Dr. Shannon Cofield 🪨🗺️🌊
@geoshanz.bsky.social
Geological Oceanographer | Researching sediments from the Deep Sea to Mars
• Ph.D. in tiny Arctic rocks, oceans, + squiggly lines
• Exploring extreme environments w/ robot friends
✍️ https://geoshanz.blogspot.com
Prev 🐥: @ MarsRoverMapper (ODU+NASA-JPL)
• Ph.D. in tiny Arctic rocks, oceans, + squiggly lines
• Exploring extreme environments w/ robot friends
✍️ https://geoshanz.blogspot.com
Prev 🐥: @ MarsRoverMapper (ODU+NASA-JPL)
Also 100% on par with my Navy experience. 🤣 Happy Vets Day!
November 11, 2025 at 3:19 PM
Also 100% on par with my Navy experience. 🤣 Happy Vets Day!
For those interested, here's some additional information about our paper (and our proxy) 🙂 Thanks again for sharing @evangowan.bsky.social!
🚨New Paper: "History of the Barents Sea Ice Sheet, MIS 11 to present" - Cofield & Darby (2025)
Utilized ice rafted debris + Fe-grains from a deep-sea Arctic sediment core to reconstruct ice movement/ timing for Barents Sea Ice Sheet through MIS 11 (~440 ka).
*Proxy explanation in🧵
(1/n) 🌊🧪
Utilized ice rafted debris + Fe-grains from a deep-sea Arctic sediment core to reconstruct ice movement/ timing for Barents Sea Ice Sheet through MIS 11 (~440 ka).
*Proxy explanation in🧵
(1/n) 🌊🧪
History of the Barents Sea Ice Sheet, MIS 11 to present
Understanding the history of large Arctic ice sheets is important in knowing the possibilities for future climate change and its impact on existing ic…
www.sciencedirect.com
November 10, 2025 at 2:37 PM
For those interested, here's some additional information about our paper (and our proxy) 🙂 Thanks again for sharing @evangowan.bsky.social!
"History of the Barents Sea Ice Sheet, MIS 11 to present"
Cofield & Darby, 2025
You can access our publication for FREE through 28 December 2025 (5/end) 🌊🧪
Cofield & Darby, 2025
You can access our publication for FREE through 28 December 2025 (5/end) 🌊🧪
authors.elsevier.com
November 10, 2025 at 2:34 PM
"History of the Barents Sea Ice Sheet, MIS 11 to present"
Cofield & Darby, 2025
You can access our publication for FREE through 28 December 2025 (5/end) 🌊🧪
Cofield & Darby, 2025
You can access our publication for FREE through 28 December 2025 (5/end) 🌊🧪
(4/n) Not included in the paper, but here's a quick overview of how we use the "chemical fingerprint" of individual Fe-grains as a tracker for ice movement from a circum-Arctic "source area" to the core site.
NOTE: I included a step-by-step explanation in the ALT TXT 🌊🧪
NOTE: I included a step-by-step explanation in the ALT TXT 🌊🧪
![Infograph starts on top Left:
1. Arctic climate has changed dramatically over time, aka- "paleoclimate".
2. During glacial periods, icebergs calve off glaciers and sea ice forms- carrying (or "rafting") sediment from their original location.
3. As ice circulates the Arctic, it's only exit [during glacials] is the Fram Strait. When it encounters *slightly warmer waters and starts melting, the sediment drops to the sea floor.
4. We collected a deep-sea sediment core in the "sweet spot" of sediment deposition, the Fram Strait.
5. Sediments are separated by size, then Fe-grains are magnetically separated. We use an electron microprobe to analyze a suite of elements in each Fe-grain, which provides a unique "chemical fingerprint".
6. These chemical fingerprints are matched to a robust database of circum-Arctic Fe-grain "source areas".
How does the proxy come together:
Now we know WHERE the grains came from. We also developed an age model to we can identify WHEN they were deposited. With this information we can select certain time frames and examine which geographic region (or "source areas") were actively dispersing ice and rafting sediments. Aka- we are reconstructing paleo-ice movement with Fe-grains. However, this is only one proxy and should be combined with several proxies and models for a comprehensive understanding of Arctic paleoclimate.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:dodtevapzpvqildhsdkltrz3/bafkreigwgrrubbljbeuzmz3v7jpa37r76k2fs7lqv3a3l7n6l5ncuvcoiu@jpeg)
November 10, 2025 at 2:34 PM
(4/n) Not included in the paper, but here's a quick overview of how we use the "chemical fingerprint" of individual Fe-grains as a tracker for ice movement from a circum-Arctic "source area" to the core site.
NOTE: I included a step-by-step explanation in the ALT TXT 🌊🧪
NOTE: I included a step-by-step explanation in the ALT TXT 🌊🧪
(3/n) Highlights:
- Comprehensive identification of Mass Ice Rafting Events
- Comparison to known models/ evidence for BSIS extent and timing
- BSIS may not have existed before MIS 6 (alternative processes that prohibited Fe-grain transport or melt out at core site from MIS 11 to 6!?) 🌊🧪
- Comprehensive identification of Mass Ice Rafting Events
- Comparison to known models/ evidence for BSIS extent and timing
- BSIS may not have existed before MIS 6 (alternative processes that prohibited Fe-grain transport or melt out at core site from MIS 11 to 6!?) 🌊🧪
November 10, 2025 at 2:34 PM
(3/n) Highlights:
- Comprehensive identification of Mass Ice Rafting Events
- Comparison to known models/ evidence for BSIS extent and timing
- BSIS may not have existed before MIS 6 (alternative processes that prohibited Fe-grain transport or melt out at core site from MIS 11 to 6!?) 🌊🧪
- Comprehensive identification of Mass Ice Rafting Events
- Comparison to known models/ evidence for BSIS extent and timing
- BSIS may not have existed before MIS 6 (alternative processes that prohibited Fe-grain transport or melt out at core site from MIS 11 to 6!?) 🌊🧪
(2/n) ⏳Arctic deep-sea sediment core age model:
Arctic deep-sea core age models are tricky! We extended our previous age model through MIS 11.
📍Yermak Plateau/ Fram Strait core: HLY0503-JPC22 (2/n) 🌊🧪
Arctic deep-sea core age models are tricky! We extended our previous age model through MIS 11.
📍Yermak Plateau/ Fram Strait core: HLY0503-JPC22 (2/n) 🌊🧪
November 10, 2025 at 2:34 PM
(2/n) ⏳Arctic deep-sea sediment core age model:
Arctic deep-sea core age models are tricky! We extended our previous age model through MIS 11.
📍Yermak Plateau/ Fram Strait core: HLY0503-JPC22 (2/n) 🌊🧪
Arctic deep-sea core age models are tricky! We extended our previous age model through MIS 11.
📍Yermak Plateau/ Fram Strait core: HLY0503-JPC22 (2/n) 🌊🧪
Thank you for sharing! Really excited for this paper.
November 10, 2025 at 12:38 PM
Thank you for sharing! Really excited for this paper.
Oooh! This could have some nice insights that run parallel to our new paper (accepted- posting shortly!). Our proxy for Arctic iceberg/ sea ice movement is ice rafted debris (sediments)- new pub constrains IRD events from Barents Sea Ice Sheet during glacial maxima (MIS11-1).
November 9, 2025 at 4:40 PM
Oooh! This could have some nice insights that run parallel to our new paper (accepted- posting shortly!). Our proxy for Arctic iceberg/ sea ice movement is ice rafted debris (sediments)- new pub constrains IRD events from Barents Sea Ice Sheet during glacial maxima (MIS11-1).
I’m sorry… there’s also a Margaritaville SPACESUIT 😳🤩
ISS Spacesuit
Web exclusive Spacesuit is to commemorate the "first of its kind" mission patch with the International Space Station National Lab x Margaritaville Patch. This Spacesuit comes with our ISS x Margaritav...
margaritavillestore.com
November 9, 2025 at 2:06 PM
I’m sorry… there’s also a Margaritaville SPACESUIT 😳🤩
“I have always been a believer in the notion that space exploration is in our DNA and is the source of so much technology that can make our lives on this planet better.”
-Jimmy Buffett. 🌴
-Jimmy Buffett. 🌴
November 9, 2025 at 2:00 PM
“I have always been a believer in the notion that space exploration is in our DNA and is the source of so much technology that can make our lives on this planet better.”
-Jimmy Buffett. 🌴
-Jimmy Buffett. 🌴
Sent a DM about your Polar Oceans Group. Thanks for developing these!!!
November 9, 2025 at 1:04 PM
Sent a DM about your Polar Oceans Group. Thanks for developing these!!!
Nice! Excited to see who was able to make it. Mavericks is always a bit temperamental, so it’s great to see some barrels 🏄🏻♀️ Looks like there’s >8m seas offshore feeding that energy.
November 8, 2025 at 4:04 PM
Nice! Excited to see who was able to make it. Mavericks is always a bit temperamental, so it’s great to see some barrels 🏄🏻♀️ Looks like there’s >8m seas offshore feeding that energy.
Ooooh 👀 Our paper reconstructing the Barents Sea Ice Sheet (MIS 11-1) is about to be published (IRD, so includes interpretation of sea ice). Excited to read through this one and see the reconstructions. Might help us answer some outstanding Qs for our next manuscript.
November 7, 2025 at 9:12 PM
Ooooh 👀 Our paper reconstructing the Barents Sea Ice Sheet (MIS 11-1) is about to be published (IRD, so includes interpretation of sea ice). Excited to read through this one and see the reconstructions. Might help us answer some outstanding Qs for our next manuscript.
Final USGS 2025 Critical Minerals List
U.S. Federal Register notice 11/07/2025 🌊🧪
U.S. Federal Register notice 11/07/2025 🌊🧪
Final 2025 List of Critical Minerals
Critical minerals are essential for national security, economic stability, and supply chain resilience because they underpin key industries, drive technological innovation, and support critical infras...
www.federalregister.gov
November 7, 2025 at 1:25 PM
Final USGS 2025 Critical Minerals List
U.S. Federal Register notice 11/07/2025 🌊🧪
U.S. Federal Register notice 11/07/2025 🌊🧪
Final USGS 2025 Critical Minerals List 🌊🧪
About the 2025 List of Critical Minerals
This page contains information about the 2025 List of Critical Minerals, including Frequently Asked Questions, related publications and more.
www.usgs.gov
November 7, 2025 at 1:25 PM
Final USGS 2025 Critical Minerals List 🌊🧪