I Finished My Undergraduate Thesis!

Mars is currently very cold and dry, with conditions that do not support liquid water. However, earlier in the planet’s history, conditions may have been more amicable to liquid water- perhaps even enough so for an ocean to be present in the northern hemisphere until ~3.5 Gya. Laterally extensive paleoshorelines, originally interpreted via textural differences from orbital imagery of the martian surface, have been used as evidence for this ancient ocean. However, these interpretations remain contentious.

My thesis, titled “Numerical Modeling of Lake Bonneville Paleoshoreline Erosion at Mars-Like Rates and Durations,” investigated the plausibility of paleoshoreline features being preserved and identifiable today- after 3.5 billion years of slow martian erosion. Here on Earth, we have younger, uncontested paleoshorelines, which are determined via their topographic features- subtle breaks in hillslope with locally high slopes- rather than textural differences. These subtle topographic features are highlighted below in a transect containing Lake Bonneville (a Pleistocene paleolake from modern day Utah) paleoshorelines.

We ran several experiments and modeled linear hillslope diffusion on topographic data containing these three paleoshorelines at Mars-like rates and durations to investigate their survivability. Despite the slow erosion on Mars, given enough time (say, 3.5 billion years), we suspected that any identifiable trace would be eroded away.

The experiments produced outcomes of either paleoshoreline survival or erosion depending on the variables modified during each run. The figure below shows the results for two of the experiments after the modeled 3.5 billion years of erosion. The top transect shows a case in which the shoreline features were completely smoothed out and lost, and the bottom shows a case in which they persisted.

However, other, non-diffusive processes also erode Mars’ surface, and likely to a greater effect than diffusive hillslope processes. Because these other erosional forces (e.g. aeolian abrasion) are non-diffusive processes, they were not modelled here. So, we interpreted our results showing the unlikelihood of the subtle topographic features indicative of paleoshorelines still being preserved for us to observe on present-day Mars.

If you would like to read my thesis, you can find it here! This semester I plan on continuing this research to find statistical ways to analyze the initial and resultant topography, as these results were based primarily on visual interpretations.

-Zach

 

 

Busy October in the Planetary Sedimentology Lab

It’s been a good month in the Planetary Sed Lab! We had a great visit from incoming PhD student Vincent Soldano, who is wrapping up his undergrad at the University of Nevada at Reno and starting up here in January.

We’ve had some nice coverage by Addie Berard of our recent NASA-funded GRL paper. I’m proud of this work – it combines Mars rover observations, satellite observations, 3D seismic reflectance volumes from Earth, and Landlab landscape evolution modeling. We suggest that we may be missing a lot of fluvial stratigraphy on Mars because we haven’t recognize all of the associated landforms generated along the all-important eolian erosional windows. At most places on Mars, exhumed channel belts seem to form fluvial ridges, but here we show that may not hold everywhere!

We’ve also had a (long-brewing) project published in Geology about interpreting cross-bed planview widths. I’m looking forward to sharing this work at next year’s SEPM conference – join us there! Abstracts are due Oct. 30th.

-Ben

Planetary session at SEPM conference in May 2024, Flagstaff, AZ

Libby Ives (JPL) and I planning to convene a planetary session at SEPM Society for Sedimentary Geology’s International Sedimentary Geology Conference next May in Flagstaff, AZ, USA! I really think this could be a great chance for planetary surfaces folks and Earth-bound sedimentary geologists to interface, moreso than LPSC and even AGU or GSA. I’m excited to see abstracts, and to see everyone in Flagstaff next year! Abstracts are due October 15. Find more info here!

 

-Ben

 

 

Zach’s LPSC 2023 Abstract – Mars Shoreline Erosion

Hello! I have been working on my senior thesis for a few months and decided to submit my work thus far to this year’s Lunar & Planetary Science Conference. Here is a look at the abstract, titled ‘Numerical Simulations of Lake Bonneville Shoreline Erosion at Mars-like Rates and Durations,’ for those interested!

We used digital elevation model (DEM) data from Utah to run a diffusivity model on the known and preserved shorelines of paleolake, Lake Bonneville. The proposed shorelines on Mars are contentious, with several arguments existing for and against their preservation.

The goal of my project was to see if the Bonneville Shorelines would remain recognizable after being eroded at Mars-like conditions and timeframe. Models were run on both unmodified and upscaled shorelines. The results showed that though the subtle, smaller shorelines became unrecognizable, the upscaled shorelines with more exaggerated topographic features may be able to stand the test of time.

I am excited to attend my first conference and present this work!

-Zach

Kaitlyn’s LPSC 2023 abstract- Answers in the Dunes

Hello everyone! I am very excited to share my abstract for this year’s upcoming Lunar & Planetary Science Conference, titled “Planform Architecture of Fluvial Cross Strata Within the Cedar Mountain Formation, Utah with Applications to Mars.”

This presentation will outline the results of our recent field work in Utah investigating how the distribution of cross set widths in plan view can be compared to the distribution of cross set thicknesses in cross sectional view within fluvial deposits, and how these findings can be applied to planetary datasets.

Also, as is LPSC tradition, I wrote a summary haiku about our work:

Cross sets from above

Widening our perspective

Answers in the dunes

-Kaitlyn

Three LPSC 2023 abstracts from the Planetary Sed Lab

At this upcoming LPSC, I will be presenting our recent Journal of Geophysical Research: Planets manuscript about evolving paleoshorelines recorded by deltaic and submarine sedimentology at Aeolis Dorsa, Mars.

The Planetary Sedimentology Lab has a good showing this year! Kaitlyn and Zach will also be presenting. Keep a lookout – they’ll be posting about their abstracts soon.

-Ben

SEPM Planetary Research Group meeting

Monday night at GSA, the SEPM Planetary Research Group held their first ever in-person meeting! Turnout was small but engaged, and we’re very excited to hold more in-person meetings in the future as we grow the group. Thanks to everyone who joined! Please send me an email, or even comment here, if you’d like to officially join the group to make sure you don’t miss any relevant notices in the future.

 

-Ben

Welcoming new Planetary Sedimentology Lab members

This semester, we welcomed Kaitlyn Stacey (PhD student) and Zach Baran (undergraduate) to the group!

Kaitlyn earned her BS and MS in Geology from the University of Texas at Dallas. Here is what she has to say about her research interests:

My research interests revolve around using morphology to characterize the lithological properties of sediments and the ancient landscapes in which they formed. I am motivated by understanding how surface processes shape the Martian landscape and relating what we know about these processes on Earth to other planets. I am currently working on studying how fluvial dune morphology in inverted ridges in Utah can help us understand similar fluvial ridges on Mars, and ultimately the history of water and erosion on Mars. When I’m not doing field work, I enjoy spending time with my cats, Scully and Dax, and going spelunking.

Zach will be numerically modeling the evolution of topography on Mars.

 

-Ben