Editing Rio Grande rift

{{Short description|Continental rift zone in the southwest United States}}
{{Use dmy dates|date=November 2022}}
[[Image:riogranderift localitymap.png|thumb|upright=1.5|Locality map showing the Rio Grande rift extending from southern Colorado to Chihuahua, Mexico. The [[Rio Grande]] follows this rift for much of its course.]]

The '''Rio Grande rift''' is a north-trending continental [[rift]] zone. It separates the [[Colorado Plateau]] in the west from the interior of the North American [[craton]] on the east.<ref name=chapin1994>{{Cite book |last1=Chapin |first1=Charles E. |last2=Cather |first2=Steven M.|year=1994 |chapter=Tectonic setting of the axial basins of the northern and central Rio Grande rift|title=Basins of the Rio Grande Rift: Structure, statigraphy, and tectonic setting|editor-last1=Keller|editor-first1=G. Randy|editor-last2=Cather|editor-first2=Steven M.|series=Geological Society of America Special Paper No. 291|location=Boulder, Colo.|publisher=Geological Society of America|pages=1–3 |isbn=0-8137-2291-8}}</ref> The rift extends from central [[Colorado]] in the north to the state of [[Chihuahua (state)|Chihuahua]], [[Mexico]], in the south.<ref name=kluth1994>{{Cite book |last1=Kluth |first1=C. |last2=Schaftenaar |first2=C. |year=1994 |chapter=Depth and geometry of the northern Rio Grande rift in the [[San Luis basin]], south-central Colorado |title=Basins of the Rio Grande Rift: Structure, statigraphy, and tectonic setting|editor-last1=Keller|editor-first1=G. Randy|editor-last2=Cather|editor-first2=Steven M.|series=Geological Society of America Special Paper No. 291|location=Boulder, Colo.|publisher=Geological Society of America|pages=27–37 |isbn=0-8137-2291-8}}</ref> The rift zone consists of four basins that have an average width of {{convert|50|km|mi}}.<ref name=chapin1994 /> The rift can be observed on location at [[Rio Grande National Forest]], [[White Sands National Park]], [[Santa Fe National Forest]], and [[Cibola National Forest]], among other locations.

The Rio Grande rift has been an important site for humans for a long time, because it provides a north–south route that follows a major river. The [[Rio Grande]] follows the course of the rift from southern Colorado to El Paso, where it turns southeast and flows toward the [[Gulf of Mexico]]. Important cities, including [[Albuquerque, New Mexico|Albuquerque]], [[Santa Fe, New Mexico|Santa Fe]], [[Taos, New Mexico|Taos]], [[Española, New Mexico|Española]], [[Las Cruces, New Mexico|Las Cruces]], [[El Paso, Texas|El Paso]], and [[Ciudad Juárez]], lie within the rift.

==Geology==
The Rio Grande rift represents the easternmost manifestation of widespread extension in the western U.S. during the past 35 million years. The rift consists of three major basins and many smaller basins, less than {{convert|100|km2|sqmi}}. The three major basins (from northernmost to southernmost) are the [[San Luis basin|San Luis]], [[Espanola basin|Española]], and [[Albuquerque basin|Albuquerque]] basins. The rift's northern extent is delineated by the upper Arkansas River basin between [[Leadville, Colorado|Leadville]] and [[Salida, Colorado]]. Further south, the rift is defined by a network of smaller, less topographically distinct alternating basins and ranges. The distinction between these smaller basins and those of the [[Basin and Range Province]] becomes blurred in northern [[Mexico]].<ref name=russell1994>{{Cite book|last1=Russell |first1=L.|last2=Snelson |first2=S. |date=1994|chapter=Structure and tectonics of the Albuquerque basin segment of the Rio Grande Rift: Insights from reflection seismic data|title=Basins of the Rio Grande Rift: Structure, statigraphy, and tectonic setting|editor-last1=Keller|editor-first1=G. Randy|editor-last2=Cather|editor-first2=Steven M.|series=Geological Society of America Special Paper No. 291|location=Boulder, Colo.|publisher=Geological Society of America |pages=83–112|isbn=0-8137-2291-8}}</ref><ref name= Keller1999>{{Cite journal |last1=Keller|first1=G. Randy |last2=Baldridge |first2=W. Scot |year=1999 |title=The Rio Grande Rift: a geological and geophysical overview |journal=Rocky Mountain Geology |pages=121–130 |volume=34 |number=1 |doi=10.2113/34.1.121|bibcode=1999RMGeo..34..121K }}</ref>

Basin size generally decreases to the north in the rift, though the Española covers approximately {{convert|120|km|mi}} north–south and {{convert|40|km|mi}} east–west, and the San Luis is roughly {{convert|120|by|80|km|mi}}. These basins may contain smaller units within them, such as the [[Alamosa]] basin within the San Luis, which is bounded by the San Juan and Tusas mountains on the west and the [[Sangre de Cristo Mountains]] in the east.<ref name=brister1994>{{Cite book |last1=Brister |first1=B. |last2=Gries |first2=R. |date=1994 |chapter=Tertiary stratigraphy and development of the Alamosa basin (northern San Luis basin), Rio Grande Rift, south-central Colorado |title=Basins of the Rio Grande Rift: Structure, statigraphy, and tectonic setting|editor-last1=Keller|editor-first1=G. Randy|editor-last2=Cather|editor-first2=Steven M.|series=Geological Society of America Special Paper No. 291|location=Boulder, Colo.|publisher=Geological Society of America|pages=39–58 |isbn=0-8137-2291-8}}</ref> The Albuquerque basin is the largest of the three basins, spanning {{convert|160|km|mi}} north–south and {{convert|86|km|mi}} east–west at its widest points. It is the oldest of the three major basins, and contains {{convert|7,350|m|ft}} of [[Paleogene]] clastic [[sediments]] deposited on [[Precambrian]] basement. The southernmost Albuquerque basin contains pre-rift [[volcanic rock|volcanic deposits]], while the central and northern portions contain volcanics erupted during rifting.<ref name=russell1994 /> 
[[File:Riogranderift albuquerquebasin.png|thumb|upright=2|alt=Generalized cross section of the Albuquerque basin|A generalized cross section of the Albuquerque basin from east to west. Note the [[half-graben]] geometry, [[paleozoic]] and [[mesozoic]] sediments that existed pre-rift, and the large (up to 28%) amount of extension.<ref name=russell1994 />]]
[[File:Riogranderift sanluisbasin.png|thumb|upright=2|alt=Generalized cross section of the San Luis basin|A generalized cross section of the San Luis basin from east to west. Being further north, this basin has experienced less extension (up to 12%).<ref name=chapin1994 /> Also note the lack of pre-rift sediments and thinner profile.<ref name=brister1994 />]]
In cross-section, the geometry of the basins within the rift are asymmetrical [[half-graben]]s, with major [[fault (geology)|fault]] boundaries on one side and a downward hinge on the other. Which side of the basin has the major fault or the hinge alternates along the rift. The alternation between these half-grabens occurs along transfer faults, which trend across the rift to connect the major basin-bounding faults and occur between basins or, in places, within basins. The Precambrian basement changes relief sharply in this area, from {{convert|8700|m|ft}} below sea level at the bottom of the Albuquerque basin to {{convert|3300|m|ft}} above sea level in the nearby [[Sandia Mountains]], which flanks the Albuquerque basin to the east. Flanking mountains are generally taller along the east side of the rift (although some of this relief may be [[Laramide orogeny|Laramide]] in origin).<ref name=chapin1994 />  The thickness of the [[continental crust|crust]] increases to the north beneath the rift, where it may be as much as {{convert|5|km|mi}} thicker than it is in the south. The crustal thickness underneath the rift is on average {{convert|30|–|35|km|mi}}, thinner by {{convert|10|–|15|km|mi}} than the Colorado Plateau on the west and the Great Plains to the east.<ref name=perry1987>{{Cite journal |last1=Perry |first1=Frank |last2=Baldridge |first2=W. |last3=DePaolo |first3=D. |title=Role of Asthenosphere and Lithosphere in the Genesis of Late Cenozoic Basaltic rocks from the Rio Grande rift and adjacent regions of the Southwestern United States |journal=Journal of Geophysical Research |volume=92 |issue=B9 |pages=9193–9213 |date=10 August 1987|bibcode = 1987JGR....92.9193P |doi = 10.1029/JB092iB09p09193 |url=https://zenodo.org/record/1231416 }}</ref>

[[File:Canones fault.jpg|thumb|Cañones Fault on southeastern margin of Colorado Plateau, near Abiquiú, New Mexico]]
Formation of the rift began with significant deformation and faulting with offsets of many kilometers starting about 35&nbsp;Ma.<ref>{{cite journal |last1=Grauch |first1=V.J.S. |last2=Hudson |first2=Mark R. |title=Guides to understanding the aeromagnetic expression of faults in sedimentary basins: Lessons learned from the central Rio Grande rift, New Mexico |journal=Geosphere |date=2007 |volume=3 |issue=6 |pages=596 |doi=10.1130/GES00128.1|doi-access=free |bibcode=2007Geosp...3..596G }}</ref>  The largest-scale manifestation of rifting involves a pure-shear rifting mechanism, in which both sides of the rift pull apart evenly and slowly, with the lower crust and [[upper mantle (Earth)|upper mantle]] (the [[lithosphere]]) stretching like [[Taffy (candy)|taffy]].<ref name=wilson2005 /><ref>{{Cite journal |last=Fleck |first=John |title=Study Sheds Light on 30 Million Years of Rio Grande Valley Stretching |journal=Albuquerque Journal |date=24 February 2005 }}</ref><ref>{{Cite journal |last=Hill |first=Karl |date=25 February 2005 |title=The Rio Grande Rift: a continent "stretched like taffy" |journal=NMSU News Release }}</ref>  This extension is associated with very low seismic velocities in the upper mantle above approximately {{convert|400|km|mi}} depth associated with relatively hot mantle and low degrees of partial melting.<ref>{{Cite journal |last1=Gao |first1=W. |last2=Grand |first2=S. |last3=Baldridge |first3=S. |last4=Wilson |first4=D.|last5=West |first5=M. |last6=Ni |first6=J. |last7=Aster |first7=R. |title=Upper mantle convection beneath the central Rio Grande rift imaged by P and S wave tomography |journal=J. Geophys. Res. |volume=109 |issue=B3 |pages=B03305 |doi=10.1029/2003JB002743 |year=2004 |bibcode = 2004JGRB..109.3305G }}</ref> This intrusion of the [[asthenosphere]] into the [[lithosphere]] and [[continental crust]] is thought to be responsible for nearly all of the volcanism associated with the Rio Grande rift.

The sedimentary fill of the basins consists largely of [[alluvial fan]] and [[mafic]] volcanic flows. The most [[alkalic]] lavas erupted outside the rift.<ref name=baldridge1984>{{Cite book |last1=Baldridge |first1=W. |last2=Olsen |first2=K. |last3=Callender |first3=J. |year=1984 |chapter=Rio Grande Rift: Problems and Perspectives |title=New Mexico Geological Society Guidebook, 35th field conference |pages=1–11}}</ref> The sediments that were deposited during rifting are commonly known as the [[Santa Fe Group (geology)|Santa Fe Group]]. This group contains [[sandstone]]s, [[Conglomerate (geology)|conglomerates]], and volcanics. [[Aeolian processes|Aeolian deposits]] are also present in some basins.<ref name=chapin1994 /><ref name=kluth1994 />

The Rio Grande rift is intersected in northern New Mexico by the NE-SW trending [[Jemez Lineament]] which extends well into [[Arizona]]. The lineament is defined by aligned volcanic fields and several [[calderas]] in the area, including the [[Valles Caldera National Preserve]] in the [[Jemez Mountains]]. The Jemez Lineament is thought to be a hydrous subduction zone scar, separating [[Precambrian]] [[basement rock]] of the [[Yavapai orogeny|Yavapai]]-[[Mazatzal orogeny|Mazatzal]] transition zone from the Mazaztl Province proper.<ref name="aldrich1986">{{cite journal|last=Aldrich Jr.|first=M. J.|title=Tectonics of the Jemez Lineament in the Jemez Mountains and Rio Grande Rift|journal=Journal of Geophysical Research|year=1986|volume=91|issue=B2|pages=1753–1762|doi=10.1029/JB091iB02p01753|bibcode = 1986JGR....91.1753A |url=https://zenodo.org/record/1231400}}</ref><ref name="wk2007">{{cite journal |last1=Whitmeyer |first1=Steven |last2=Karlstrom |first2=Karl E. |journal=Geosphere |date=2007 |volume=3 |issue=4 |pages=220 |doi=10.1130/GES00055.1 |title=Tectonic model for the Proterozoic growth of North America|doi-access=free }}</ref> Also on the Colorado Plateau but further north lies the [[San Juan volcanic field]] in the [[San Juan Mountains]] of Colorado.

The youngest eruptions in the rift region are in the [[Carrizozo Malpais|Valley of Fires]], New Mexico, and are approximately 5,400&nbsp;years old.<ref>{{Cite web |last=Aber |first=James S. |title=Rio Grande Rift |url=http://academic.emporia.edu/aberjame/struc_geo/rio/rio.htm |access-date=8 February 2006 |archive-url=https://web.archive.org/web/20060129141006/http://academic.emporia.edu/aberjame/struc_geo/rio/rio.htm |archive-date=29 January 2006 |url-status=dead |work=GO 568 Structural Geology }}</ref><ref>{{Cite web |last=Veatch |first=Steven Wade |title=The Rio Grande Rift |date=20 March 1998 |url=http://home.att.net/~sgeoveatch/rio_grande_rift.htm |access-date=8 February 2006 |url-status=dead |archive-url=https://web.archive.org/web/20051220215216/http://home.att.net/~sgeoveatch/rio_grande_rift.htm |archive-date=20 December 2005 }}</ref>  The [[Socorro, New Mexico]], region of the central rift hosts an inflating mid-crustal sill-like magma body at a depth of 19&nbsp;km that is responsible for anomalously high earthquake activity in the vicinity, including the largest rift-associated earthquakes in historic times (two events of approximately magnitude 5.8) in July and November 1906.<ref>{{Cite journal |last=Reid |first=H.G. |title=Remarkable earthquakes in central New Mexico in 1906 and 1907 |journal=Bull. Seismol. Soc. Am. |volume=1 |pages=10–16 |year=1911 |issue=1 |doi=10.1785/BSSA0010010010 |bibcode=1911BuSSA...1...10R }}</ref><ref>{{Cite journal |last1=Sanford |first1=A.R. |first2=R.S. |last2=Balch |first3=K.W. |last3=Lin |title=A seismic anomaly in the Rio Grande Rift near Socorro, New Mexico |volume=78 |place=Socorro, NM |pages=17 |publisher=New Mexico Institute of Mining and Technology Geophysics Open-File Report |year=1995 }} Abstract at: {{Cite journal|doi=10.1785/gssrl.66.2.15 |title=Annual Meeting |journal=Seismological Research Letters |date=1995 |volume=66 |issue=2 |at=page 44 of 15–61}}
</ref><ref>{{Cite journal |last1=Schlue |first1=J. |last2=Aster |first2=R. |last3=Meyer |first3=R. |title=A lower-crustal extension to a mid-crustal magma body in the Rio Grande Rift, New Mexico |journal=J. Geophys. Res. |volume=101 |issue=B11 |pages=25,283–25,291 |year=1996 |doi=10.1029/96JB02464 |bibcode = 1996JGR...10125283S }}</ref>  Earth and space-based geodetic measurements indicate ongoing surface uplift above the Socorro magma body<ref>{{Cite web |url=http://www.ees.nmt.edu/Geop/Museum_Posters/NMseismology.html |title=Socorro Magma Body |url-status=dead |archive-url=https://web.archive.org/web/20100615041810/http://www.ees.nmt.edu/Geop/Museum_Posters/NMseismology.html |archive-date=15 June 2010 }}</ref> at approximately 2&nbsp;mm/year.<ref>{{Cite journal |last1=Fialko |first1=Yuri |last2=Simons |first2=Mark |year=2001 |title=Evidence for on-going inflation of the Socorro magma body, New Mexico, from interferometric synthetic aperture radar imaging |journal=Geophysical Research Letters  |volume=28 |issue=18 |pages=3549–3552 |doi=10.1029/2001GL013318 |bibcode=2001GeoRL..28.3549F |doi-access=free }} <small style="color:blue;"> (Doi fails redirect.)</small></ref>

<gallery widths="250px" heights="250px">
File:Riogranderift deepXsection.png|alt=Generalized cross section of the Rio Grande Rift, showing lithospheric and asthenospheric structure.|A generalized cross section of the Rio Grande Rift, showing [[Lithosphere|lithospheric]] and [[Asthenosphere|asthenospheric]] structure. Note the magma lenses and volcanics caused by the welling up of the asthenosphere into the crust, and the thinning of the lithosphere<ref name=baldridge1984 />

Image:RioGrande Rift RISTRA Seismic Image.jpg|Deep seismic image of the Rio Grande rift compiled from the seismic transect shown in the previous figure, showing inferred mantle flow and imaged crust-mantle ([[Mohorovičić discontinuity|Moho]]) topography (after Wilson et al.)(2005).<ref name=wilson2005 >{{Cite journal|last1=Wilson|first1=David|first2=Richard|last2=Aster|first3=Michael|last3=West|first4=James|last4=Ni|first5=Steve|last5=Grand|first6=Wei|last6=Gao|first7=W. Scott|last7=Baldridge|first8=Steve|last8=Semken|first9=Paresh|last9=Pate|title=Lithospheric structure of the Rio Grande rift|journal=Nature|volume=433|issue=7028|pages=851–855|date=24 February 2005|pmid=15729338|doi=10.1038/nature03297|bibcode = 2005Natur.433..851W  |s2cid=4387908}}</ref>\

File:Riogranderift timeline.png|alt=Timeline for extension and volcanism in the area of the Rio Grande rift.|A brief timeline showing extension and volcanism in the Rio Grande rift area. The end of the Laramide orogeny was followed by volcanism and then extension. Changes in lava chemistry are also found, resulting from changes in magmatic sources.<ref name=morgan1984>{{Cite book|last1=Morgan|first1=P.|last2=Golombek|first2=M.|year=1984|chapter=Factors controlling the phases and styles of extension in the northern Rio Grande rift|title=New Mexico Geological Society Guidebook, 35th field conference|pages=13–20}}</ref>
</gallery>

==Geologic history==
[[Image:RioGrande Rift RISTRA.jpg|thumb|upright=1.5|Seismic profile from the Rio Grande Rift Seismic Transect (RISTRA) experiment crossing the rift system, with [[Cenozoic]] extended terrain of the rift and southern Great Basin tectonic provinces indicated.]]
The Rio Grande rift's [[tectonics|tectonic]] evolution is fairly complex.  The fundamental change in the western margin of the North American plate from one of [[subduction]] to a [[transform fault|transform boundary]] occurred during [[Cenozoic]] time.  The [[Farallon plate]] continued to be subducted beneath western North America for at least 100&nbsp;million years during Late [[Mesozoic]] and early [[Cenozoic]] time. [[Deformation (mechanics)|Compressional and transpressional deformation]] incurred by the [[Laramide Orogeny]] lasted until about 40&nbsp;[[Annum|Ma]] in New Mexico.<ref name=Seager1986>{{cite journal |last1=Seager |first1=W.R. |last2=Mack |first2= G.H. |year=1986 |title=Memoir 41: Laramide Paleotectonics in southern New Mexico |journal=Paleotectonics and Sedimentation in the Rocky Mountain Region: Tulsa, Oklahoma|volume=155 | publisher= American Association of Petroleum Geologists  |pages=669–685 | url = http://archives.datapages.com/data/specpubs/structu1/data/a155/a155/0001/0650/0669.htm }}</ref><ref name="Chapin1981">{{cite journal |last1=Chapin |first1=C.E. |last2=Cather |first2=S.M. |title=Eocene tectonics and sedimentation in the Colorado Plateau-Rocky Mountain area |journal=Arizona Geological Digest |volume=4 |pages=173–198}}</ref><ref name=Karlstrom1993>{{cite journal |last1=Karlstrom |first1=K.E. |last2= Daniel |first2=C. G. |last3=Taira |first3=Asahiko |year=1993 |title=Restoration of Laramide right-lateral strike-slip in northern New Mexico by using Proterozoic piercing points |journal= Geology |volume=21 |issue=2 |pages=188–211|bibcode = 1993Geo....21..188C |doi = 10.1130/0091-7613(1993)021<0188:TPUOHH>2.3.CO;2 }}</ref> This deformation may have been a result of the coupling between the subducting Farallon plate and the overlying [[North American Plate]]. Crustal thickening occurred due to Laramide compression. After the Laramide Orogeny and until 20&nbsp;Ma, a major period of volcanic activity occurred throughout the southwestern United States.  Injection of hot magmas weakened the lithosphere and allowed for later extension of the region.<ref name= Morgan1986>{{cite journal |last1=Morgan |first1= P. |last2= Sedger |first2=W.R. |last3= Golombek |first3=M.P. |title=Cenozoic thermal, mechanical, and tectonic evolution of the Rio Grande rift |year=1986 |journal= Journal of Geophysical Research |volume=91 |pages=6263–6276|bibcode = 1986JGR....91.6263M |doi = 10.1029/JB091iB06p06263 }}</ref>

[[Cenozoic]] [[Extension (geology)|extension]] started about 30&nbsp;million years ago (Ma).  There are two phases of extension observed: late [[Oligocene]] and middle [[Miocene]].<ref name=Seager1984>{{cite journal |last1=Seager |first1=W. R. |last2=Shafiqullah |first2=M. |last3= Hawley |first3= J. W. |last4= Marvin |first4= R. F. |year= 1984 |title=New K-Ar dates from basalts and the evolution of the southern Rio Grande Rift |journal=Geological Society of America Bulletin |volume= 95 |issue=1 |pages= 87–99 |doi=10.1130/0016-7606(1984)95<87:nkdfba>2.0.co;2|bibcode=1984GSAB...95...87S }}</ref> The first period of extension produced broad,  shallow basins bounded by low-angle faults. The crust may have been extended as much as 50% during this episode. Widespread [[magma]]tism in mid-[[Cenozoic]] time suggests that the [[lithosphere]] was hot,  the brittle-ductile transition was relatively shallow.<ref name=Morgan1986 /> There is evidence that the second period of extension began earlier in the central and northern Rio Grande rift than in the south.<ref name=chapin1994 /> A third period of extension may have begun in the early [[Pliocene]].<ref name="golombek_1983">{{cite journal |last1=GOLOMBEK |first1=MATTHEW P. |title=Geology, structure, and tectonics of the Pajarito fault zone in the Española basin of the Rio Grande rift, New Mexico |journal=Geological Society of America Bulletin |date=1983 |volume=94 |issue=2 |pages=192 |doi=10.1130/0016-7606(1983)94<192:gsatot>2.0.co;2|bibcode=1983GSAB...94..192G }}</ref>

One theory is that the Colorado Plateau acts as a semi-independent microplate<ref name= Steiner1988>{{cite journal |last= Steiner |first= M. B. |year= 1988 |title= Paleomagnetism of the late Pennsylvanian and Permian: A test of the rotation of the Colorado Plateau |journal= Journal of Geophysical Research |volume= 93 |issue= B3 |pages=2201–2215|bibcode = 1988JGR....93.2201S |doi = 10.1029/JB093iB03p02201 }}</ref> and one way of explaining the creation of the Rio Grande rift is by the simple rotation of the Colorado Plateau 1-1.5° in a clockwise direction relative to the North American craton.<ref name=chapin1994 /> Other explanations that have been offered are that the extension is driven by mantle forces, such as large-scale mantle upwelling<ref name="moucha-etal-2008">{{cite journal |last1=Moucha |first1=Robert |last2=Forte |first2=Alessandro M. |last3=Rowley |first3=David B. |last4=Mitrovica |first4=Jerry X. |last5=Simmons |first5=Nathan A. |last6=Grand |first6=Stephen P. |title=Mantle convection and the recent evolution of the Colorado Plateau and the Rio Grande Rift valley |journal=Geology |date=2008 |volume=36 |issue=6 |pages=439 |doi=10.1130/G24577A.1|bibcode=2008Geo....36..439M }}</ref> or small-scale mantle convection at the edge of the stable craton;<ref name="van-wijk-etal-2008">{{cite journal |last1=van Wijk |first1=J. |last2=van Hunen |first2=J. |last3=Goes |first3=S. |title=Small-scale convection during continental rifting: Evidence from the Rio Grande rift |journal=Geology |date=2008 |volume=36 |issue=7 |pages=575 |doi=10.1130/G24691A.1|bibcode=2008Geo....36..575V }}</ref> collapse of over-thickened continental crust;<ref name="eaton-1986">{{cite journal |last1=Eaton |first1=Gordon P. |title=A tectonic redefinition of the Southern Rocky Mountains |journal=Tectonophysics |date=December 1986 |volume=132 |issue=1–3 |pages=163–193 |doi=10.1016/0040-1951(86)90031-4|bibcode=1986Tectp.132..163E }}</ref> initiation of transform faulting along the western margin of the North American plate;<ref name="dickinson-snyder-1979">{{cite journal |last1=Dickinson |first1=William R. |last2=Snyder |first2=Walter S. |title=Geometry of Subducted Slabs Related to San Andreas Transform |journal=The Journal of Geology |date=November 1979 |volume=87 |issue=6 |pages=609–627 |doi=10.1086/628456|bibcode=1979JG.....87..609D |s2cid=129169733 }}</ref> or detachment of a fragment of the Farallon plate beneath the Rio Grande region that enhanced asthenospheric upwelling in the slab window.<ref name="ricketts-etal-2016">{{cite journal |last1=Ricketts |first1=Jason W. |last2=Kelley |first2=Shari A. |last3=Karlstrom |first3=Karl E. |last4=Schmandt |first4=Brandon |last5=Donahue |first5=Magdalena S. |last6=van Wijk |first6=Jolante |title=Synchronous opening of the Rio Grande rift along its entire length at 25–10 Ma supported by apatite (U-Th)/He and fission-track thermochronology, and evaluation of possible driving mechanisms |journal=Geological Society of America Bulletin |date=March 2016 |volume=128 |issue=3–4 |pages=397–424 |doi=10.1130/B31223.1|bibcode=2016GSAB..128..397R }}</ref>

==See also==
* [[Caja del Rio]]
* [[Geologic timeline of Western North America]]
* [[Lucero volcanic field]]
* [[Pajarito Plateau]]
* [[Potrillo volcanic field]]
* [[Rio Grande Trail]]

==References==
{{Reflist}}

{{Faults}}
{{Authority control}}

{{DEFAULTSORT:Rio Grande Rift}}
[[Category:Cenozoic rifts and grabens]]
[[Category:Rio Grande]]
[[Category:Basin and Range Province]]
[[Category:Geologic provinces of Colorado]]
[[Category:Geology of New Mexico]]
[[Category:Geology of Texas]]
[[Category:Geology of Mexico]]