Geologic Mapping on Mars

Rose here –

One of the famous first stories of modern geology involves the publishing of a geologic map of England by William Smith in 1815. This was one of the first geologic maps made by a geologist doing fieldwork, which often involves camping out in an area for a few days, weeks, or months to find out as much as possible about the area to be mapped. Geologists walk around the area to be mapped and take measurements of what types of rocks are there, how thick each layer is, whether they are tilted or faulted, etc. They may also take samples of the rocks to do chemical tests or look at them under a microscope. Field geologists look at the morphology (shape) of the landscape in order to map the locations of ridges, depressions, and other features and determine the processes that formed them.

Several students (I am on the far right) mapping the “Banana Canyon” area in southern Idaho at senior field camp, summer 2014. We spent a couple days roaming around this area, taking measurements and notes and figuring out what kind of rocks were here. Then we would go back to camp and use our measurements to make a cross-section showing the different layers of rocks and where faults or folds might have occurred. Our long sleeves, pants, and hats were so we didn’t get sunburned – it was actually pretty hot that day (and every day)!
My experiences in geology as an undergraduate major were largely field-based, going on many field trips to various places and taking notes and measurements at different locations. But how do you make a map when your field area is on average 140 million miles (225 million km) away from Earth? I had never considered studying geology in a field area anywhere other than Earth, but shortly after starting my master’s degree I had the opportunity to work with a team of collaborators to create a geologic map of a small region on Mars. Geologists can now create maps of planets, moons, and asteroids using high-resolution images from spacecraft orbiting Mars, Mercury, the Moon, and many other bodies in our solar system. I was excited to begin this project, but first I had to learn a whole new set of skills than what I had used in field camp as an undergrad.

There are several software programs scientists can use to make maps using images and other types of geospatial data. These software programs are collectively called Geographic Information Systems (GIS). GIS software is used in many different fields for different kinds of projects and analyses. For example, biologists might use GIS to make maps of where certain species of animals live in relation to cities, lakes, highways, etc. Geologists might use GIS to produce maps showing the location of certain types of rocks or geologic features.

For my master’s project, I used a mosaic (several images digitally “stitched” together) of images from the Mars Reconnaissance Orbiter’s (MRO) Context Camera (CTX). To identify a feature in these spacecraft images, it needs to be big enough to have at least two pixels across it each way (so a minimum 2×2 grid). CTX images of Mars have a resolution of 6 meters (m) per pixel, which means they can be used to find features about the size of a large room. When I upload these images into my GIS program, I can zoom in and out to see features better. When I find a feature that looks interesting, I can mark its location and shape by making a new “layer” and drawing on the image. I use different layers for different types of features, and each layer can be turned on and off so I can see where different features are in relation to each other.

Here I am doing a totally different kind of mapping! I am using the GIS software ArcMap from ESRI to map the locations of wrinkle ridges in my study area, a place called Aeolis Dorsa in the eastern hemisphere of Mars near the equator.
My first step in mapping was actually not mapping, but reading lots of previously published papers about the geology of my study area and about the particular type of feature I wanted to map. I am mapping a type of ridge on Mars called a wrinkle ridge. This ridge is formed by tectonic contraction and is found in layered igneous or sedimentary rock units. Once I had read as many papers as I could find on wrinkle ridges and made several tables summarizing the various types of information on them, I could finally start mapping. It took quite a while for my eyes to get used to looking at these images and to pick out the features I was looking for. However, wrinkle ridges have several common distinguishing characteristics, mentioned in many published papers, that I used to double-check my visual identification. When I had gone over my whole study area several times and marked any feature I thought could possibly be what I was looking for, I went over it again and narrowed down the number of features using my list of common characteristics. Learning to identify wrinkle ridges and other features visually is a good skill and I spent a great deal of time trying to do so. However, it is also important to make my results understandable and reproducible by other scientists. Thus I need to be able to clearly show how I identified a feature as either a wrinkle ridge or not. With my list of common characteristics, I decided how many of them would be required to determine if a feature is a wrinkle ridge, and within those determined to be wrinkle ridges I further divided them by how many characteristics they had into certainty levels: Certain, Probable, and Possible. This process allows my work to be reproduced or at least easily followed by any future scientists studying the same type of features.

I’ve been working on this project for about two years now and while it’s been a lot of hard work and tired eyes, it so rewarding to see my map finally coming together. While I’ve been mapping one type of feature, other scientists in my research group have been mapping different types of features and we are about to put them all together and make one complete map. When we have all our mapping together on one map, it will be published as an official United States Geological Survey (USGS) geologic map. Stay tuned!

A journey into geology

Rose here –

Howdy! Today I want to share with you some of my journey to get to where I am in grad school. I am currently finishing up a master’s degree in geology, but I didn’t always plan on going to grad school, or even going into science.

Growing up in the Pacific Northwest, some of my favorite books were the ones on earthquakes and volcanoes, which were both very real geologic hazards in the area I lived. Someone gave me a book on identifying rocks and minerals and I started a rock collection with rocks I found down by the river or in my parent’s driveway. My grandpa loved rocks and geology and taught me how to identify various rocks and minerals and even pan for gold with sand and gravel he brought back from the Mojave desert in California.

However, by the time I got to high school I was struggling with algebra and higher level science classes and didn’t think I had what it takes to be a scientist. There were no high school level geology classes offered at that time and I didn’t even know that “geologist” was an actual job title. I discovered that I was really passionate about education and helping folks with special needs so I decided to go into special education.

This is the group photo from the 2012 GEOL 210 course at CWU, an introductory field methods course. We took this photo standing in the White Mountains near Bishop, CA with the Sierra Nevada range in the background.

After high school, I started at nearby Green River Community College (GRCC) so I could save money by still living at home. In the spring of my second year I had to take a science elective and ended up in Geology 101. I could write a whole post on how important geology classes at community colleges are, but I’ll save that for next time. This class quickly became my favorite class from my time at GRCC. The professor focused on how geology can be useful in our daily lives by framing each unit in terms of local geologic hazards to consider when buying a house or how to know what geologic processes have occurred when looking at a landscape. This made geology seem very interesting and relevant.

Now that I knew what geology was all about and what geologists do, I started seriously considering a career as a geologist. I loved the idea of studying the earth and the processes that formed it and are still shaping the landscape today. I especially loved learning about different hazards that affect people’s lives in different places in the world and how geologists can help prepare for and mitigate after disasters. The accelerated pace of college classes seemed to be what I needed to finally figure out higher level math, and I was actually enjoying my algebra and chemistry classes. I started paying attention to geology stories in the news and was in my professor’s office almost every day to talk about a recent earthquake or a cool rock I had found, etc. I decided to pursue a BS degree in geology after finishing at community college and looked into quite a few undergrad programs from Alaska to Ohio. I settled on Central Washington University, about an hour and a half from my childhood home, but on the other side of the Cascade Mountains so I got to experience a totally different type of climate and landscape. In the CWU geology department, every class that could had at least one field trip, and often more. There were good examples of almost every type of geologic process within a couple of hours of our university. I loved every class I took there and it seemed like every day was constantly reaffirming that this was where I was supposed to be. Even the informally dubbed “weed-out classes” I loved, which I was assured was the whole point: if you loved even the classes with 4 hour labs and 25+ hours of work outside of class time, slogging through all kinds of geology problems, then you were in the right spot.

Here we are setting up a geodetic survey station during a geodesy field course at CWU. We were down near Three Sisters, OR and used the GPS data we gathered to study how the earth is deforming (moving up, down, or sideways) near these active volcanoes.

When I was finishing up my bachelor’s degree and pondering what was next, I thought that I wanted to go to grad school, but not just yet. I had been in college for 5 years at that point and felt like I needed a little break. But then I attended a national Geological Society of America meeting in Vancouver, BC during the fall of my senior year. This is one of the biggest conferences for geologists every year, and there were scientists from all over the US and the world and from every branch of geology. I saw so many cool projects and was so inspired by all the interesting geology that I decided I wanted to be a part of that as soon as possible. When I got back I did some research and started sending e-mails to professors I was interested in working with. I didn’t get a single response to my first round of e-mails and was kind of discouraged. But I still really wanted to get in on some cool geology research so I sent out a second round of e-mails to completely different professors and heard back from all of them within a couple days! I was so excited to begin this journey and immediately started the application process, took the Graduate Record Exam (GRE), and waited eagerly for acceptance letters. I got in to two of the four schools I ended up applying to. I had a choice between living in Tennessee or Alabama, but decided I wanted to be closer to the Great Smoky Mountains (a dream destination since my childhood) so I went with Tennessee.

Here we are sitting next to the Borah Peak fault scarp in Idaho. This was during senior field camp and we had to map out the extent of the scarp and measure how much deformation had occurred.

I moved to Knoxville and started my master’s in the Department of Earth and Planetary Sciences at The University of Tennessee, Knoxville. I was prepared for an adventure, but even this one didn’t go the way I thought it would. My first project didn’t quite pan out the way I thought and I ended up switching projects and advisors toward the end of my first semester. This is way more common than you hear about…I have several other friends who switched advisors or projects as well. Sometimes it’s a personality or advising style issue, or sometimes the project itself is just not a good fit. The thing I had to keep reminding myself during this time was that it wasn’t a failure to change projects and not do what I thought I was going to, it just meant it wasn’t a good fit for me.

So I was on to my new project: contributing to a geologic map of a local area on Mars. Before starting this project, I didn’t know scientists even had the data to do geology on Mars! I was a little disappointed to not be doing field geology on Earth, but I thought this was a great opportunity to learn something new and expand my skills in geology and mapping. I discovered in undergrad that I loved mapping and structural geology (faults and earthquakes and how rocks move and deform). This project combined both by allowing me to map structural features on Mars and try to figure out a little about how they formed and contributed to the landscape in my study area. Throughout my time on this project I have come to appreciate the

I’ve been on this project for two and a half years now and I’m nearly done and thus began pondering again: what’s next? I applied to lots of jobs in geology or related fields and got only one phone interview. This is fairly common, but it’s still difficult not knowing what’s next. Then over Christmas break I remembered that in undergrad I had considered someday being a librarian. I am really passionate about reading and writing, about the community spaces libraries provide, about making information available and accessible to all. I had sort of pushed this idea to the side while pursuing my master’s in geology, as a “someday dream”. Now that I was almost done with my geology studies, I decided maybe “someday” was actually “now”. I did some research, talked to friends who were librarians, and sent more e-mails to professors. I ended up applying and being accepted to the Information Sciences program at UT to start in Fall 2018. I am so excited to explore the possibilities of combining my passion for geology and information: some potential jobs include positions at state geology libraries, the United States Geological Survey (USGS) library, national labs, or as a subject librarian at academic libraries.

Geologic evidence for changes in paleoclimate on Mars

Dichotomies in the fluvial and alluvial fan deposits of the Aeolis Dorsa, Mars: Implications for weathered sediment and paleoclimate

Robert E. Jacobsen and Devon M. Burr

What data were used? In this study, the scientists used images and topographic data from satellites orbiting Mars. This data was collected using two instruments:

CTX (Context Camera) images from the Mars Reconnaissance Orbiter were used to map the locations and types of fluvial and alluvial (formed by flowing water) geologic features in the study area. Images from this camera can resolve features about the size of a room (5-6 m or 15-20 ft).

MOLA (Mars Orbiter Laser Altimeter) topographic data from the Mars Global Surveyor was used to find elevations of the different features that were mapped and infer their relative ages. For example, if one feature is on top of another, the higher one is inferred to be younger.

Methods: The authors made a geologic map of the Aeolis Dorsa region using images from thes two datasets described above. The Aeolis Dorsa region is a rectangular area roughly 500 x 500 km. There are many types of sinuous (snake-like) ridges in this area that were formed by wind depositing or eroding the sand and rocks, by flowing water, or by tectonics. Some of these sinuous ridges are interpreted by geologists as inverted fluvial and alluvial deposits. Fluvial refers to transport by rivers or streams and alluvial refers to transport by intermittent water, such as on a floodplain. These types of features are formed by water carving out a river channel and depositing rocks and sediments within that channel. When the water dries up, these rocks and sediments become hardened by a process called chemical cementation, which means the rocks and sediments are “glued” together chemically by minerals dissolved in the water. Later, the rocks around these indurated sediments are eroded and what was a channel now appears as a ridge. This enables geologists to use the inverted channels to map out ancient river deposits.

Map of the Aeolis Dorsa region with colors showing different topographic elevations. The red and brown are higher elevations and blue and green are lower. The brightly colored lines represent the different types of fluvial and alluvial features that were mapped, and the black boxes are smaller areas studied in detail.

Results: The locations and relative ages (which deposits are older than each other) of the inverted channels found in the Aeolis Dorsa region show two things. First, the deposits in the southern part of the region required more water and mud to form, implying that there was more rain and more cohesive (“sticky”) soil good for making mud in the south than in the north. Second, the amount of precipitation evolved over time. The older deposits were mainly fluvial and required more water/precipitation than the younger deposits which were mainly alluvial.

Why is this study important? This study is important because it shows how the climate varied over time and within different areas of the same local region on Mars. The study also used terrestrial analogs, which are places with similar features on Earth. This is important because we can’t yet go to places on Mars and directly sample the rocks, so scientists use these terrestrial analogs that they can directly sample to compare what they see in the geology of Mars.

The big picture: Understanding the local variations in paleoclimates on Mars is important to scientists because studying the past climate of Mars can tell us about past “habitability” – the availability of water and other resources for life. Studies like these can also help scientists find good places to land and explore further on future missions to Mars.

Citation: Jacobsen, R. E., and Burr, D. M., 2017, Dichotomies in the fluvial and alluvial fan deposits of the Aeolis Dorsa, Mars: Implications for weathered sediment and paleoclimate: Geosphere, v. 13, no. 6, doi:10.1130/GES01330.1

Attending Professional Conferences as an Undergraduate

Rose here –

Attending professional conferences can be a lot of fun. I have had the opportunity as a graduate student to attend several geology conferences around the country, but the first conference I attended was as an undergraduate senior geology major, and it set me on the course to pursuing graduate school.

Conferences for many professional organizations move around to different cities from year to year, making it easier for people in different regions to attend. During my senior year as an undergraduate, the annual meeting of the Geological Society of America (GSA) was held in Vancouver, British Columbia, Canada, just a few hours’ drive from my university, Central Washington University. Because of this, our department encouraged as many students to go as were able, since it was so close that we would not have to pay for plane tickets or other large travel expenses. There are several scholarships and travel grants available to students who are presenting research to attend professional conferences, but since I did not participate in a research project as an undergrad I was not able to receive this type of funding. To keep costs down, many of the students and professors from my department carpooled up to Vancouver and we crammed as many students as we could into a cheap hotel room a few blocks from the conference center.

Once we got to Vancouver and got settled in our hotel rooms, it was easy to see that this was the perfect place for a geology conference. It was my first time in Vancouver and I fell totally in love with the views. There were beautiful forested green mountains coming down right into the harbor. It was easy to imagine the subduction of the Farallon plate under the North American plate, forming the tall, (geologically) young mountains, followed by the giant glacial ice sheets covering the area during the last ice age and then retreating to leave behind such a beautiful landscape for us to enjoy.

During the conference, I was able to attend many interesting talks and poster presentations on a wide variety of geological topics, including paleontology, planetary geology, structural geology (earthquakes and tectonics), volcanology (volcanoes!), and metamorphic petrology (studying rocks that have been heated and transformed under high pressure without being totally melted). I was delighted to find that there were so many people studying so many interesting facets of geology, and was inspired to check out some ways to get involved in research myself.

There were many events happening during the week of GSA, some specifically aimed at students, and I attended as many of these as I could. Most were free or very affordable ($5-$15) for student attendees. There were a few networking events such as career lunches with professionals with jobs in industry (e.g., oil & gas), government, and academia. These lunches usually included a panel discussion or Q&A, followed by time to just mingle and talk to professionals and fellow students. Most GSA technical divisions (Structural Geology, Sedimentology, Planetary, etc.) had formal business meetings and social events (often combined) during the week of GSA. Some of these were free and some were ticketed, though if they charged they likely had a reduced rate for students. I found that these meetings were a good way to meet folks in fields of geology I thought I was interested in, and most of the people there loved to talk to students about what they do. One of my favorite events at GSA every time I’ve been is the Association for Women Geoscientists (AWG) networking breakfast. This is their annual business meeting, but also a way to get a good breakfast and meet other women geoscientists during the conference.

The exhibit and poster hall was one of the biggest rooms I had ever seen. There were hundreds of poster presentations of people’s work. This was a good way to spend time if I had an hour or two free. Walking around and looking at all the posters was a fun way to learn a lot about branches of geology that I knew very little about. There were also quite a lot of exhibitor booths for universities, geological equipment manufacturers, and various companies that hire geologists. Many of them were giving away free stuff (bookmarks, flash drives, pens), so it was fun to go around and see what I could get. I also loved walking around to all the booths for university geology programs and talking to students from other schools.

As a result of being exposed to all this cool science, I ended up applying to grad school for geology, and am now in the last semester of my Master’s degree! If you are an undergraduate (or even high school student) interested in science and you have the opportunity to attend a science conference in your area I highly recommend it.