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Volcanoes of New Mexico

Volcanoes of New Mexico

Winter 2006

VOLCANOES OF

Perhaps more than any other state in one of these enormous eruptions, as are the U.S., New Mexico offers an the striking landforms at City of Rocks enormously diverse record of volcanic State Park. activity. Many familiar and distinctive The shape of volcanoes, and the time New Mexico landscapes are composed that they take to form, vary widely with of volcanoes and volcanic rocks. The the style of eruption. vol- black, barren, lunar landscapes around canoes, such as Capulin Mountain and Grants and Carrizozo are recent Bandera Crater, are perfect cone-shaped flows, and the black flat-topped mesas hills. Cinder cones typically form around Albuquerque are remnants of quickly and are the result of a more-or- older . Mount Taylor and Capulin less continuous single episode of Mountain are volcanoes, and Los eruption. An interesting example is the Alamos is built on the flank of a huge eruption that formed the famous , one so large that it is best Mexican volcano, Paricutín. This vol- viewed from space. Ship Rock is the cano was born in a cornfield on eroded remnant of a volcano, as is February 20, 1943, following several Capulin Mountain in northeastern New Cabezon Peak. Although not as easy to Mexico is a classic cinder cone. The cutaway weeks of local earthquake activity. The recognize, many of the rocks in the view revealing the structure of a typical cinder volcano grew to a height of 150 feet on Gila Mountains and other southern cone (below) shows the layers of ash that its first day of eruption and was 500 and western New Mexico mountain accumulate around the central vent. The feet high 6 days later, reaching a final ranges are also volcanic. The youngest summit crater is often preserved in younger height of over 1,000 feet after 3 features, such as Capulin Mountain, which volcanic rocks in New Mexico are a erupted about 55,000 years ago. Photo © of activity. scant 3,800 years old. At the other end Adriel Heisey. Most volcanoes, however, are larger of the age spectrum, volcanic rocks in and take longer to form. Stratovolcanoes, parts of northern New Mexico are more such as Mount Taylor and Sierra than a billion years old. Blanca, form from repeated eruptions Volcanoes are defined as vents over many thousands of years, and the through which (melted rock) resulting landforms are large, some- and gases erupt from below the ’s times asymmetrical mountains. The surface. Volcanoes range widely in size, in north-central New from small cinder cones, such as duced several hundred cubic miles of Mexico are the geographic expression of Bandera Crater (near Grants), which in single events, hundreds a series of volcanic eruptions that can be climbed in a matter of minutes, of times larger than the May 18, 1980, occurred over the past 15 million years. to much larger landforms like the eruption of Mount St. Helens. The The two largest eruptions, which Jemez Mountains, and skyline-domi- Mogollon–Datil eruptions were larger occurred 1.2 and 1.6 million years ago, nating volcanoes like Mount Taylor and than any volcanic events that have produced the distinctive white-to- 12,000-foot-tall Sierra Blanca on the occurred in historic time, and the salmon-colored cliffs of Bandelier east edge of the Tularosa Basin. deposits from some of these events pro- that form a spectacular backdrop Eruptions from some of the largest duced sheets of rock several hundred around much of the area. These two New Mexico volcanoes, located in the miles across. The well-known very explosive eruptions poured hun- Mogollon–Datil in the “Kneeling Nun” landform near Silver dreds of cubic miles of hot ash, , southwestern part of the state, pro- City is formed from volcanic rock from and gas over the surrounding land-

Published by the New Mexico Bureau of Geology and Mineral Resources • A Division of New Mexico Tech faults. The river flows are probably extinct, meaning that they through a series of broad are unlikely ever to erupt again. valleys created by this However, new volcanoes will certainly stretching process. The form within our state, though probably is a not within our lifetimes. Dr. Allan more subtle crustal Sanford, a geophysicist at New Mexico feature, expressed as an Tech, has identified the Socorro Magma alignment of volcanic Body, a large body of molten rock vents, including (but not underlying the area from Bernardo to limited to) the south of Socorro. Many small earth- Zuni–Bandera, Mount quakes associated with the magma body Taylor, Jemez Mountain, have been detected using seismometers, and Raton–Clayton vol- and some have been felt by local resi- canic fields. This zone dents. These earthquakes are caused by may be the expression of swelling of the , which a weakness formed fractures the overlying brittle rocks. where two very old The magma body is located 12 miles blocks of the earth’s beneath the earth’s surface but shows crust were pressed no signs of erupting soon. The swelling together. In addition to of the magma chamber is being studied various styles of crustal using high-precision global positioning weakness, in system (GPS) data and instruments New Mexico is also likely called tiltmeters. The combination of The major volcanic fields in New Mexico tend to follow two major zones of weakness in the crust and underlying mantle, related to upwelling these two instruments allows even tiny the Jemez lineament and the rift. of abnormally hot changes in the shape of the earth’s mantle material. surface over the magma body to be scape. The rocks were later eroded by detected. This research is being carried water, resulting in the beautiful land- Active, Dormant, or Extinct? out by Los Alamos National Laboratory scape we see today. It is difficult to Volcanoes may be classified as active, geologist Andy Newman, as well as recognize the Jemez Mountains as a dormant, or extinct. An active volcano bureau geologists David Love, Bruce volcanic landform because they are so is one that is emitting lava or volcanic Allen, and Richard Chamberlin. The large. However, on a digital elevation gas. A dormant volcano is not actively magma body’s activity is being closely map (like the one shown on page 3), erupting, but, based on patterns of past monitored by the New Mexico Tech the volcanic shape and large central activity, is likely to erupt again. With geophysics program (on the Web at crater () become evident. the possible exception of the Jemez www.ees.nmt.edu/Geop/NM_Seismolo Volcanism in New Mexico Mountains, all volcanoes in New Mexico gy.html), and any change in activity Volcanic activity occurs in New Mexico and elsewhere in the western United States because of the local nature of the earth’s crust and mantle. The crust in New Mexico is being stretched by regional plate tectonic forces. This stretching produces areas of weakness in the brittle crust, allowing magma to work its way upward. The very large volcanic field represented by the Jemez Mountains occurs at the intersection of two zones of crustal weakness, the and the Jemez lineament. The Rio Grande rift is a major zone of crustal weakness running north to south through New Mexico that formed in order to accommodate stretching of the crust in an east-to- west direction. The surface expression of the Rio Grande rift is a broad, shallow valley caused by down-dropped A complete section of is exposed along NM–4 north of Bandelier National blocks of the crust along rift-bounding Monument.

NEW MEXICO EARTH MATTERS 2 WINTER 2006 outward from the main Ship Rock landform are also part of the original volcano. These walls are actually volcanic dikes, formed when hot magma moved laterally through cracks in the earth’s surface at the time of the eruption, cooled, and solidifed while still in the cracks. Like the central part of the volcano, the dikes are harder than the sedimentary rocks surrounding them and remained standing while the sedimentary rocks weathered away. Similar dikes are found In this oblique digital in many places throughout New elevation model of the Jemez Mountains, the shape of the Valles Mexico, typically appearing as thick, caldera becomes very clear. The Jemez black walls running across the land- River occupies the steep canyon running scape. Some of these dikes can be south from the caldera rim in the fore- traced across the earth’s surface for as ground. Although there have been no major much as 45 miles. would be carefully analyzed to assess eruptions from the Jemez Mountains vol- the possibility of an eruption. canic field in the last million years, there Our Youngest Volcanoes have been a number of smaller eruptions, The large explosive events that In contrast to violent eruptions like formed the upper part of the Bandelier the most recent of which occurred about 60,000 years ago. Bandelier and Ship Rock, most of the Tuff in the Jemez Mountain volcanic recent volcanic activity in New Mexico field occurred in the relatively recent cold ground water. The resulting vio- has been of a more passive eruption geologic past. No eruptions this large lent steam explosions excavated a deep style. This includes the 3,800--old have occurred anywhere in the world in depression in the earth’s surface. McCartys and the 10,000-year-old historic time, and only six have Magma and a variety of rock fragments Bandera Crater lava flows in the occurred in the U.S. in the past 2 and debris fell back into this hole and Zuni–Bandera volcanic field near million years, including two from the were cemented together below the Grants, New Mexico; the 5,400-year- Jemez Mountains, three from earth’s surface. Over the 25 million old Valley of Fire lava flow near Yellowstone, and one from the Bishop years since the Ship Rock eruption Carrizozo; 55,000-year-old Capulin area of . The initial stages of occurred, has removed the Mountain; and 930-year-old Sunset the Bandelier eruption produced ash surrounding rocks, leaving the hard, Crater in nearby . These lava that rained out of the sky over much of cemented throat of the volcano flows and/or cones of volcanic cinders New Mexico. Following this initial “ash exposed. The “walls” that radiate fall,” activity shifted to a “pyroclastic (Continued on page 5) flow” eruption. This stage produced a fast-moving, extremely hot cloud of ash, pumice, and gas that would have destroyed anything in its path, traveling as far as 20 miles from the central vent before solidifying into volcanic rock. The buff-colored cliff-forming rock in which the Bandelier National Monument cliff dwellings are found, and on which Los Alamos is built, was formed by this . The highly explosive Bandelier eruptions are similar to several million-year-old eruptions from Yellowstone that caused ash to fall as far away as New Mexico. Another interesting type of explosive volcanism formed the beautiful land- form known as Ship Rock, or Tse bit’a’i. This landform (illustrated on the masthead of this publication) is a dia- treme, formed when hot magma rising through the earth’s crust encountered This basaltic lava flow near Carrizozo displays a classic ropy (pahoehoe) texture. Note the vegetation that has grown in the 5,200 years since the eruption. NEW MEXICO EARTH MATTERS 3 WINTER 2006 BUREAU NEWS Earth Science including Barbara Fazio, executive Taos training program since 1999. Achievement Awards secretary; Lewis Gillard, GIS technician; Astronauts participated in a series of Mike Smith, database technician; Stacy exercises designed to provide them with The 2006 New Mexico Earth Science Timmons, senior geological research an introduction to techniques for the Achievement Awards were presented on associate; and Patrick Walsh, subsurface geophysical exploration of planets. January 27 of this year to Consuelo fluid geologist. The majestic landscapes of the Taos Bokum, for her tireless work on water area have long provided textbook exam- issues in New Mexico, and to Thomas Award for ples of various geologic landforms, and D. Morrison, chief of the Hydrology Outstanding Publication have served as a backdrop for astronaut Bureau at the New Mexico Office of the At the annual meeting of the Association training exercises since NASA’s Apollo State Engineer, who, for over 25 years, of Earth Science Editors, the New missions in the late 1960s. The current has been at the forefront of shaping Mexico Bureau of Geology and Mineral training program, directed by senior water management policy throughout Resources received the 2005 Award for geologist Paul Bauer with assistance from New Mexico. These awards, co-spon- Outstanding Electronic Publication for U.S. Geological Survey personnel, sored by the New Mexico Bureau of Tectonics, , and volcanism in provided the astronauts with experience Geology and Mineral Resources and the the Southern Rocky Mountains and Rio running gravity and magnetic surveys Energy, Minerals and Natural Resources Grande rift, edited by Steven M. Cather, across buried faults on northern Taos Department in Santa Fe, are presented William C. McIntosh, and Shari A. Pueblo. The data collected during the annually to honor individuals who have Kelley. This award is presented each year exercise will be used in an ongoing made outstanding contributions to to the electronic publication that best bureau program to characterize the advancing or facilitating the role of geo- demonstrates outstanding editing, geology and hydrogeology of the region. science in areas of education, research, design, illustration, writing, effectiveness The current class of astronauts public service, and public policy in New of production cost, and overall effective- included military pilots, school teachers, Mexico. Nominations for next year’s ness in achieving its publication goal. a medical doctor, engineers, and three awards may be submitted (no later than members of the Japanese Aerospace November 1, 2006) to Director Peter Astronauts in Taos Exploration Agency, JAXA. At the end of Scholle at the New Mexico Bureau of During the summer of 2005, bureau the training, NASA officials presented Geology and Mineral Resources. staff provided geologic and geophysical Taos Pueblo leaders with special gold New Staff Members training to eleven NASA astronaut medallions generally given to heads of candidates in the Taos area. This was the foreign states, recognizing the Pueblo as a We’ve welcomed several new staff third class to participate in the bureau’s members to the bureau in the past year, sovereign nation.

Aquifer Mapping Program Albuquerque Basin, Placitas, and the Tackles New Areas of Study Taos Valley, as well as Bruce Allen’s work For the past ten years the bureau staff in the Estancia Basin. Results of a three- has been engaged in hydrogeologic year study in the Española Basin are studies of New Mexico’s aquifers in contributing to a collaborative effort by cooperation with the New Mexico Office Santa Fe County and the City of Santa of the State Engineer and the New Fe to build a regional ground water-flow Mexico Environment Department. model to assist with resource administra- Beginning in the mid-1990s with geo- tion and management. In 2005 a logic mapping and aquifer analysis in the multi-year water-level monitoring study Albuquerque Basin and a hydrogeologic was continued in the Roswell artesian study in Placitas, the bureau has basin. Studies in Arroyo Hondo north of developed an aquifer mapping program Taos and the Peñasco Valley were (AMP) that applies a combination of completed, and new investigations were geologic, geophysical, hydrologic, and initiated in the Sacramento Mountains geochemical information to develop east of Alamogordo, and near Seven descriptive models of ground water flow Rivers in the lower Pecos River valley. in important aquifers around the state. Results of these works are contributing The objective is to provide critically Index map showing completed and ongoing to long-term aquifer monitoring net- needed information on the quality and AMP study areas. works and regional ground water-flow models, supporting water rights adminis- quantity of the state’s ground water. water. Aquifer studies range in scope from Baseline data gathered during the studies tration and local land-use decisions, and short-term local projects to long-term, addressing rural water quality concerns. improve our understanding of the regional studies engaging a variety of geologic framework of aquifers, their disciplines and collaborators. With support —Peggy Johnson hydrologic characteristics, water levels in from the 2005 state legislature in the form the aquifers and how they change over Peggy is a senior hydrogeologist of a $300,000 one-year appropriation, the with the New Mexico Bureau of time, and the presence of natural con- program has been able to complete some taminants (such as arsenic and uranium) Geology and Mineral Resources and studies while continuing or starting others. manages the Aquifer Mapping Program. that affect the potability of ground Past efforts include studies in the

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A Word About Dates Mexico have been analyzed in this One important part of understanding laboratory, and these data have greatly volcanic processes involves knowing the improved our understanding of the chronology, or timing, of volcanic eruption history of New Mexico volca- activity. The ways in which volcanic noes. The 40Ar/39Ar technique involves chronology is determined have evolved measuring the ratio of parent to and improved dramatically over the daughter isotopes and is useful for vol- past 50 years. The main techniques canic rocks of a wide range of ages. that have contributed to a better Other techniques that have been understanding of volcanic chronology employed in determining the ages of rely on isotopic measurements. volcanic sequences in New Mexico Currently, much of this work is carried include the 14C, 36Cl, and 3He tech- out in the argon radioisotope laborato- niques. Many of the ages reported in Volume 6, Number 1 ry at the New Mexico Bureau of this article have been determined only Published twice annually by the NEW MEXICO BUREAU OF GEOLOGY Geology and Mineral Resources, on the in the past 10 years and, in many AND MINERAL RESOURCES campus of New Mexico Tech. cases, represent substantial changes Peter A. Scholle Thousands of volcanic rocks from New from earlier age estimates. Director and State Geologist a division of NEW MEXICO INSTITUTE OF (Continued from page 3) 1,000 years. She estimates that about MINING AND TECHNOLOGY are formed by the types of eruptions 100 eruptions will occur in the next Daniel H. López million years. Widespread seismic President that are witnessed today by so many 801 Leroy Place tourists in Hawaii. Based on past pat- monitoring around the state would Socorro, New Mexico 87801-4796 terns of activity, if a volcanic eruption help provide forewarning and predict (505) 835-5420 were to occur in New Mexico in the where an eruptive event might take Albuquerque Office place. Living in New Mexico, we are 2808 Central SE Albuquerque next 100 or 1,000 years, it would most New Mexico 87106 likely form either a lava flow, a cinder lucky to be in a place where volcanoes (505) 366-2530 cone, or both. The eruptions that form form many dramatic and beautiful Visit our main Web site such features do not include major landforms. At the same time, we are geoinfo.nmt.edu explosive activity; rather they involve living in a place with a small but very Board of Regents low levels of explosivity that form cin- real chance of volcanic activity in the Ex Officio Bill Richardson der cones and slow-moving, very hot next century. Governor of New Mexico lava that flows downhill from the vent —Nelia W. Dunbar Veronica C. Garcia of the volcano. This type of eruption Secretary of Education would be unlikely to cause major loss Nelia is a geochemist and the assistant Appointed of life or property, although the initial director in charge of laboratories for the Jerry A. Armijo President stages of the eruption could be New Mexico Bureau of Geology and 2003–2009, Socorro dangerous to any nearby onlookers. Mineral Resources. Her research on Richard N. Carpenter How likely is an eruption to occur in volcanoes has taken her throughout the Secretary/Treasurer New Mexico in the near future? A state, as well as far from New Mexico, 2003–2009, Sante Fe New Mexico Tech graduate student, most recently to Mount Erebus in Ann Murphy Daily 2005–2011, Santa Fe Ellen Limburgh, attempted to make Antarctica. Sidney M. Gutierrez some estimates. She studied the distri- 2001–2007, Albuquerque bution and age of many of the known Michaella J. Gorospe volcanoes in New Mexico. She found 2005–2007, Socorro that there have been more than 700 Editors volcanic eruptions in New Mexico in L. Greer Price the last 5 million years, with eruptive Jane C. Love styles ranging from dangerously Layout Thomas Kaus explosive to passive. Volcanoes in New Graphics Mexico that have been active in the last Thomas Kaus 5 million years fall into 11 different Leo Gabaldon geographic areas, or volcanic fields. Brigitte Felix Kludt Kathryn Glesener Limburgh estimated that there is Glen Jones roughly a 1 percent chance that some Earth Matters is a free publication. For type of volcanic eruption will occur subscription information please call (505) 835-5490, or e-mail us at somewhere in New Mexico in the next [email protected] 100 years, and a 10 percent chance Cover photo of Ship Rock, New Mexico that an eruption will occur in the next © Gary Rasmussen

NEW MEXICO EARTH MATTERS 5 WINTER 2006

NEW PUBLICATIONS Geologic Map 74— Geologic Highway Caballo and Apache Gap quad- Map, compiled by Maureen E. rangles, Sierra County, New Wilks, 2005. Published jointly by Mexico, by W. R. Seager and G. the New Mexico Geological Society H. Mack, 2005, 2 sheets, scale and New Mexico Bureau of 1:24,000, 6 cross sections. ISBN Geology and Mineral Resources, 1 1-883905-23-0. The map and folded sheet containing text and cross sections are in PDF format. figures, scale 1:1,000,000, ISBN 1- A georeferenced TIFF image is 585460-22-2. $10.00 plus $2.50 also provided on the CD. No GIS shipping and handling and 5% data are available for these quadrangles at this time. Available gross receipts tax for New Mexico on CD-ROM only. $15.00 plus $2.50 for shipping and han- residents. dling and 5% gross receipts tax for New Mexico residents. In addition to the geologic highway The Caballo and Apache Gap quadrangles span an area from the map (1:1,000,000), the single sheet includes full unit descrip- and eastern piedmont slopes of the central tions, cross sections, regional stratigraphic columns, photos, and Caballo Mountains westward across the Caballo Reservoir and additional text material and maps on the geology of New I–25 into basin-fill and piedmont-slope deposits of the Mexico. First published in 1982, this new edition has been . Fifty-nine map units range in age from completely revised and updated to include a map legend, two metamorphic and plutonic rocks to alluvial resource maps, one on energy, and the other on metals and and fluvial deposits. industrial minerals in New Mexico. The new Landsat image This map is part of a larger study of the Caballo Mountains was compiled between 1989 and 1993. that includes providing complete map coverage at a scale of 1:24,000; six maps have been published to date. As a supplement to the quadrangle maps, Memoir 49, Geology of the Caballo Mountains, New Mexico, was released by the New Mexico Bureau of Geology and Mineral Resources in 2003.

For more information about these and other bureau publications: Visit our Web site at geoinfo.nmt.edu; write or visit our Publications Office on the campus of New Mexico Tech, 801 Leroy Place, Socorro, New Mexico 87801; call (505) 835-5490, or e-mail us at [email protected]. Payment (check or money order payable to NMBGMR) must be enclosed with mailed orders. Telephone orders may be paid with VISA, Discover, American Express, or MasterCard.

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NEW MEXICO EARTH MATTERS 6 WINTER 2006

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