILLERAN FORELAND BASIN: AN EXEMPLAR OF THE COMBINED INFLUENCE OF TECTONICS, SEA LEVEL, AND SEDIMENT SUPPLY THROUGH TIME

Paper number: 32-12
Program: Theme Sessions
Time: 11:20 AM – 11:40 AM

Authors

Abstract

The stratigraphic record from the North American Cordilleran foreland basin (CFB) serves as a critical archive of how tectonics, sea-level and sediment supply interacted throughout the geologic past, providing valuable insights into the formation and filling of foreland basins. By integrating a range of stratigraphic, sedimentologic, and geochronological datasets from previous stratigraphic research and new data, the roles of various geological processes within the CFB are better constrained, especially more enigmatic subcrustal processes probably related to large-scale mantle flows. This study summarizes the complex paleogeographic evolution of the central part of the CFB in 25 temporally constrained paleogeographic maps illustrating high-resolution shoreline history (location and migration trend) and distribution of gross depositional environments through the Late Cretaceous.

Detailed stratigraphic synthesis and paleogeographic maps of the CFB indicate that sediment fill of the CFB was subject to complex interactions of tectonics (both local and regional scale and both crustal and subcrustal processes), eustasy, and sediment supply. Although crustal processes such as flexural subsidence caused by loading of the Sevier fold-thrust belt and local Laramide structures has long been considered as the overriding subsidence mechanism for the development of the CFB, the effect of mantle-induced dynamic topography (uplift and subsidence) is evident in newly developed paleogeographic maps here. Subcrustal processes such as mantle flow, possibly associated with enhanced coupling by subduction of an oceanic plateau (i.e., the conjugate Shatsky rise) attached to the Farallon plate, were documented as an important mechanism influencing the subsidence/uplift and sediment dispersal patterns in the CFB since at least ~ 85 Ma. High-resolution reconstruction of the geohistory of the CFB through holistic approaches will greatly advance our understanding of the roles of different allogenic factors in sediment filling of the CFB and enable us to better use the stratigraphic record of foreland basins as important archives of paleoenvironmental evolutions and the interaction between surficial and deep Earth processes through geological time.

Geological Society of America Abstracts with Programs. Vol. 54, No. 2

doi: 10.1130/abs/2022CD-374005

© Copyright 2022 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.