In 2013, two small fragments of the Tissint Martian meteorite were "planted" in Arizona's Sonoran Desert in order to deliberately expose them to terrestrial desert weathering. The first piece was recovered for analysis after 12 months of exposure, and the remaining fragment in 2016 (read about Tissint's recovery from the Arizona desert here). During their time in the Sonoran Desert, the meteorite fragments were exposed to hot summer temperatures (as high as 48C or 118F) and occasional bouts of monsoon rain.
The final fragment of the Tissint Martian meteorite (M&M for scale) was recovered after 36 months in the desert. Photos: ASU/CMS.
Upon their return to ASU's Center for Meteorite Studies, the meteorite pieces' volatile (such as water) and isotopic compositions were the subjects of in-depth analyses. The results of this work, led by Center alumna Dr. Alice Stephant were recently published in the Nature journal Scientific Reports.
Scientists believe the solar system was formed some 4.6 billion years ago when a cloud of gas and dust collapsed under gravity, possibly triggered by a cataclysmic explosion from a nearby massive star or supernova. As this cloud collapsed, it formed a spinning disk with the sun in the center.
Piece by piece, scientists have been working on establishing the formation of the solar system with clues from space. Now, new research has enabled scientists Meenakshi Wadhwa and Daniel Dunlap at Arizona State University’s Center for Meteorite Studies in the School of Earth and Space Exploration, as well as researchers from the University of New Mexico and NASA’s Johnson Space Center to add another piece to that puzzle, with the discovery of the oldest-ever dated igneous meteorite.
“The meteorite we studied is unlike any other known meteorite,” co-author Dunlap said. “It has the highest abundance of silica and the most ancient age (4.565 billion years old) of any known igneous meteorite. Meteorites like this were the precursors to planet formation and represent a critical step in the evolution of rocky bodies in our solar system.”
The research on this meteorite, published today in Nature Communications, provides direct evidence that chemically evolved, silica-rich crustal rocks were forming on planetesimals within the first 10 million years prior to the assembly of the terrestrial planets and helps scientists further understand the complexities of planet formation.
A meteorite laced with green crystals
The research began at the University of New Mexico (UNM) with a yet-to-be studied meteorite, called “Northwest Africa (NWA) 11119,” that was found in a sand dune in Mauritania. The rock is lighter in color than most meteorites and is laced with green crystals, cavities and quench melt, a type of rock texture that suggests rapid cooling and is often found in volcanic rocks which cool rapidly or “quench” when brought to the surface quickly.
Using an electron microprobe and a computed tomography (CT) scan at UNM and NASA’s Johnson Space Center facilities, lead author Poorna Srinivasan started to examine the composition and mineralogy of the rock. Srinivasan noted the intricacies of NWA 11119 including its unusual light-green fusion crust.
“The mineralogy of this rock is a very, very different from anything that we've worked on before,” Srinivasan said. “I examined the mineralogy to understand all of the phases that comprise the meteorite. One of the main things we saw first were the large silica crystals of tridymite which is similar to the mineral quartz. When we conducted further image analyses to quantify the tridymite, we found that the amount present was a staggering 30 percent of the total meteorite — this amount is unheard of in meteorites and is only found at these levels in certain volcanic rocks from the Earth.”
Video courtesy of the University of New Mexico.
Determining the age and origin of the meteorite
At ASU’s Center for Meteorite Studies, scientists and co-authors Dunlap and Wadhwa used inductively coupled plasma mass spectrometry in their Isotope Cosmochemistry and Geochronology Laboratory, which helped determine the precise formation age of the meteorite. The research confirmed that NWA 11119 is the oldest-ever igneous meteorite recorded at 4.565 billion years old.
“The purpose of this research was to understand the origin and formation time of an unusually silica-rich igneous meteorite,” said Wadhwa, who is the director of ASU’s Center for Meteorite Studies. “Most other known igneous asteroidal meteorites have ‘basaltic’ compositions that have much lower abundances of silica — so we wanted to understand how and when this unique silica-rich meteorite formed in the crust of an asteroidal body in the early solar system.”
In addition, the research involved trying to figure out through chemical and isotopic analyses what body the meteorite could be from. Utilizing oxygen isotopes done in collaboration with co-author Karen Ziegler of UNM’s Center for Stable Isotope lab, the team was able to determine that it was definitely extraterrestrial.
“Based on oxygen isotopes, we know it's from an extraterrestrial source somewhere in the solar system, but we can't actually pinpoint it to a known body that has been viewed with a telescope,” Srinivasan said. “However, through the measured isotopic values, we were able to possibly link it to two other unusual meteorites (Northwest Africa 7235 and Almahata Sitta) suggesting that they all are from the same parent body — perhaps a large, geologically complex body that formed in the early solar system.”
One possibility is that this parent body was disrupted through a collision with another asteroid or planetesimal and some of its ejected fragments eventually reached the Earth’s orbit, falling through the atmosphere and ending up as meteorites on the ground — in the case of NWA 11119, falling in Mauritania at a yet unknown time in the past.
“The oxygen isotopes of NWA11119, NWA 7235, and Almahata Sitta are all identical, but this rock — NWA 11119 — stands out as something completely different from any of the over 40,000 meteorites that have been found on Earth,” Srinivasan said.
Building blocks of planet formation
Most meteorites are formed through the collision of asteroids orbiting the sun in a region called the asteroid belt. Asteroids are the remains from the formation of the solar system, some 4.6 billion years ago.
The chemical composition ranges of ancient igneous meteorites, or achondrites, are key to understanding the diversity and geochemical evolution of planetary building blocks. Achondrite meteorites record the first episodes of volcanism and crust formation, the majority of which are basaltic in composition.
“This research is key to how the building blocks of planets formed early in the solar system,” said co-author Carl Agee, director of UNM’s Institute of Meteoritics. “When we look out of the solar system today, we see fully formed bodies, planets, asteroids, comets and so forth. Then, our curiosity always pushes us to ask the question, how did they form, how did the Earth form? This is basically a missing part of the puzzle that we've now found that tells us these igneous processes act like little blast furnaces that are melting rock and processing all of the solar system solids. Ultimately, this is how planets are forged.”
The next steps for the ASU team are to detail the chronology of this meteorite (and related meteorites) with new isotopic measurements. These new data will help even more precisely determine the age of this unique meteorite and the implications for the evolution of rocky bodies in the early solar system.
The Center's Meteorite Gallery joins more than 2,000 museums across America to offer free admission to military personnel and their families this summer, in collaboration with the National Endowment for the Arts, Blue Star Families, and the Department of Defense.
Blue Star Museums is a collaboration among the National Endowment for the Arts, Blue Star Families, the Department of Defense, and more than 2,000 museums across America to offer free admission to the nation’s active duty military personnel and their families from Memorial Day through Labor Day. The program provides families an opportunity to enjoy the nation's cultural heritage and learn more about their community, especially after a military move. A list of participating museums is available at arts.gov/bluestarmuseums.
“Visiting a museum is a great way to get to know a community—whether it’s in your hometown or a stop on a road trip,” said NEA Chairman Jane Chu. “We appreciate the enthusiasm of museums all across the country who open their doors for military and their families to spend time together and have new arts experiences.”
This year’s Blue Star Museums represent not just fine arts museums, but also science museums, history museums, nature centers, and dozens of children’s museums. Museums are welcome to sign up for Blue Star Museums throughout the summer by emailing firstname.lastname@example.org.
“As many military families spend the summer months moving from one duty station to another, or reconnecting with a parent who has returned from deployment, Blue Star Museums helps service members and their families create memories,” said Blue Star Families Chief Executive Officer Kathy Roth-Douquet. “Blue Star Families has great appreciation for the generosity of the museums across the country who roll out the red carpet for the families who serve alongside their service members. We are thrilled with the continued growth of the program and the unparalleled opportunities it offers.”
We are pleased to announce that Center Ph.D. Candidate Daniel Dunlap has been awarded the Dwornik Award!
The award was endowed in 1991 by Dr. Stephen E. Dwornik, who wished to encourage U.S. students to become involved with NASA and planetary science. The Dwornik Award recognizes outstanding student presentations (in both oral and poster categories) at the annual Lunar and Planetary Science Conference (LPSC). The awards are managed and judged by the Planetary Geology Division of the Geological Society of America.
We are pleased to announce that Center Ph.D. Candidate Soumya Ray has been awarded the highly competitive and prestigious NASA Earth and Space Science Fellowship (NESSF)!
Soumya's proposal, "A combined investigation of iron and silicon isotopes in meteorites: Implications for planetary accretion and differentiation", was one of only 24 selected from over 220 applications for this fellowship in the Planetary Science Research Program.
The NESSF program awards students from accredited U.S. universities pursuing Master of Science or doctoral degrees in Earth and space sciences, or related disciplines. The purpose of the NESSF is to ensure continued training of a highly qualified workforce in disciplines needed to achieve NASA's scientific goals.
Given her childhood fascination with the movie Armageddon, about a gigantic asteroid on a collision course with Earth, it’s not surprising that School of Earth and Space Exploration recent grad, Alexandra Perez, focused her studies here at ASU on meteorites.
Originally from Jacksonville, Florida, Perez was thrilled to learn in college that she could actually study meteorites. “When I held my first meteorite while working on my senior thesis, I instantly knew this is what I wanted to study.”
Since beginning her master’s degree at ASU in geological sciences, Perez has conducted over 130 experiments to determine how chondrules (a mineral grain present in some stony meteorites) form. Research on these primitive specimens may help us better understand the evolution of the early solar system.
Given her interest in meteorites, It’s not surprising that Perez’ favorite spot on campus was the second floor of the Interdisciplinary Science and Technology Building, where the Center for Meteorite Studies is located. ASU has the largest collection of meteorites of any university (over 40,000 specimens) and a variety of meteorites are on display here, both behind glass, as well as some that you can touch.
When asked the best piece of advice she’d give to those starting college, Perez recommends students push themselves beyond their limits and comfort zones. “This is the only way you can find what you are capable of and you will surprise yourself along the way,” she says.
And she practices what she preaches. Alexandra has been described by her advisors and instructors as both positive and persistent. She has also overcome tremendous challenges, including surviving a brain tumor prior to starting her degree.
Her plans after graduation include a trip to New Zealand and Australia, as well as spending time with family. After a break, she plans on pursuing a Ph.D. and continuing to raise awareness of brain tumors and supporting the search for a cure.
Center students and scientists recently took touchable meteorites to the closing weekend of the Phoenix Zoo's Dinosaurs in the Desert exhibit, and DÍa del Niño event.
How do you take on a T-Rex in the wild? With a well aimed Canyon Diablo iron meteorite, of course!
Ph.D. candidate Zack Torrano demonstrates the proper stance to take, with outward turned throwing hand, and off-hand extended for balance. This minimizes the chances of slipping and falling while attempting to attack a dinosaur, which can be a fatal mistake.
Ph.D. student Gabriel Franco shares his enthusiasm for space rocks with aspiring young scientists.
Ph.D. candidates Emilie Dunham and Zack Torrano describe the meteorite that wiped out the dinosaurs 65 million years ago, and invite visitors to hold a rock from space.
Despite his best attempts, Zack was unable to convince this feathered dinosaur to trade one of her eggs for a meteorite.
A research unit of the School of Earth and Space Exploration.