WINTER 2021

New ’s Volcanic Hazards: A Matter of Time ew Mexico’s world-renowned land- one side of the fault moves upward, forming (known as calderas to volcanologists, because Nscapes reflect the vigorous geologic mountains, while the other side of the fault of their resemblance to large caldrons) activity of the region. For those who live moves downward, producing a basin. The erupted in southwestern New Mexico, each here, we see—and sometimes even feel—this Sandia Mountains and the Albuquerque of which injected dozens to hundreds of Earth energy. However, such geologic vigor basin are a textbook example of this process. cubic miles of ash into the atmosphere, and comes with a price in the form of geologic Recent volcanism in New Mexico can be spilled hot, incandescent ash-flows across hazards. Reports on the evening news about divided into two broad periods of activ- the landscape. Before and after the colossal earthquakes in eastern New Mexico are ity, each with their own distinctive traits. supereruptions, numerous “small” volcanoes increasingly common. Driving over moun- Between about 37 and 25 million years ago, erupted, producing explosions similar to tain passes and through deep gorges of a cluster of about twenty supervolcanoes the famous May 18, 1980 eruption of Mt. northern New Mexico may require dodging boulders on the road—evidence of recent Maps and photographs A) Basaltic lava flows, rock falls and landslides. Floods from the showing the two different B such as the 5,200-year-old summer monsoons frequently reshape our styles of recent eruptions flow near Carrizozo (the neighborhood arroyos, and redesign in New Mexico. second youngest eruption in New Mexico), are the rapids in our rivers. One of the A greatest potential hazards in New Mex- 380 common. The lava flowed 45 miles south down the Mexico, one not experienced by . B) Young any humans in recent history, is a flows, such as in Valley of volcanic eruption from the many Carizzozo Fires State Park, typically young volcanic fields found in the have very little vegetation state. In this article, we explore and a well-preserved 54 the history of young volcanoes in flow surface. New Mexico, describe recent n

research to better understand these a

hazards, and ponder the likely a

events during a future eruption. 0 2 miles a D

0 2 kilometers A Brief History of New Mexico Volcanism Pick nearly any place in New Mexico and C you are likely to find some evidence for past volcanic activity. Most volcanism in the ek state has occurred in just the last 35 million re C o i years. This is when the rift, a n Valles o

t

n

continental-scale feature related to extension A

caldera

n a of the crust, began to form. Rifting triggered S Los Alamos C) Young, explosive rhyolitic eruptions two major geologic processes, volcanism and in New Mexico are rare and are found only faulting. Extension causes Earth’s crust to 501 in the Jemez Mountains. D) Ash-rich deposits Jem are common during rhyolitic eruptions. thin, allowing the molten mantle to either ez Riv er 4 This outcrop, along NM 4, exposes a rise toward the surface, or to melt overlying 4 0 2 miles 40-foot sequence of ash ejected during rocks, both of which can produce volcanic a 74,000-year-old eruption. Photo by 0 2 kilometers eruptions. During faulting, the crust on Nick Meszaros.

Published by the New Mexico Bureau of Geology and Mineral Resources • A Research Division of New Mexico Tech Laser This younger pulse of activity is clustered (heats samples) into eight major volcanic fields and a few iso- Extraction line lated vents and related flows. Some of these (cleans sample gas) volcanic fields are located in the Rio Grande rift. Others are located along a feature called the Jemez lineament, a zone of crustal weakness that has focused volcanic activity along a northeast-trending line. Although most eruptions in New Mexico in the last 10 million years are small, the Valles caldera, Mass spectrometer also known as “New Mexico’s supervolcano,” (measures argon isotopes) produced two immense, explosive eruptions at 1.6 and 1.2 million years ago, generating Photo of students working in the New Mexico Geochronology Research Laboratory. The lab has widespread ash falls. supported hundreds of projects from around the world, many led by New Mexico Tech students. Why did the style of eruptions shift between the older and younger volcanoes? St. Helens. Thankfully, this field of New lava with very little ash. Some examples of Geologists have determined that the shift was Mexico’s supervolcanoes is now extinct, and these small volcanoes include cinder cones related to a change in the composition of the is beautifully exposed in the Gila Mountains (steep-sided cones built from the accumula- magma. The older calderas typically erupted and surrounding areas. tion of small, cooled fragments of lava called rhyolite composition magma, which contains Beginning about 12 million years ago cinders), shield volcanoes (volcanoes with large amounts of silica, making the magmas and continuing until about 3,900 years ago, very shallow slopes formed by many lava more viscous (less likely to flow). When mag- the style of volcanic activity in New Mexico flows), fissure vents (lines of small volcanoes mas rise through the crust, the decrease in dramatically changed. Instead of the cataclys- that erupt along a fracture), and maar craters pressure allows dissolved gases to be released. mic, caldera-forming eruptions, the younger (formed when rising magma meets ground- However, the viscous rhyolite prevents gas volcanoes produced smaller eruptions of water, causing a violent steam explosion). expansion, and causes pressure to build,

Valles caldera Brazos Cones Taos Plateau Ocate magma body ?–179,000 yrs, 4 vents ~6.0–1.0 m.y., 50 vents 8.3 m.y.–810,000 yrs, 50 vents unknown frequency 1 per 100,000 yrs 1 per 150,000 yrs Jemez Mountains no <500,000 yr old eruptions no <500,000 yr old eruptions 16.5 m.y.–68,000 yrs, 400–450 vents 109o 103o 1 per ~39,000 years 37o

only two eruptions <500,000 yrs at 74,000 and 68,000 yrs TAOS Raton-Clayton Mt. Taylor and Mesa Chivato 9.2 m.y.–37,000 yrs, 140 vents 4.5–1.3 m.y., >100 vents 1 per 65,000 yrs ~1 per 32,000 yrs 368,000–37,000 yrs, 9 vents no <500,000 yr old eruptions 1 per 37,000 yrs SANTA FE

Zuni-Bandera Albuquerque Volcanoes ? to 3,900 yrs, 80–90 vents JEMEZ LINEAMENT 1 fissure eruption at 195,000 yrs GRANTS ALBUQUERQUE unknown frequency 380,000–3,900 yrs, 38 vents Cat Hills 1 per 10,000 yrs 268,000–116,000 yrs, 3 fissure eruptions 1 per 50,000 yrs Red Hill-Quemado 8 m.y.–25,000 yrs, 40 vents SOCORRO Valley of Fire 1 per 200,000 yrs 347,000–5,200 yrs, 4 vents T F I R E D N A R G O I R 120,000–25,000 yrs, 7 vents 1 per 85,000 yrs 1 per 14,000 yrs Jornada del Muerto Lucero 817,000–78,000 yrs, 2 vents 8.3 m.y.–192,000 yrs, 25 vents only 1 <500,000 yr old eruption 1 per 324,000 yrs 1 <500,000 yr old eruption Potrillo 916,000–16,000 yrs, 111 vents Socorro magma body 0 50 mi N 1 per 8,000 yrs LAS CRUCES 327,000–16,000 yrs, 14 vents Animas 0 50 km 1 per 22,000 yrs 1 eruption at 349,000 yrs 32o

Map showing locations and eruption Active magma bodies Name of volcanic field frequencies of late Cenozoic (less than Age range, number of eruptions and 10 million years old) volcanic activity Late Cenozoic volcanic rocks average eruption frequency for the entire history of field in New Mexico. Vents are clustered into (10 m.y. to present) Age range, number of eruptions and eight major volcanic fields and numerous Vent migration direction (if applicable) average eruption frequency for eruptions in the last 500,000 yrs isolated vents and flows.

NEW MEXICO EARTH MATTERS 2 WINTER 2021 resulting in a highly explosive eruption. The a key element in understanding this threat by heating with a laser at progressively higher rapid release of pressure during the eruption was missing until recently. To answer any of temperatures to remove more and more gas. causes bubbles to quickly expand and burst, the three questions we must know the precise The extracted gases are then cleaned so that fracturing the rapidly solidified magma into ages and locations of past eruptions. Although only argon is delivered to the mass spectrome- small fragments called ash. However, most of many studies have investigated aspects of ter (an instrument that measures the abun- the younger volcanoes in New Mexico (Valles eruptive behavior in the state, no study dances of isotopes) for the age determination. caldera is the exception) erupted basalt, a existed that addressed state-wide eruptive time A major upgrade to the lab in 2011 improved type of magma that is low in silica and rich in patterns. This data gap began to close in 2013, our precision for dating young volcanic rocks iron and magnesium. These types of magmas when researchers at the New Mexico Bureau of to less than a few thousand years, allowing have low viscosity (more likely to flow). The Geology and Mineral Resources (NMBGMR) volcanologists to detect patterns in eruptive gases in the rising basaltic magmas can easily at New Mexico Tech were awarded a National activity that were previously unresolvable. escape, preventing the extreme build-up of pressure, and thus typically producing lava Summary of New Mexico volcanic eruptions in the last 100,000 years Eruption Frequency flows with only mild explosive activity. With the new ages, # of Eruptions eruption frequency is Will There be Future Volcanic 2 4 6 8 10 12 14 now better known for Activity in New Mexico? Zuni–Bandera (44% of total) all the volcanic fields Raton–Clayton (19% of total) in New Mexico. As Although there hasn’t been an eruption in Potrillo (16% of total) expected, the frequency New Mexico in almost 4,000 years, there are Red Hill–Quemado (9% of total) of activity differs three lines of evidence that suggest future Jemez Mountains (6% of total) among volcanic fields volcanic activity is likely. Jornada del Muerto (3% of total) and varies throughout Average of Valley of Fires (3% of total) the lifespan of each 1) Two places in New Mexico are underlain 1 eruption per individual field. For by relatively shallow magma that could 2,000 years erupt. The Socorro magma body exists example, the most rapid at a depth of about 12 miles. The other eruption frequency is located beneath the Valles caldera at is found in the Average of depths of 3 to 9 miles. Zuni–Bandera volcanic 1 eruption per field, located just 2) Thousands of volcanoes have erupted 3,400 years during the last 10 million years, including south of Grants, where 700+ in the last 5 million years, and 350 the average eruption frequency is about one

in the last 2 million years. 0 Years

3) There have been at least four eruptions in before eruption every 3,800

10,000 30,000 20,000 50,000 70,000 90,000 40,000 60,000 80,000

the last 11,000 years, suggesting the long present 100,000 years during the last 65,000 years, and one episode of activity that began 10 million Graphical summary of eruptions in the last 100,000 years in years ago is not over. New Mexico. Symbols represent the age of a dated volcanic rock, event every 14,000 years These aspects of New Mexico volcanism coded to their respective volcanic fields (upper left). between 350,000 and suggest that future activity is not a question 100,000 years ago. This of if, but when! suggests that eruptive Science Foundation (NSF) grant to study activity has increased during the field’s lifespan. Understanding Past Volcanism volcanic hazards. Since then, nearly 200 new In contrast, other fields show a decrease in to Prepare for Future Volcanism ages from almost 100 volcanic deposits have activity. In the Potrillo field, near Las Cruces, been generated for eruptions that took place in an estimated 100 vents erupted between One of the fundamental components in haz- the last 500,000 years. 916,000 and 262,000 years ago, an eruption ards assessment is establishing the ages and Before revealing the results of our study, frequency of one per 6,500 years. However, locations of past events. For volcanic hazards, let’s discuss how the ages of volcanic rocks are between 190,000 and 21,000 years ago, only this means answering three questions. determined. The NMBGMR is home to the 10 volcanoes erupted for a frequency of one 1) What is the eruption frequency, and is it New Mexico Geochronology Research Labora- event per 16,900 years, a rate that is 2.5 times increasing or decreasing? tory, a world-renowned facility that specializes slower than the earlier history of the field. 2) How much time passed between erup- in a rock-dating technique called 40Ar/39Ar Another way to characterize volcanic tions (known as the repose period)? dating. The method relies on the radioactive activity is to calculate eruption frequency 3) Are the vents randomly dispersed, or have decay of isotopes of potassium to isotopes of for the entire state. One challenge is that the they migrated through time? argon. The technique is particularly useful for geologic evidence of older volcanic eruptions The first two questions help address the over- dating volcanic rocks for two reasons. First, is commonly lost to erosion or covered by all threat of a volcanic field. For example, a potassium is the eighth most abundant ele- younger lava flows, thus skewing the calcula- field that erupts once every 1,000 years poses ment in Earth’s crust and thus exists in nearly tions. Therefore, the most recent activity pro- a much greater threat than a field that erupts every volcanic rock. Second, the half-life (the vides the best information to use for our cal- once every 100,000 years. The third question amount of time it takes for half of the potas- culations. Between 100,000 and 3,900 years helps volcanologists assess where to expect sium to decay to argon) is about 1.25 billion ago, there were 32 eruptions in New Mexico, future activity. years, and so is useful for dating rocks in all of for an average frequency of one eruption per Despite the recognition that New Mexico Earth’s 4.56-billion-year history. In the lab, the 3,000 years. Although the average frequency is susceptible to future volcanic eruptions, isotopes of argon are released from the sample (3,000 years) is less than the amount of time

NEW MEXICO EARTH MATTERS 3 WINTER 2021 since the last eruption (3,900 years), this does mature vegetation, whereas younger parts of what hazards to expect based on past volca- not indicate that New Mexico is “due” for an the field lack vegetation because plants have nism in the state and around the world. eruption. Instead, it means that the current not had time to grow on the youngest flows. period of inactivity is typical for New Mexico The important implication to the vent migra- A Small Basaltic Eruption volcanism and we should consider the region tion pattern is that future volcanic activity The most common type of volcanism in to be dormant, rather than extinct. within each of the volcanic fields may be New Mexico during the last 500,000 years located near the most recent eruptive sites or are small basaltic eruptions that produce Eruption Repose Periods perhaps just east. This vent migration pattern cinder cones and lava flows. These eruptions Further complicating the ability to predict should only be used as a guide, not a rule, for typically start with mild, gas-rich explosions future volcanism is the erratic timing between assessing future activity, as there are plenty of that produce some ash and cinders (small eruptions. There is evidence that consecutive exceptions to the pattern. fragments of cooled lava). Ash-rich eruptive eruptions can happen rapidly. For example, There are two other interesting aspects to columns can range from a few hundred feet a repose period of approximately 1,000 years the newly discovered vent migration patterns to more than a mile high, possibly impact- separates the two youngest eruptions in the in New Mexico. First, other volcanic fields in ing air traffic and downwind airports. Finer state. Alternatively, there are long, inactive the southwest, such as the San Francisco and ejected material would be carried downwind periods of tens of thousands of years, both Springerville volcanic fields in neighboring and could accumulate to many feet thick within individual fields and across the entire Arizona, show similar eastward vent migra- near the volcano and perhaps a few inches state. For example, between 400,000 and tion. Second, in all of these fields, the eastern thick miles away. If ash and cinders accu- 300,000 years ago, only three eruptions have migration rate is a few inches per year, which mulates on homes and other infrastructure, been discovered. The inconsistent repose is a similar rate, but opposite, to the south- it may collapse roofs and power lines. The period between volcanic eruptions makes pre- western movement of the North American gases released in these types of eruptions are dicting future activity impossible. Plate. This suggests that the migration of typically rich in sulfur dioxide, which can kill volcanism in the Southwest is, in part, related vegetation and cause respiratory problems Vent Migration Patterns to movement of tectonic plates. for people and animals. As the gas-rich phase By combining the new ages with the of the eruption wanes, a lava flow might locations of volcanoes, we can examine emanate from the cone. Basalt flows can how activity in New Mexico migrates, What Would a Future Eruption travel many miles downslope, so downhill geographically, through time. In general, Look Like? communities would likely need to evacuate. the locations of most volcanic vents have Likewise, infrastructure might be at risk. migrated eastward. That is, older vents are Although the new ages and spatial analyses During the 2018 lower Puna eruption in found on the western parts of the fields and allow us to understand past volcanic erup- Hawaii, lava flows travelled through Leilani the youngest vents are located to the east. tions, they do not allow us to predict when or Estates, forcing evacuations and causing an For example, in the Zuni-Bandera field, the where the next volcano will appear. Instead, estimated $800 million in damage. Most of older volcanoes in the southwestern part of a useful exercise is to envision what a future the basaltic volcanoes in New Mexico are in the field are covered by windblown dust and eruption in New Mexico might look like, and rural areas where damage due to lava flows

40

117

53

Flows older than 100,000 years Flows younger than

0 5 miles 20,000 years ent migration direction 0 5 kilometers V

Example of vent migration in the Zuni-Bandera volcanic field. Older flows and vents in the southwestern part of the field (upper left photo) are more eroded and have more vegetation. In contrast, younger flows and vents to the east and northeast (lower right photo) have little erosion and less vegetation. Photos from Kelsey McNamara.

NEW MEXICO EARTH MATTERS 4 WINTER 2021 Examples of eruptions that resemble past and would be minimal, but the ash deposits could potentially future volcanism in New Mexico. impact local communities. Based on historical events, this type of eruption could last a few A weeks to many years, potentially posing both short-term and long-term hazards.

A Larger Rhyolitic Eruption The only location in New Mexico to experience explosive rhyolitic eruptions in the last million years is the Jemez Mountains, and any future eruptions there would likely follow the same trend. Such eruptions produce much more ash than their basaltic cousins, thus a far larger part B of the state and southwestern U.S. air space would be affected. For example, ash from a Volume 21, Number 1 74,000-year-old Valles caldera eruption is found Published twice annually by the 125 miles south in Socorro. Some of our largest NEW MEXICO BUREAU OF GEOLOGY cities, such as Albuquerque, Santa Fe, and Taos AND MINERAL RESOURCES are near Valles caldera, and could be at risk. A Research Division of Pyroclastic flows (a dense mixture of ash and NEW MEXICO INSTITUTE OF MINING AND TECHNOLOGY hot gases that travels downslope at rapid speeds) and ash falls could decimate the dozens of Dr. Stephen G. Wells communities that occupy the valleys surround- President, New Mexico Tech ing the caldera. In contrast to basaltic eruptions, Dr. Nelia Dunbar A and B) Photos of the 2018 lower Puna the viscous rhyolitic flows do not typically State Geologist and Director, Hawaii eruption. This four-month long travel far from the vent and are likely not major New Mexico Bureau of Geology eruption produced many small cones and hazards. Fortunately, eruptions at Valles caldera and Mineral Resources extensive lava flows that consumed homes, are infrequent (2 in the last 100,000 years), and roads, and infrastructure. Most recent activity 801 Leroy Place recent dating suggests increasing repose periods Socorro, New Mexico 87801-4750 at Zuni-Bandera and near Carrizozo in New Mexico resembles this type of eruption. between eruptions. 1015 Tijeras Avenue NW, Suite 200 Albuquerque, New Mexico 87106 Summary (505) 366-2530 C Although there is no indication that New BOARD OF REGENTS, EX OFFICIO Mexico will experience an eruption any time in Michelle Lujan Grisham the near future, volcanic activity in our state is Governor of New Mexico certainly not over. Periods of inactivity of sev- Carmen Lopez eral thousands of years, such as the one we are Secretary of Higher Education in now, are common, having happened many Appointed times in recent geologic history. Nevertheless, Deborah Peacock volcanic eruptions pose a real and perhaps President, 2017–2022, Corrales underappreciated threat to New Mexicans. Hence, geologists remain vigilant to quickly Jerry A. Armijo Secretary-Treasurer, 2015–2020, Socorro identify any signs of a volcanic awakening, such as increased seismicity due to moving magma, Dr. Yolanda Jones King D changes to gas emissions, changes to hot and 2019–2024, Socorro cold springs, changes to geothermal features David Gonzales above magma chambers, and ground uplift that 2015–2020, Farmington might indicate magma moving closer to the Veronica Espinoza, Student Member surface. Additional studies to understand past 2019–2020, Socorro eruptions are underway and will help Editor us prepare for an eruption scenario in the Dr. Paul Bauer future, when volcanic activity returns to The Layout and production, Land of Enchantment. Belinda Harrison -Matthew Zimmerer Graphics Photo of the June 12, 1991 eruption of C) Matthew Zimmerer is a field geologist with the Brigitte Felix and Stephanie Chavez Mt. Pinatubo in the Philippines. Future rhyo- Visit our website at: geoinfo.nmt.edu litic volcanism in the Jemez Mountains may New Mexico Bureau of Geology and Mineral Resources. His research focuses on volcanism in the produce a similar highly explosive, ash-rich New Mexico Earth Matters is a free publication. eruption. D) Photograph showing buildings southwestern U.S. and . For subscription information, please call that collapsed on the Clark Air Force base This work was made possible by an NSF grant (575) 835-5490 or e-mail us at due to the weight of ash from the cataclysmic and support from Matt Heizler, Bill McIntosh, Jake [email protected] eruption of Mt. Pinatubo on June 15, 1991. Ross, Lisa Peters, and students at the New Mexico Cover photo of Kasha-Katuwe Tent Rocks All photos courtesy of the United States Geochronology Research Laboratory. Paul Bauer, Geologic Survey. National Monument, New Mexico Fraser Goff, and Nelia Dunbar provided reviews. © Adam Read

NEW MEXICO EARTH MATTERS WINTER 2021 New Mexico Bureau of Geology & Mineral Resources

New Mexico Institute of Mining & Technology NONPROFIT ORGANIZATION 801 Leroy Place U.S. Postage Socorro, NM 87801-4750 Return service requested PAID permit no. 1100 albuquerque, nm

Bureau News State Water Data Initiative Online project’s experiments will focus on how slight The 135-mile Rio Chama of northern New differences in molecular properties such as Mexico is a major tributary of the Rio The NM Water Data Initiative was estab- ionic radius, ion size, and ionic charge affect Grande. From its alpine headwaters at the lished by the state legislature in 2019. This the behavior of REE in aqueous fluids. The Continental Divide of the glaciated San collaborative initiative will make statewide investigators will create a database, called the Juan Mountains in southern Colorado, water data accessible, openly shared, and MINES thermodynamic database, which this hidden gem flows across the Colorado interoperable. The expanding data catalog researchers can use to model the behavior of Plateau in a spectacular canyon cut into and gallery of maps are found at newmexi- REE in hydrothermal systems. Mesozoic sedimentary rocks, in places up to cowaterdata.org. 1,500 feet deep. Towering, vibrant, sandstone cliffs, heavily wooded side canyons, superb Research Group Lands Major DOE Grant Upcoming Publication camping, and a diversity of historical sites offer an outstanding wild river backdrop for Bureau of Geology and NM Tech Economic The Rio Chama: A River Guide to the the boater, angler, hiker, or camper. Geologist Dr. Alexander Gysi was granted Geology and Landscapes This book contains detailed river maps $895,603 from the U.S. Department of of the seven sections of the Rio Chama, plus Energy to study fundamental chemical its three resplendent reservoirs, from the properties of rare earth elements (REE) in Colorado headwaters to its confluence with hydrothermal fluids using lab experiments the Rio Grande near Española. The Chama and numerical modeling. The project will Canyon section, below El Vado Dam and support two NM Tech Ph.D. students and through the Chama Canyon Wilderness, is two post-doctoral researchers. one of the finest, multi-day, whitewater trips Rare earth elements are critical metals in the Southwest. The Rio Chama will be that are essential components of high-tech printed in early 2021. and green-tech devices, such as smart phones, efficient lights, and permanent magnets used in wind turbines and hybrid cars. REE For information about the bureau exist in only trace amounts in Earth’s crust, and our publications: but can be concentrated in ore deposits by Visit our website at geoinfo.nmt.edu hydrothermal processes. However, the energy (575) 835-5490 processes involved in the formation of these [email protected] deposits are poorly understood, so thermody- or visit the Bureau of Geology bookstore on namic modeling can predict REE mobility in the campus of New Mexico Tech fluids, and can help explain field observations 801 Leroy Place, Socorro, NM 87801 and mineral assemblages of ore deposits. The

NEW MEXICO EARTH MATTERS WINTER 2021