Basins of the Rio Grande Rift: Structure, Stratigraphy, and Tectonic Setting

Variation in paleomagnetic rotations and kinematics of the north-central Rio Grande rift, New Mexico Available to Purchase
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Published:January 01, 1994
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CiteCitation
Stephen L. Salyards, James F. Ni, M. James Aldrich, Jr., 1994. "Variation in paleomagnetic rotations and kinematics of the north-central Rio Grande rift, New Mexico", Basins of the Rio Grande Rift: Structure, Stratigraphy, and Tectonic Setting, G. Randy Keller, Steven M. Cather
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Previous paleomagnetic work in the north-central Rio Grande rift (RGR) of northern New Mexico has demonstrated the presence of counterclockwise paleomagnetic rotations, possibly due to left-lateral shearing across the rift. To improve the spatial coverage and resolution of the intrarift rotation, we analyzed the late Tertiary sediments within the exposed Española Basin for paleomagnetic rotations. From five sites broadly distributed across the rift, the amount of rotation varies from little on the eastern edge to over 20° counterclockwise in the central and western rift. If interpreted as tectonic net rotation axes, the amount of rotation varies from 10 to 24°. Gently northeast plunging net rotation axis orientations in the eastern part of the rift indicate dominantly extension-related deformation. Steeper axis inclinations near the center and western part of the rift and Embudo accommodation zone indicate the presence of increased horizontal shearing in these regions. The paleomagnetic data show that the north-central Rio Grande rift is not rotating as a unit but rather consists of a number of smaller independently, counterclockwise-rotating blocks.
- accommodation zones
- block structures
- Cenozoic
- deformation
- demagnetization
- Espanola Basin
- extension tectonics
- faults
- grain size
- kinematics
- magnetic declination
- magnetic inclination
- New Mexico
- North America
- orientation
- paleomagnetism
- plate rotation
- plate tectonics
- Rio Grande Rift
- sampling
- shear
- systems
- tectonics
- Tertiary
- United States
- variations
- northern New Mexico