Using Cliffs on Earth to Understand Water Flow on Ancient Mars

Prolonged Fluvial Activity From Channel-Fan Systems on Mars

by: Gaia Stucky de Quay, Edwin S. Kite, and David P. Mayer 

Summarized by: Lisette Melendez

What data were used? In geology, there’s a basic pillar called “The Principle of Uniformitarianism”. It suggests that geologic processes almost always occur in the same manner and intensity now as they did in the past – which is why geologists can look at the rock record to learn more about Earth’s future. In the same vein, many geologic processes that occur on Earth, like landslides, volcanoes, and erosions, can be used to study the same processes on different planets!

This study focused on analyzing pictures of alluvial fans (finger-like deposits that are usually created when running water in arid or semi-arid (e.g., deserts) flows downhill onto a flat surface, as shown in Figure 1) on Mars taken by the Context Camera (CTX) on the Mars Reconnaissance Orbiter (MRO). The scientists also compared Martian alluvial fans to the ones found here on Earth using elevation data collected by the NASA Shuttle Radar Topography Mission. These alluvial fans usually mark the end of a water channel, so they can be used to study ancient water deposits on Mars.       

Figure 1: An example of an alluvial fan on the surface of Mars, taken by the Mars Reconnaissance Orbiter.

Methods: To study the channels of Mars, the CTX images were converted into digital elevation models, so information like width, slope, and height could be gathered from the data. The valleys on Mars were also measured for how closely they resembled a V-shape. Valleys shaped by rivers have a V-shape, while valleys shaped by other features, like glaciers, tend to have a U-shape.

After gathering all this data, the scientists desired to make an inference about the sediment on Mars, which is too small to be picked up by the camera. So, they turned to places on Earth that had alluvial fans that were very similar to the ones being studied on Mars: the Serra Geral in Brazil, the Great Escarpment in western South Africa, and the Western Ghats in India. These places were ideal parallels for the Martian surface because there’s little to no active tectonic plate movement in the area and the rocks are very well preserved over a long period of geologic time. The big difference is that instead of being placed along mountainsides or plateaus, the slopes that are being studied on Mars are usually along crater rims. 

Results: The channels studied on Mars were found to be less concave (curved inwards) and have very steep slopes, indicating a dry environment. The data on concavity and erodibility (likeliness to erode away) on the Martian alluvial fans was most similar to the data found on the South African slopes, which reinforces the idea that the environment was similarly hot and dry.

Figure 2: The cliffs of Earth (Brazil, South Africa, and India) used to study the sediment on the Martian surface.

Why is this study important? This study is another piece of evidence behind the idea that Mars was once full of water, before it underwent serious climate change. Understanding the history of water on Mars is crucial to understanding what conditions are necessary for life to evolve (which can help paleontologists learn about the first life on Earth, too!). It’s also interesting to note how we can learn more about planets that are millions of miles away by looking right here on Earth!

 The big picture: More than a billion years ago, water used to run freely on the surface of Mars, creating channels and alluvial fans. Scientists use images of the geologic features that remained after water was no longer on the Martian surface to learn more about the history of the Red Planet and the potential implications for human exploration. Learning more about the surface and climate of Mars is necessary for understanding the hazards and potential resources that would be encountered on a crewed mission to Mars.

Citation: Stucky de Quay, G., Kite, E. S., & Mayer, D. P. ( 2019). Prolonged fluvial activity from channel‐fan systems on Mars. Journal of Geophysical Research: Planets, 124, 3119– 3139.  https://doi.org/10.1029/2019JE006167

Understanding the geologic history of a near-Earth Asteroid through the lens of NASA’s OSIRIS-Rex mission

Craters, Boulders, and Regolith of (101955) Bennu Indicative of an Old and Dynamic Surface

by: K. J. Walsh, E. R. Jawin, R.-L. Ballouz, O. S. Barnouin, E. B. Bierhaus, H. C. Connolly Jr., J. L. Molaro, T. J. McCoy, M. Delbo’, C. M. Hartzell, M. Pajola, S. R. Schwartz, D. Trang, E. Asphaug, K. J. Becker, C. B. Beddingfield, C. A. Bennett, W. F. Bottke, K. N. Burke, B. C. Clark, M. G. Daly, D. N. DellaGiustina, J. P. Dworkin, C. M. Elder, D. R. Golish, A. R. Hildebrand, R. Malhotra, J. Marshall, P. Michel, M. C. Nolan, M. E. Perry, B. Rizk, A. Ryan, S. A. Sandford, D. J. Scheeres, H. C. M. Susorney, F. Thuillet, D. S. Lauretta and the OSIRIS-REx Team

Summarized by: Lisette Melendez

What data were used? Unlike geologic sites on Earth, scientists aren’t able to use field work to determine the geologic history of celestial objects like asteroids, planets, and distant moons. Instead, planetary geologists rely on data collected by scientific instruments on spacecraft, like cameras and spectrometers, to study these unreachable geologic features.

The data for this study was gathered from images taken by NASA’s ORISIS-Rex spacecraft, whose mission is to travel to a near-Earth asteroid named Bennu. Asteroids are the remains of the building blocks of our solar system that enabled the rise of planets and life, and most of them reside in the Main Asteroid Belt. However, sometimes asteroids are ejected and enter the inner solar system (i.e. the rocky planets: Mercury, Venus, Earth, and Mars), becoming near-Earth asteroids. This asteroid, Bennu, was chosen for the sample collection mission because of its proximity to Earth, large size (almost 500 meters long!), and carbonaceous (i.e., carbon-rich) composition. The carbon-rich part is important because these asteroids contain chemical compounds and amino acids that would have been present at the beginning of our Solar System. Even though the asteroid is relatively long compared to other asteroids, it’s only about as wide as the length of the Empire State Building!

The spacecraft is set to bring back a sample of this asteroid to Earth by 2023 for scientists to analyze. In late 2018, the spacecraft began the approach phase of the mission and used its cameras to take high-quality pictures of Bennu’s surface, as shown in Figure 1. These images are not only used to determine a good sample collection site, but scientists also use them to learn more about the geologic processes on Bennu’s surface. By weaving the images together, the team was able to produce a three-dimensional model of the asteroid and determine the location of boulders on the surface of Bennu. 

Figure 1: Shows the size of various boulders on Bennu’s surface. The arrows point towards identified fractures, which may be indicative of large impact events or stress caused by rapid temperature changes.

Methods: The surface of Bennu was mapped out by visually analyzing images taken by cameras on OSIRIS-Rex. Scientists combined image and radar data to measure the size and distribution of boulders on Bennu’s surface. By applying the same foundational geologic concepts observed here on Earth, scientists can draw conclusions about the geologic features on asteroids and what forces potentially formed them. 

Results: The orbit of a near-Earth asteroid is tumultuous, due to the possibility of collision with other asteroids and the forces exerted by Earth’s gravity, making a usual lifespan of a near-Earth asteroid only last around tens of millions of years. Usually, this would mean a young, consistently refreshed surface for these near-Earth asteroids. However, a detailed study of Bennu’s surface shows evidence of rocks that are hundreds of millions of years old – long before Bennu ever left the Main Asteroid Belt. 

Boulders are the most prominent geologic feature on Bennu’s surface. As shown in Figure 2, they can be found all around the asteroid. Scientists noted that the size of various boulders are simply too large for them to have been formed in Bennu’s current orbit, pointing towards the possibility they were created during larger asteroid collisions in the main asteroid belt. This indicates that studying the boulders further may aid in the understanding of Bennu’s parent body (i.e., where the rocks were originally created) and conditions in the main asteroid belt.

Another interesting result from the study is that even though the resolution of the images was not clear enough to depict fine-grained particles, the scientists measured thermal inertia (tendency to resist changes in temperature) and found that the results were consistent with the existence of fine-grained particles on Bennu’s surface. Come the end of 2020, the spacecraft will start up the TAGSAM (Touch-and-Go-Sample-Acquisition-Mechanism) instrument, blow nitrogen gas onto the surface to stir up dust, and collect the sample – leading to even more scientific discoveries on the asteroid front.  

Figure 2: Maps the abundance of boulders on Bennu’s surface, where red marks areas that are densely populated by boulders and blue marks areas where there are relatively less boulders.

Why is this study important? This study is a reminder of how fascinating geology is: scientists were able to predict the history of the asteroid solely by measuring the size and distribution of boulders on its surface. This group was able to differentiate between events that occurred while Bennu was in the Main Asteroid Belt versus a near-Earth orbit, which helps us understand the environment right outside of Earth and beyond. 

The big picture: By looking into the early Solar System, the data gathered in this study will help scientists understand the processes behind the formation of planets, as well as the origins of life. Additionally, the study will enhance our understanding of the evolution of near-Earth asteroids as well as the possibility of the asteroids impacting Earth.

Citation: Walsh, K.J., Jawin, E.R., Ballouz, R. et al. Craters, boulders and regolith of (101955) Bennu indicative of an old and dynamic surface. Nat. Geosci. 12, 242–246 (2019). https://doi.org/10.1038/s41561-019-0326-6

We’ve Seen This Before: What The Extinctions in Our Geologic Past Indicate About the Dangers of Current CO2 Emissions

Deep CO2 in the end-Triassic Central Atlantic Magmatic Province

Manfredo Capriolo, Andrea Marzoli, László E. Aradi, Sara Callegaro, Jacopo Dal Corso, Robert K. Newton, Benjamin J. W. Mills, Paul D. Wignall, Omar Bartoli, Don R. Baker, Nasrrddine Youbi, Laurent Remusat, Richard Spiess, and Csaba Szabó

Summarized by Lisette Melendez. 

What data were used? 

This study investigates the large-scale volcanic activity that would eventually lead to the end-Triassic Extinction, one of the top five most devastating extinction events for life on Earth, that occurred about 201 million years ago. The volcanic eruptions took place across the globe, leading to a massive sheet of volcanic rocks known as the Central Atlantic Magmatic Province, or CAMP for short. Considering that the volcanic activity took place before the supercontinent Pangea was fully split apart, CAMP rocks can be found in North America, Africa, and Europe, as shown in Figure 1. Scientists used both intrusive (magma that crystallized underground) and extrusive (magma that cooled on the Earth’s surface) rock samples to investigate the amount of carbon dioxide, a greenhouse gas, released into the atmosphere during these catastrophic eruptions.

Methods: By analyzing the concentration of the carbon dioxide bubbles (Figure 2) trapped within the crystals that were formed during the volcanic eruptions, scientists can determine the speed and frequency of the eruptions. After collecting more than 200 samples, the concentration of carbon dioxide within the rocks was determined using microspectroscopy: a method that shows the spectra of the sample in order to identify and quantify the various compounds that are present. 

Results: Overall, there was a high volume of carbon dioxide bubbles within CAMP rocks. Since CO2 is an accelerant for magma eruptions, the volcanic activity was likely hasty and violent. The rapid rise of CO2 in the environment means CO2-removing mechanisms, like weathering, aren’t enough to balance out the excess CO2. This leads to a carbon dioxide buildup in the atmosphere, accelerating global warming and ocean acidification.

 

Figure 1: A map of the boundaries Central Atlantic Magmatic Province in central Pangea, around 200 million years ago. It shows how wide-spread the volcanic eruptions were during this time.

Why is this study important? The study of CO2 saturation in rocks helps us understand the role that volcanism played in the buildup of excessive greenhouse gases in the atmosphere that triggered the end-Triassic extinction. It showed that the more rapid the release of CO2 into the atmosphere is, the more severe the environmental impact.

The big picture: This study can be used as a warning for current trends, considering that the amount of CO2 emitted during the CAMP eruption roughly equals the amount of projected anthropogenic (i.e., human-caused) emissions over the 21st century. Just like in the past, the current substantial rise in CO2 is leading to a global temperature increase and a surge in ocean acidification, but we are releasing CO2 much faster than at any other time in Earth’s history. Considering that these are the same conditions that led to one of the worst biotic extinctions in Earth’s history, it is vital to encourage our governments to implement radical climate change policies in order to slow the current rise of CO2 to prevent more environmental destruction. 

Figure 2: The black arrows point towards the bubble-bearing inclusions within the rock samples using light optical microscopy. The high concentration of CO2 within these bubbles indicates the magma was rich in CO2. These four samples are specifically orthopyroxene (Opx), clinopyroxene (Cpx), and calcic palgioclase (PI), and were sampled from Canada and Morocco.

Citation: Capriolo, M. et al. Deep CO2 in the end-Triassic Central Atlantic Magmatic Province. Nat Commun 11, 1670 (2020).

Lisette Melendez, Geology and Astronomy Undergraduate Student

Standing outside of NASA Ames, where Lisette worked in aiding the lunar landing mission!

What is your favorite part of being a scientist?

Ever since I was very young, I’ve always had a fascination with geology. In elementary school, I would tout around my battered copy of the Smithsonian handbook on rocks and minerals and take notes in my “research journal”. Rocks littered every available surface of my room, and my ears always perked up when we finally reached the Earth Science section of our science classes. What’s cooler than learning about Earth’s layers and how volcanoes form? During field trips, I would sometimes get separated from the group, too mesmerized by rocks that I found on the ground. Even with all these signs, it wasn’t until the end of my first year in university that I realized that I could become a geologist and work with rocks for a career. 

I started off in a field that I was pressured into but that I had no passion for. How could I miss geology as a career option? For many years prior, every geologist that I encountered in my textbooks were white men. While I was working on one of my assignments, I looked over to see what my friend was working on. The assignment was to use Steno’s Laws of Stratigraphy to determine what order the rock layers were deposited. I thought the assignment was fascinating while my friend looked at me with a strange face. They told me about their professor, Dr. Sheffield, and how passionate she was for geology and all the amazing fieldwork she’s done throughout her career. This was a mindblowing moment for me: it was the first time I learned about a female geologist. That same day, I went to the student affairs office and changed my major to Geology. 

From that day forward, I got to experience first hand what a difference doing what you love made in one’s life. My favorite part of being a scientist is simply that there’s always more to learn. Every single day, I wake up incredibly excited to go to class and learn about minerals, volcanoes, and paleobiology. I still remember being in my old major looking wistfully at the Mineralogy class on the USF course inventory. I’m forever grateful that now, that’s what I study all the time! I look over my room and now there are textbooks on planetary volcanism, astrobiology, and sedimentology that join the rocks scattered on various surfaces. Sometimes, I feel like I never really changed from that child who loved rocks: now, I’m just working to be able to collect rocks for the rest of my life.

What do you do?

Right now, I’m studying geology and astronomy at the University of South Florida. My future goals are to get accepted into a PhD program for planetary science, and then hopefully work on the research team that analyzes samples from the surface of Mars and become a curator at a natural history museum! 

Most of the research I do works towards uncovering the geologic past of celestial objects. It’s the perfect overlap between my two favorite subjects: geology and astronomy! Last summer, I conducted research about Martian ice caps at Brown University through the Leadership Alliance – an awesome program aimed at increasing diversity in STEM (read my Time Scavengers post about it here!). I also interned at NASA, where I helped write the code of a navigation program that would assist scientists locate ideal landing areas on the Moon. This upcoming summer, I’m really excited to be working with the Smithsonian National Museum of Natural History on analyzing meteoritic samples collected by NASA’s OSIRIS-REx mission. The samples collected contain information on the earliest history of our solar system! I’m using my time in undergraduate studies to get a clearer idea of what branch of planetary science I’d like to delve into in graduate school.

Volunteering as a mentor for NCAS (NASA’s Community College Aerospace Scholars).

How does your research contribute to the understanding of climate change and the betterment of society in general?

I believe research in the planetary sciences helps humanity as a whole by illuminating our role in the universe. By addressing the questions of the universe,  the answers to our day to day problems become clearer through perspective. It’s easier to plot out humanity’s destiny and how to build a better society for everyone by figuring out where we came from and how the universe around us is changing. This is particularly important when considering the future of humans in space. Being able to find geologic analogs of celestial terrain (like the Martian surface) on Earth will help us decide which crops and structures work best for the Martian environment. As we continue exploring the universe, it’s important to keep in mind universal codes of safety, planetary preservation, and anti-imperialism in order to avoid harming the new environments we enter.

What methods do you use to engage your audience and community? What have you found to be the best way to communicate science?

One of the first pieces of advice that one of my mentors, Dr. Mustard, bestowed onto me was that “science is never done in a vacuum”. Collecting scientific data is an incredibly exciting part of research, but it’s also essential to communicate your findings with others to increase scientific literacy and humanity’s pool of knowledge. Science is all about sharing what you’ve learned and what you’ve experienced. It is much more rewarding involving different perspectives and helping everyone feel included. Through my officer positions at two clubs at USF, the Geology Club and the Contemporary Art Museum Club, I promote the importance of STEAM and interdisciplinary research. I believe one of the keys to successful science communication is to express why one’s excited about the topic and to make it relatable to what others are interested in. I’m really excited to join Time Scavengers as a science communications intern in order to hone in on this essential skill and become a better scientist overall.

Standing at the base of the 40 foot radio telescope at Green Bank Observatory!

What advice do you have for aspiring scientists?

My advice would be to just take a moment and think about what you really want from life. I’ve spent countless years just trying to follow what others expected me to do that I never really thought about what I wanted to be. Following the path others decide for you is no way to live your life. You’re the one who will have to live out your career path, so choose one you’re passionate in! There’s definitely space for you! There is such a wide range of fields, from studying bugs to glaciers, you deserve to make your mark the way that you want to.

Finding where you belong is essential to unlocking the zeal that will pull you through obstacles and challenges. Prior to joining the geology department, I was a very shy and reserved person. However, my passion for geology and astronomy (and the endless kindness from geologists) gave me the courage to overcome my anxieties and become resilient in the face of adversity. I transformed from a quiet and socially anxious person into the president of my university’s Geology Club and founder of USF’s Society of Women in Space Exploration Chapter. Openly doing what you love will also surround you with like-minded individuals that are the key to building a good support group! My favorite part about becoming a geologist would definitely be being able to network and meet others who are just as passionate about rocks as I am. It’s exhilarating, being friends with geologists and gathering around in the parking lot of a Waffle House to examine an outcrop. The feeling of togetherness is unmatched.