Stratigraphy and Structure of the Española Basin, Rio Grande Rift, New Mexico
- Robert E. Riecker
Published Online: 21 MAR 2013
Copyright © 1979 by the American Geophysical Union.
Rio Grande Rift: Tectonics and Magmatism
How to Cite
Manley, K. (1979) Stratigraphy and Structure of the Española Basin, Rio Grande Rift, New Mexico, in Rio Grande Rift: Tectonics and Magmatism (ed R. E. Riecker), American Geophysical Union, Washington, D. C.. doi: 10.1029/SP014p0071
- Published Online: 21 MAR 2013
- Published Print: 1 JAN 1979
Print ISBN: 9780875902142
Online ISBN: 9781118664988
- Basin boundary faults;
- Espanola basin structure;
- Espinaso volcanics;
- Galisteo and el rito formations;
- Intra-basin faults;
- Rio Grande age;
The Española basin, part of the Rio Grande rift in northern New Mexico, contains sedimentary and volcanic rocks of Eocene to Quaternary age. The onset of rifting, based on evidence from north and south of the basin, is generally considered middle to late Oligocene. Deposits of late Oligocene and early Miocene age extend beyond the margins of the present basin, offering no evidence that boundary faults existed at that time. The basin was probably a shallow depression between the eastward-tilting Nacimiento uplift and the westward-tilting Sangre de Cristo Mountains. Extensional faulting and volcanism near the western basin margin began in mid-Miocene time. Mid-Miocene to Pliocene rocks lap onto the Precambrian rocks of the Sangre de Cristo Mountains and have minor offsets along late Miocene to Pliocene faults.
The northeast-trending Velarde graben, with stratigraphic offset of as much as 360 m, formed in the central Española basin in early Pliocene time. The western side of the graben is partially bounded by the Pajarito fault zone, along which the Quaternary Bandelier Tuff has been offset. Early Pliocene deformation waned about 4 m.y. ago. A series of broad penecontemporaneous surfaces were cut across older basin-fill deposits; one of these is the Ortiz surface in the Santo Domingo subbasin. Overlying these surfaces are several formations 2.9 to 2.0 m.y. old. The Rio Grande was apparently established in conjunction with the Pliocene erosion. Volcanic activity in the Cerros del Rio field 3 to 2 m.y. ago periodically dammed the river, which downcut in the late Quaternary until the present topographic Española basin was formed.