Dextral Shear along the Eastern Margin of the Colorado Plateau: A Kinematic Link between Laramide Contraction and Rio Grande Rifting (Ca. 75–13 Ma)

• Published in: The Journal of geology 2002-05, Vol.110 (3), p.305-324
• Main Authors: Wawrzyniec, Tim F., Geissman, John W., Melker, Marc D., Hubbard, Mary
• Format: Article
• Language: English
• Subjects: Axes of rotation; Counter rotation; Demagnetization; Kinematics; Magnetization; Orogeny; Plate tectonics; Plateaus; Population parameters; Population structure
• ISSN: 0022-1376; 1537-5269
• DOI: 10.1086/339534

Kinematic data associated with both Laramide‐age and ‐style and Rio Grande rift‐related structures show that the latest Cretaceous to Neogene interaction between the Colorado Plateau and the North American craton was dominantly coupled with a component of dextral shear. Consistent with earlier studies, minor‐fault data in this study yielded results of varied kinematics. Inverted to a common northeast‐oriented hemisphere, the mean trend of kinematic shortening associated with Laramide‐age structures is \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $056^{\circ }\pm 6$ \end{document} °. Inverted to a common west‐oriented hemisphere, the mean trend of kinematic extension associated with Neogene rifting is \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $300^{\circ }\pm 34$ \end{document} °. The observed dispersion in these directions suggests multiphase deformation, particularly during rifting, along the margin of the plateau since the latest Cretaceous. These data were evaluated using a simple two‐dimensional transcurrent kinematic model; assuming a minimal importance of strain partitioning, a mean trend of convergence between the Colorado Plateau and the North American craton was estimated to be \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefaul