Eric Portenga
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drericp.bsky.social
Eric Portenga
@drericp.bsky.social
65 followers 72 following 76 posts
Geomorphologist and Quaternary Geologist on the Earth Science faculty at Eastern Michigan University

Landscapes • Erosion • Fire • Ice • Land use
Posts Replies Media Videos
drericp.bsky.social
New Paper Alert! 🚨 2nd of 2 #UndergraduateResearch studies led by a past #EMU #Geology student! Schmidt Hammer dating didn't work for us in the #GreatLakes. We muse on why we think our 'negative results' are still useful! #EarthScience #Glacial #Geochronology
onlinelibrary.wiley.com/doi/10.1002/...
Challenges in developing a Schmidt hammer exposure‐age dating calibration curve from glacial erratics in the North American Great Lakes
Against expectations, mean Schmidt hammer R-values measured on 34 glacial erratics across six moraines in Wisconsin exhibit no meaningful relationship to independently determined cosmogenic 10Be expo...
onlinelibrary.wiley.com
November 10, 2025 at 2:27 PM
drericp.bsky.social
Clear skies for the last few days means we can get out to do some #undergraduate #research on the Sturgis Moraine #Michigan, seeing whether we can reorient displaced #glacialerratics with a Schmidt Hammer 🪨 🔨 🧐

#geosciences #earthscience #geology #geomorphology #GreatLakes #EMU
Undergrads student standing behind a large glacial erratic in the woods Top-view of a glacial erratic all chalked up in preparation for measurement Undergrad student making Schmidt hammer measurements on top of the glacial erratic
November 4, 2025 at 5:38 PM
drericp.bsky.social
We made it! Today is the first day of the Great Lakes Earth Exchange guest speaker program at #EMU. 🥳 Ph.D. Candidate Ashley Scott from Western Michigan University is the first official member of the #GLEEClubEMU. Come hear her talk about Dolomite 🪨 at 2PM in 111 Strong Hall! #Geology #EarthScience
October 29, 2025 at 3:57 PM
drericp.bsky.social
Coming soon to #EMU, magnetic mineral separation!
🪨 🧲 ✨😍

#Geology
#EarthScience
#Magnets
#Research
Wooden Crate showing the SG Frantz company logo. Inside is a giant magnet
October 22, 2025 at 6:50 PM
drericp.bsky.social
Got into the field this week for a new student project who is creating 3D scans of dated erratics and measuring them to see if there are metrics that help distinguish between moved and unmoved rocks!
#MichiganErratics
#GreatLakes
#GlacialGeology
#EarthScience
#Geology
#UndergraduateReeesrch
#EMU
A student using an iPad to create a 3D scan of a glacial erratic in a forested setting
October 18, 2025 at 7:10 PM
drericp.bsky.social
The October #EasternMichiganUniversity College of Arts and Sciences October Newsletter is chockablock with updates on #Geography #EarthScience and #Archaeology research and work being done by me and my colleagues WITH our students.

#GreatLakes #MichiganErratics

sites.google.com/emich.edu/ca...
CAS Newsletter
STUDENT HIGHLIGHTS
sites.google.com
October 14, 2025 at 5:36 PM
drericp.bsky.social
SO excited to announce the inaugural line-up of the #NSF funded Great Lakes #Earth Exchange speaker series (aka the #GLEEClubEMU) at #EasternMichiganUniversity. We've got talks on dolomitization, #groundwater modelling, #archaeology, and #GreatLakes water #chemistry. All are welcome to attend!
Poster for the 2025-2026 line-up for the Great Lakes Earth Exchange speaker series at Eastern Michigan University. A QR code links to the a Geomorphology webpage with more information.
October 13, 2025 at 7:42 PM
drericp.bsky.social
@geodesaurus.bsky.social the Haunted Hydrology ologies episode was awesome! Heard your mother’s name mentioned, and was like, that’s familiar. Then it clicked, an Eastern Michigan University geo link! Thanks for representing all us Geos of the #GreatLakes!
October 13, 2025 at 5:30 PM
drericp.bsky.social
Very proud of my hometown! #Muskegon and west #Michigan are hidden gems of our region! #GreatLakes

www.mlive.com/environment/...
After 40 years and $84M in cleanup, Muskegon Lake comes off toxic list
Federal, state and local officials gathered to announce the formal delisting of Muskegon Lake from the Area of Concern program.
www.mlive.com
October 3, 2025 at 3:31 AM
drericp.bsky.social
Learned last week that EMU invites creation of Faculty research pages via Google Sites, so I had a go at creating a new page for all things #Geomorphology at #EasternMichiganUniversity (linking to the #Research page since the home page is my face). Updates ongoing

sites.google.com/emich.edu/ge...
Geomorphology @ EMU - Projects
Laurentide Ice Sheet Retreat from the Great Lakes Region, USA
sites.google.com
October 1, 2025 at 8:24 PM
drericp.bsky.social
That feeling of hitting "Submit" on a revised manuscript after Reviewers suggest Minor Revisions 😎

More details soon!

#Geology #Geomorphology #EarthScience #QuaternaryGeology #Research
September 17, 2025 at 8:17 PM
drericp.bsky.social
The #EMU #EarthScience Support #Laboratory is getting a makeover! Unboxed our new jaw crusher, plate grinder, and ro-tap sieve shakers today! Soon, #geology faculty will be able to do mineral separation in house! Just waiting on the magnetic separator 🧲

🪨🪨🪨
A sieve shaker, rock jaw crusher, and gravel plate grinder still strapped to their shipping pallets in a geology lab space
September 11, 2025 at 2:59 AM
drericp.bsky.social
Just learned about the 1954 Prospect Point #Rockfall at #NiagaraFalls. Amazing video footage of the rockfall as it occurred, too. Caused by dolostone dissolution over time. Will have to incorporate into my #Geomorphology course this fall.

blogs.agu.org/landslideblo...
The 1954 Prospect Point Rockfall at Niagara Falls
Amazing archive footage on Youtube showing the 1954 Prospect Point Rockfall at Niagara Falls in USA, which had a mass of 168,000 tonnes
blogs.agu.org
September 9, 2025 at 6:50 PM
drericp.bsky.social
Having grown to love #Australia during my time there in grad school, this is such good news!

Protected koalas? ✅
Cultural heritage led by Aboriginal rangers? ✅

Such great news! The world needs more new #NationalParks

🐨 🐨 🐨

www.abc.net.au/news/2025-09...
Announcement expected to lock in long-awaited Great Koala National Park
The long-touted Great Koala National Park is set to become a reality in New South Wales, protecting koala populations and other threatened species in the state's mid-north.
www.abc.net.au
September 6, 2025 at 11:38 PM
drericp.bsky.social
Brave the wind, and come on down! Check out the #EMU #Geography and #Geology Department table at #STEM Night at #Ypsilanti Community High School! See if you can complete the Rock Cycle, make jolly rancher stratigraphy, and put a 📍 on the Quaternary Map of #Washtenaw County! #EarthScience
Geology professor standing behind the Eastern Michigan University booth at Ypsilanti Community High School STEM night Table top rock cycle matching activity Baggies of crushed jolly rancher candy as stand-ins for sediment Printout poster map of the Quaternary Geology of Washtenaw County, Michigan
September 5, 2025 at 8:09 PM
drericp.bsky.social
Happy #InternationalDogDay to Max, our derpy #dog, lover of #LakeMichigan, and occasional #fieldwork assistant. Unfortunately, he doesn’t have a good nose for finding #MichiganErratics
Portrait photo of beagle-lab mix sitting amongst leafy garden Beagle-lab mix in the woods sniffing around a glacial erratic
August 26, 2025 at 9:27 PM
drericp.bsky.social
No, I’m not testing #MichiganErratics for allergies. Dots are #SchmidtHammer measurements that reveal the relative hardness of #rock surfaces. Strong rock ➡️ short exposure; weak rock ➡️ long exposure. #geomorphology #geology #geochronology #GreatLakes
Large granite boulder positioned on a leafy forest floor. Moss is growing on one side and there is a series of small dots/markings on the boulder surface in a grid pattern
August 26, 2025 at 8:50 PM
Reposted by Eric Portenga
theonion.com
Rock Looked Way Cooler Wet
Rock Looked Way Cooler Wet
August 25, 2025 at 10:00 PM
drericp.bsky.social
When the going gets tough sampling super hard #rocks and you bend a solid steel chisel, you know it is time to call in help from #Wolverine! #MichiganErratics

#geology #earthscience #geomorphology #fieldwork #research #icesheet #Quaternaryscience #Michigan #GreatLakes
Surface of a glacial erratic with a scale bar, sample ID sign, and a steel chisel bent in half Surface of a glacial erratic with three evenly spaced cuts in the rock, which looks like Wolverine from the X-men was here
August 25, 2025 at 1:13 PM
drericp.bsky.social
Been back out in the field this week collecting nearly the rest of samples needed to date the Port Huron Moraine built by the Saginaw Lobe of the Laurentide #IceSheet. Hunting for #MichiganErratics in the “Thumb” of #Michigan has been hard because of centuries of farming and other land use
Large boulders moved by farmers to a rock pile at the edge of a forest along with a rusty old car
August 24, 2025 at 12:22 PM
drericp.bsky.social
Struck out hunting for #MichiganErratics today, but got to explore a small old growth #forest with black maple, huge beech, and 200-year old hemlock trees at the Caro Airport. Yet another reason why the #GreatLakes are awesome! (Unfortunately, not open to public)

#EarthScience #Fieldwork #Michigan
August 7, 2025 at 12:26 AM
drericp.bsky.social
If you listen to the @npr.org Politics Podcast episode for today, you’ll hear yours truly reading out the timestamp, featuring #MichiganErratics and #EasternMichiganUniversity!

#geology #earthscience #fieldwork

podcasts.apple.com/us/podcast/t...
Trump's new tariffs set to take effect this week, but much is uncertain
Podcast Episode · The NPR Politics Podcast · 08/04/2025 · 17m
podcasts.apple.com
August 5, 2025 at 2:47 PM
drericp.bsky.social
Woohoo! First sample collected from the Port Huron #Moraine of the Saginaw Lobe of the Laurentide #IceSheet! How long ago? Guess we’ll find out in…oh…a year?! #Geology #Geomorphology #Research #MichiganErratics
August 2, 2025 at 1:33 AM
drericp.bsky.social
New #Geology & #EarthScience recruitment poster up in Strong Hall at #EMU. Hopefully this helps students decide to declare a Geo Major!
July 30, 2025 at 5:08 PM
drericp.bsky.social
Day 5: 🪨🪨🪨🪨🪨🪨🪨🪨🪨🪨

The first complete set of #MichiganErratics for my #NSF research project constraining Laurentide #IceSheet retreat through the #GreatLakes

1 down, 7 to go!

#Geology #EarthScience #Research #Michigan
July 26, 2025 at 1:04 AM