Rio Grande rift - wikipedia Rio Grande rift 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. The rift extends from central Colorado in the north to the state of Chihuahua, Mexico in the south. The rift zone consists of four basins that have an average width of 50 kilometers. The rift can be observed on location at Rio Grande National Forest, White Sands National Monument, 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, Santa Fe, Taos, Española, Las Cruces, El Paso, and Ciudad Juárez lie within the rift. Contents 1 Geology 2 Geologic history 3 See also 4 References 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 100 km. The three major basins ( from northernmost to southernmost ) are the San Luis, Española, and Albuquerque basins. 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. Basin size generally decreases to the north in the rift, though the Española covers approximately 120 km north - south and 40 km east - west, and the San Luis is roughly 120 km by 80 km. 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. The Albuquerque basin is the largest of the three basins, spanning 160 km north - south and 86 km east - west at its widest points. It is the oldest of the three major basins, and contains 7,350 m of Paleogene clastic sediments deposited on Precambrian basement. The southernmost Albuquerque basin contains pre-rift volcanic deposits, while the central and northern portions contain volcanics erupted during rifting. 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. 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 % ). Also note the lack of pre-rift sediments and thinner profile. The southernmost Rio Grande Rift broadens, becoming more complex in structure and physiographically indistinguishable from the adjoining Basin and Range province. In cross-section, the geometry of the basins within the rift are asymmetrical half - grabens, with major 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 8,700 m below sea level at the bottom of the Albuquerque basin to 3,300 m 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 in origin ). The thickness of the crust increases to the north beneath the rift, where it may be as much as 5 km thicker than it is in the south. The crustal thickness underneath the rift is on average 30 -- 35 km, thinner by 10 -- 15 km than the Colorado Plateau on the west and the Great Plains to the east. The rift is presently nearly tectonically quiescent, but significant deformation and faulting with offsets of many kilometers were responsible for its formation starting about 35 Ma. 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 ( the lithosphere ) stretching like taffy. This extension is associated with very low seismic velocities in the upper mantle above approximately 400 km depth associated with relatively hot mantle and low degrees of partial melting. 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. The sediments that were deposited during rifting are commonly known as the Santa Fe Group. This group contains sandstones, conglomerates, and volcanics. Aeolian deposits are also present in some basins. The Rio Grande Rift is intersected in northern New Mexico by the NE - SW trending Jemez Lineament which extends well into Arizona, defined by aligned volcanic fields and several calderas in the area, including the Valles Caldera National Preserve in the Jemez Mountains. The significance of the Jemez Lineament is unclear ; it is not obviously related to the formation of the Rio Grande rift, but may be a hotspot trail. 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 Valley of Fires, New Mexico and are approximately 5,400 years old. The Socorro, New Mexico region of the central rift hosts an inflating mid-crustal sill - like magma body at a depth of 19 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. Earth and space - based geodetic measurements indicate ongoing surface uplift above the `` Socorro Magma Body ''. Archived from the original on 2010 - 06 - 15. at approximately 2 mm / year. A generalized cross section of the Rio Grande Rift, showing lithospheric and 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 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 ( Moho ) topography ( after Wilson et al. ) ( 2005 ). 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.. Geologic history The Rio Grande rift 's tectonic evolution is fairly complex. The fundamental change in the western margin of the North American plate from one of subduction to a transform boundary occurred during Cenozoic time. The Farallon plate continued to be subducted beneath western North America for at least 100 million years during Late Mesozoic and early Cenozoic time. Compressional and transpressional deformation incurred by the Laramide Orogeny lasted until about 40 Ma in New Mexico. 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 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. 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. Cenozoic extension started about 30 million years ago ( Ma ). There are two phases of extension observed : late Oligocene and middle Miocene. 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 magmatism in mid-Cenozoic time suggests that the lithosphere was hot, the brittle - ductile transition was relatively shallow. There is evidence that the second period of extension began earlier in the central and northern Rio Grande Rift than in the south. It has been suggested that the Colorado Plateau acts as a semi-independent microplate and one way of explaining the creation of the Rio Grande Rift is by the simple rotation of the Colorado Plateau 1 - 1.5 degrees in a clockwise direction relative to the North American craton. See also Caja del Rio Geologic timeline of Western North America Pajarito Plateau Potrillo volcanic field Rio Grande Trail References ^ Jump up to : Chapin, C. ; Cather, S. ( 1994 ). `` Tectonic setting of the axial basins of the northern and central Rio Grande rift. ''. Geological Society of America Special Paper 291. pp. 1 -- 3. ISBN 0 - 8137 - 2291 - 8. ^ Jump up to : Kluth, C. ; Schaftenaar, C. ( 1994 ). `` Depth and geometry of the northern Rio Grande rift in the San Luis basin, south - central Colorado. ''. Geological Society of America Special Paper 291. pp. 27 -- 37. ISBN 0 - 8137 - 2291 - 8. ^ Jump up to : Russell, L. ; Snelson, S. ( 1994 ). `` Structure and tectonics of the Albuquerque basin segment of the Rio Grande Rift : Insights from reflection seismic data. ''. Geological Society of America Special Paper 291. pp. 83 -- 112. ISBN 0 - 8137 - 2291 - 8. ^ Jump up to : Brister, B. ; Gries, R. ( 1994 ). `` Tertiary stratigraphy and development of the Alamosa basin ( northern San Luis basin ), Rio Grande Rift, south - central Colorado ''. Geological Society of America Special Paper 291. pp. 39 -- 58. ISBN 0 - 8137 - 2291 - 8. Jump up ^ Keller, G. Randy ; Baldridge, W. Scot ( 1999 ). `` The Rio Grande Rift : a geological and geophysical overview ''. Rocky Mountain Geology. 34 ( 1 ) : 121 -- 130. doi : 10.2113 / 34.1. 121. Jump up ^ Perry, Frank ; Baldridge, W. ; DePaolo, D. ( August 10, 1987 ). `` 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 of Geophysical Research. 92 # b9 : 9193 -- 9213. Bibcode : 1987JGR... 92.9193 P. doi : 10.1029 / JB092iB09p09193. Jump up ^ `` December Geosphere media highlights ''. ^ Jump up to : Wilson, David ; Aster, Richard ; West, Michael ; Ni, James ; Grand, Steve ; Gao, Wei ; Baldridge, W. Scott ; Semken, Steve ; Pate, Paresh ( 24 February 2005 ). `` Lithospheric structure of the Rio Grande rift ''. Nature. 433 ( 7028 ) : 851 -- 855. Bibcode : 2005Natur. 433... 851W. doi : 10.1038 / nature03297. PMID 15729338. Jump up ^ Fleck, John ( 24 February 2005 ). `` Study Sheds Light on 30 Million Years of Rio Grande Valley Stretching ''. Albuquerque Journal, Electronic Ed. Jump up ^ Hill, Karl ( 25 February 2005 ). `` The Rio Grande Rift : a continent `` stretched like taffy '' ``. NMSU News Release. Jump up ^ Gao, W. ; Grand, S. ; Baldridge, S. ; Wilson, D. ; West, M. ; Ni, J. ; Aster, R. ( 2004 ). `` Upper mantle convection beneath the central Rio Grande rift imaged by P and S wave tomography ''. J. Geophys. Res. 109 ( B3 ) : B03305. Bibcode : 2004JGRB... 10903305G. doi : 10.1029 / 2003JB002743. ^ Jump up to : Baldridge, W. ; Olsen, K. ; Callender, J. ( 1984 ). `` Rio Grande Rift : Problems and Perspectives ''. New Mexico Geological Society Guidebook, 35th field conference. pp. 1 -- 11. Jump up ^ Aber, James S. `` Rio Grande Rift ''. Archived from the original on 29 January 2006. Retrieved 8 February 2006. Jump up ^ Veatch, Steven Wade ( 20 March 1998 ). `` The Rio Grande Rift ''. Archived from the original on 20 December 2005. Retrieved 8 February 2006. Jump up ^ Reid, H.G. ( 1911 ). `` Remarkable earthquakes in central New Mexico in 1906 and 1907 ''. Bull. Seismol. Soc. Am. 1 : 10 -- 16. Jump up ^ Sanford, A.R. ; Balch, R.S. ; Lin, K.W. ( 1995 ). `` A seismic anomaly in the Rio Grande Rift near Socorro, New Mexico ''. 78. Socorro, NM : New Mexico Institute of Mining and Technology Geophysics Open - File Report : 17. Jump up ^ Schlue, J. ; Aster, R. ; Meyer, R. ( 1996 ). `` A lower - crustal extension to a mid-crustal magma body in the Rio Grande Rift, New Mexico ''. J. Geophys. Res. 101 ( B11 ) : 25,283 -- 25,291. Bibcode : 1996JGR... 10125283S. doi : 10.1029 / 96JB02464. Jump up ^ Fialko, Y. ; Simons, M. ( 2001 ). `` Evidence for on - going inflation of the Socorro magma body, New Mexico, from interferometric synthetic aperture radar imaging '' ( PDF ). Geophys. Res. Lett. 28 ( 18 ) : 3549 -- 3552. Bibcode : 2001GeoRL... 28.3549 F. doi : 10.1029 / 2001GL013318. Jump up ^ Morgan, P. ; Golombek, M. ( 1984 ). `` Factors controlling the phases and styles of extension in the northern Rio Grande rift ''. New Mexico Geological Society Guidebook, 35th field conference. pp. 13 -- 20. Jump up ^ Seager, W.R. ; Mack, G.H. ( 1986 ). `` Memoir 41 : Laramide Paleotectonics in southern New Mexico ''. Paleotectonics and Sedimentation in the Rocky Mountain Region : Tulsa, Oklahoma. American Association of Petroleum Geologists : 669 -- 685. Jump up ^ Chapin, C.E. ; Cather, S.M. `` Eocene tectonics and sedimentation in the Colorado Plateau - Rocky Mountain area ''. Arizone Geological Digest. 4 : 173 -- 198. Jump up ^ Karlstrom, K.E. ; Daniel, C.G. ; Taira, Asahiko ( 1993 ). `` Restoration of Laramide right - lateral strike - slip in northern New Mexico by using Proterozoic piercing points ''. Geology. 21 ( 2 ) : 188 -- 211. Bibcode : 1993Geo... 21... 188C. doi : 10.1130 / 0091 - 7613 ( 1993 ) 021 < 0188 : TPUOHH > 2.3.CO ; 2. ^ Jump up to : Morgan, P. ; Sedger, W.R. ; Golombek, M.P. ( 1986 ). `` Cenozoic thermal, mechanical, and tectonic evolution of the Rio Grande rift ''. Journal of Geophysical Research. 91 : 6263 -- 6276. Bibcode : 1986JGR... 91.6263 M. doi : 10.1029 / JB091iB06p06263. Jump up ^ Seager, W.R. ; Shafiqullah, M. ; Hawley, J.W. ; Marvin, R.F. ( 1984 ). `` New K - Ar dates from basalts and the evolution of the southern Rio Grande Rift ''. Geological Society of America Bulletin. 95 : 87 -- 99. doi : 10.1130 / 0016 - 7606 ( 1984 ) 95 < 87 : nkdfba > 2.0.co ; 2. Jump up ^ Steiner, M.B. ( 1988 ). `` Paleomagnetism of the late Pennsylvanian and Permian : A test of the rotation of the Colorado Plateau ''. Journal of Geophysical Research. 93 : 2201 -- 2215. Bibcode : 1988JGR... 93.2201 S. doi : 10.1029 / JB093iB03p02201. Major seismically active faults of North America North America ( crosses national borders ) Alaska - Aleutian megathrust ( US - RU ) Basin and Range Province ( US - MX ) Cascadia subduction zone ( US - CA ) Clarendon - Linden fault system ( US - CA ) Denali Fault ( US - CA ) Northern Cordilleran Volcanic Province ( CA - US ) Puget Sound faults ( US - CA ) Rio Grande rift ( US - MX ) San Andreas Fault ( US - MX ) Southern Great Lakes Seismic Zone ( US - CA ) Tintina Fault ( US - CA ) Canada Charlevoix Seismic Zone Laurentian Slope Seismic Zone Leech River Fault Ottawa - Bonnechere Graben Queen Charlotte Fault Saguenay Graben Saint Lawrence rift system Western Quebec Seismic Zone United States Washington and Oregon Brothers Fault Zone Olympic - Wallowa Lineament Puget Sound ( Seattle Fault, Tacoma Fault ) Walker Lane California Calaveras Fault Garlock Fault Hayward Fault Zone Mendocino Fracture Zone Newport -- Inglewood Fault Puente Hills Fault Rose Canyon Fault San Jacinto Fault Zone ( Elsinore Fault Zone ) Great Basin Independence Valley fault system Moab Fault Teton Fault Wasatch Fault Great Plains Central Oklahoma Fault Zone Humboldt Fault Long Point -- Eureka Heights fault system Nemaha Fault Zone Wilzetta Fault Midwest Marianna Fault New Madrid Seismic Zone Sandwich Fault Zone Wabash Valley Seismic Zone Appalachian Mountains and Atlantic Coast Aiken - Augusta Fault Eastern Tennessee Seismic Zone Middleton Place - Summerville Seismic Zone ( Woodstock Fault ) Northern Appalachians Seismic Zone Ramapo Fault Virginia Seismic Zone Caribbean & Mexico Cayman Trough Chixoy - Polochic Fault Enriquillo -- Plantain Garden fault zone ( Cuba ) Gulf of California Rift Zone Lesser Antilles subduction zone Middle America Trench ( Central America ) Motagua Fault ( Central America ) Pedro Miguel Fault Puerto Rico Trench Retrieved from `` https://en.wikipedia.org/w/index.php?title=Rio_Grande_rift&oldid=852706043 '' Categories : Cenozoic rifts and grabens Rio Grande Basin and Range Province Geologic provinces of Colorado Geology of New Mexico Geology of Texas Geology of Mexico Hidden categories : All articles with dead external links Articles with dead external links from January 2018 Articles with permanently dead external links Wikipedia articles needing clarification from April 2013 All articles with unsourced statements Articles with unsourced statements from April 2013 Colorado articles missing geocoordinate data All articles needing coordinates Talk Contents About Wikipedia Add links This page was last edited on 30 July 2018, at 20 : 34 ( UTC ). 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Question: what is currently happening in the rio grande rift zone
Answer: nearly tectonically quiescent