Planetary Sedimentology Lab at Penn State

We just wrapped the final class for GEOSC 497-001, Mars Sedimentology! This was a mixed grad-undergrad project-based course I designed to introduce students to real Mars datasets, advanced concepts in sedimentology, some basic statistical methods, and a bit (a lot) of ArcGIS and Python. Over four ~month-spanning projects, we learned about channel-belt stacking in alluvial strata, the mechanisms behind branching patterns in river deposits, the topography and internal structure of river deltas, and the kinematics of submarine channels.

The real stars of the show were the topographic datasets, particularly from HiRISE stereo data. Stereo topography, especially at this resolution, is what makes quantitative sedimentological approaches possible with orbital data.

I think – and hope – that each student got something unique out of this class. We had a total of 8 guinea pigs representing undergrad and graduate geoscience students, as well as undergraduate astronomy majors with a planetary science focus. I imagine different aspects of the course mattered in different ways to these different students.

To me, the most important take-home is that, where we see sedimentary deposits on Mars, there is a high likelihood that those deposits are time-integrated! That is, we’re not viewing a frozen-in-place landscape dating back to ancient Mars, but rather exhumed sedimentary deposits with a lot of evolution through time wrapped up in their geometry. These students now know how to test that idea, and how powerful having this time-evolution component can be in understanding these ancient martian environments!

I’m already looking forward to improving things, streamlining the experience, and teaching Mars Sedimentology again in Spring 2025. To Penn State students interested in taking this Geosciences course next year, we accommodate a wide array of scientific backgrounds.

A big thanks to those who participated this semester, including

• • • • • Juliana Drozd
        • Brandon Fong

-Ben

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

 

 

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

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

 

 

I’ll be presenting Monday at 2:50 pm in the Mars Paleohydrology session.

On Tuesday, Zach Baran presents his poster on experimental erosion of shoreline topography.

On Thursday, Kaitlyn Stacey presents her poster on dune cross-bed geometry.

SEPM is also tweeting about Planetary Research Group presentations – follow along on their Twitter!

 

-Ben

 

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

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

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

Adrienne Berard put together a nice writeup for Penn State News of our recent Journal of Geophysical Research: Planets paper about the stratigraphy of an ocean margin on Mars. Find it over in the Press tab, just above!

-Ben

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