Drainage Reorganization, Sediment Sourcing, and Intraplate Tectonics in Western North America during the Ancestral Rocky Mountains and Laramide Orogeny

Date

2019-12

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Abstract

This dissertation explores the behavior of intraplate deformation and associated drainage reorganization in two ancient settings: The Laramide Orogeny and the Ancestral Rocky Mountains (ARM). The tools used in these investigations include section measurement, geologic mapping, paleocurrent analysis, clast-counting, sandstone petrography, detrital zircon geo- and petrochronology (i.e., U-Th-Pb, ɛHf, REE), and sediment-source modelling and mapping. All of the chapters in this dissertation document links between intraplate deformation and drainage reorganization at local- and regional/continental-scales. In Chapter II we link late-stage Laramide deformation in north-central New Mexico (and other tectonically active areas in the Laramide province) to changes in provenance along the Gulf of Mexico’s northwest margin in the middle Eocene. We propose that sediment capture during this time in the Galisteo depocenter contributed to the decreased Laramide-sourced sediment in the Gulf of Mexico and precipitated the farthest westward incursion of Appalachian-source sediment observed in the Tertiary. During late Paleozoic Ancestral Rocky Mountain (ARM) deformation, many basins within the ARM corridor experienced a high degree of sediment-source isolation, and in some proximal areas received sediment from extremely limited catchments. In Chapter III we focus on the Central Colorado Trough (CCT), in the center of the ARM corridor, which records three stages of deformation defined by dramatic shifts in provenance, and separated by major stratigraphic surfaces (i.e., unconformities and flooding surfaces). The Late Pennsylvanian stage of deformation is defined by a unimodal Cambrian-age detrital zircon age distribution the we explore the efficacy of auxiliary detrital zircon fingerprinting tools: Hf isotopes and rare-earth elements (REE). Finally, in Chapter IV we document five episodes of sediment sourcing in the ARM corridor: 1) early Paleozoic to Early Mississippian intercontinental seaway; 2) Late Mississippian to Early Pennsylvanian transcontinental fluvial integration; 3) Early Pennsylvanian to early Permian ARM basin isolation; 4) early to middle Permian tectonic quiescence and eolian infiltration; and 5) Triassic transcontinental fluvial integration. The latter four we present source maps that illustrate basement zircon sourcing from the Carboniferous through Triassic.

Description

Keywords

Intraplate tectonics, Drainage reorganization

Citation

Portions of this document appear in: Smith, Tyson M., Kurt E. Sundell, Shelby N. Johnston, Carlos N. Guilherme Andrade, Ross A. Andrea, Jordan N. Dickinson, Yiduo A. Liu, Michael Andrew Murphy, Tom J. Lapen, and Joel E. Saylor. "Drainage reorganization and Laramide tectonics in north‐central New Mexico and downstream effects in the Gulf of Mexico." Basin Research (2019).