Dr. Kim Hannula
@stressrelated.bsky.social
Retired structural geology professor and geoscience education researcher, living in the mountains. Fan of blueschists, contact metamorphism, shear zones, faults, deformation bands, spatial thinking, strategies to make teaching more inclusive. She/her/hers
Durango, Colorado 7:16 Mountain Standard Time
November 12, 2025 at 3:51 AM
Durango, Colorado 7:16 Mountain Standard Time
Reposted by Dr. Kim Hannula
Submit them to Aurorasaurus!!! They're an NSF funded project out of University of New Mexico that takes crowdsourced aurora observations for research purposes:
www.aurorasaurus.org
www.aurorasaurus.org
Aurorasaurus - Reporting Auroras from the Ground Up
Friends, see my real-time #aurora report on the aurorasaurus.org map! Follow us on www.facebook.com/aurorasaurus.org. Reporting #northernlights and #citizenscience from the ground up since 2012!
www.aurorasaurus.org
November 12, 2025 at 3:25 AM
Submit them to Aurorasaurus!!! They're an NSF funded project out of University of New Mexico that takes crowdsourced aurora observations for research purposes:
www.aurorasaurus.org
www.aurorasaurus.org
Oh, I hope the Plateau Fence Lizard does this too.
November 12, 2025 at 3:23 AM
Oh, I hope the Plateau Fence Lizard does this too.
We could even see moving sheets with just our eyes.
November 12, 2025 at 3:00 AM
We could even see moving sheets with just our eyes.
*Keweenaw. Dang repeated misspelling.
November 11, 2025 at 12:00 AM
*Keweenaw. Dang repeated misspelling.
Dang, my spelling is the worst. Sorry. ( I can't fix the thread now.)
November 10, 2025 at 11:59 PM
Dang, my spelling is the worst. Sorry. ( I can't fix the thread now.)
The Keeweenaw Peninsula is part of a failed rift. (It continues to the south, but it gets buried by sedimentary rock.)
November 10, 2025 at 11:58 PM
The Keeweenaw Peninsula is part of a failed rift. (It continues to the south, but it gets buried by sedimentary rock.)
When continents pull apart, there tend to be a lot of volcanoes that erupt basalt. Sometimes, the continents pull all the way apart and a new ocean basin forms. But sometimes, the rift fails, and we're left with a long area with lots of basalt and related rock.
November 10, 2025 at 11:56 PM
When continents pull apart, there tend to be a lot of volcanoes that erupt basalt. Sometimes, the continents pull all the way apart and a new ocean basin forms. But sometimes, the rift fails, and we're left with a long area with lots of basalt and related rock.
The Keeweenaw Peninsula (and its copper) has a different relationship to oceans. Around a billion years ago*, the continent that includes today's North American tried to pull apart in what we call the Midcontinental Rift.
*Midwesterners, please forgive the oversimplification.
*Midwesterners, please forgive the oversimplification.
November 10, 2025 at 11:54 PM
The Keeweenaw Peninsula (and its copper) has a different relationship to oceans. Around a billion years ago*, the continent that includes today's North American tried to pull apart in what we call the Midcontinental Rift.
*Midwesterners, please forgive the oversimplification.
*Midwesterners, please forgive the oversimplification.
So ophiolites are a classic piece of evidence that continents collided with something.
Other competitors in past mineral cups are associated with ophiolites - the serpentine minerals, in particular, are connected to ophiolites.
Other competitors in past mineral cups are associated with ophiolites - the serpentine minerals, in particular, are connected to ophiolites.
November 10, 2025 at 11:51 PM
So ophiolites are a classic piece of evidence that continents collided with something.
Other competitors in past mineral cups are associated with ophiolites - the serpentine minerals, in particular, are connected to ophiolites.
Other competitors in past mineral cups are associated with ophiolites - the serpentine minerals, in particular, are connected to ophiolites.
When continents get dragged into subduction zones, they don't go down as easily as oceanic crust and mantle does. So bits of the top plate - including pieces of oceanic (or oceanic-like) crust and mantle get stuck on top of them.
November 10, 2025 at 11:49 PM
When continents get dragged into subduction zones, they don't go down as easily as oceanic crust and mantle does. So bits of the top plate - including pieces of oceanic (or oceanic-like) crust and mantle get stuck on top of them.
Tectonic plates move toward one another at subduction zones. One piece of oceanic crust plus mantle dives beneath another, and continents get dragged along with them.
*I know this is way oversimplified.
*I know this is way oversimplified.
November 10, 2025 at 11:47 PM
Tectonic plates move toward one another at subduction zones. One piece of oceanic crust plus mantle dives beneath another, and continents get dragged along with them.
*I know this is way oversimplified.
*I know this is way oversimplified.
The textbook story of ophiolites is that they are pieces of oceanic crust (though a lot of them might be more complicated). But they are found on continents. So there's more to the story.
November 10, 2025 at 11:45 PM
The textbook story of ophiolites is that they are pieces of oceanic crust (though a lot of them might be more complicated). But they are found on continents. So there's more to the story.
The Troodos ophiolite is famous having a great sequence of the rocks - most ophiolites have some pieces, but not all.
Recommended reading: Assembling California by John McPhee has lots of great stuff about ophiolites, their role in developing the theory of plate tectonics, and the copper on Cyprus.
Recommended reading: Assembling California by John McPhee has lots of great stuff about ophiolites, their role in developing the theory of plate tectonics, and the copper on Cyprus.
November 10, 2025 at 11:44 PM
The Troodos ophiolite is famous having a great sequence of the rocks - most ophiolites have some pieces, but not all.
Recommended reading: Assembling California by John McPhee has lots of great stuff about ophiolites, their role in developing the theory of plate tectonics, and the copper on Cyprus.
Recommended reading: Assembling California by John McPhee has lots of great stuff about ophiolites, their role in developing the theory of plate tectonics, and the copper on Cyprus.
Side note: "sheeted dikes" are weird, because they have smaller crystals (typical of fast cooling) on one side, but not the other. Most magma-filled cracks cool from both sides. But if cracks form, fill with magma, cool, and crack again, you can get "sheeted" dikes.
November 10, 2025 at 11:41 PM
Side note: "sheeted dikes" are weird, because they have smaller crystals (typical of fast cooling) on one side, but not the other. Most magma-filled cracks cool from both sides. But if cracks form, fill with magma, cool, and crack again, you can get "sheeted" dikes.
Sure.
Cyprus is famous in geology for the Troodos ophiolite. An ophiolite is a sequence of rocks that is similar to the ideal sequence of the ocean floor: pillow basalts above "sheeted dikes" (vertical cracks filled with magma) above gabbro above mantle-ish rocks.
Cyprus is famous in geology for the Troodos ophiolite. An ophiolite is a sequence of rocks that is similar to the ideal sequence of the ocean floor: pillow basalts above "sheeted dikes" (vertical cracks filled with magma) above gabbro above mantle-ish rocks.
November 10, 2025 at 11:39 PM
Sure.
Cyprus is famous in geology for the Troodos ophiolite. An ophiolite is a sequence of rocks that is similar to the ideal sequence of the ocean floor: pillow basalts above "sheeted dikes" (vertical cracks filled with magma) above gabbro above mantle-ish rocks.
Cyprus is famous in geology for the Troodos ophiolite. An ophiolite is a sequence of rocks that is similar to the ideal sequence of the ocean floor: pillow basalts above "sheeted dikes" (vertical cracks filled with magma) above gabbro above mantle-ish rocks.
Oh, ok. I'm curious which boats go through the Portage Canal?
(My dad's family lived in the Hancock-Houghton area, and when I was little I was fascinated by the bridge and the complicated way it raised in the middle to let boats through.)
(My dad's family lived in the Hancock-Houghton area, and when I was little I was fascinated by the bridge and the complicated way it raised in the middle to let boats through.)
November 10, 2025 at 8:02 PM
Oh, ok. I'm curious which boats go through the Portage Canal?
(My dad's family lived in the Hancock-Houghton area, and when I was little I was fascinated by the bridge and the complicated way it raised in the middle to let boats through.)
(My dad's family lived in the Hancock-Houghton area, and when I was little I was fascinated by the bridge and the complicated way it raised in the middle to let boats through.)
I think it's cool how copper connects to tectonics - a failed rift in Michigan, ocean floor stranded by convergent tectonics in Cyprus - and how that tectonics connects to human use of metals.
November 10, 2025 at 7:16 PM
I think it's cool how copper connects to tectonics - a failed rift in Michigan, ocean floor stranded by convergent tectonics in Cyprus - and how that tectonics connects to human use of metals.
The copper in the Troodos Ophiolite on Cyprus is cool, too.
November 10, 2025 at 7:11 PM
The copper in the Troodos Ophiolite on Cyprus is cool, too.
Copper Harbor, on the Keeweenaw Penisula of Michigan, is near the spot where the Edmund Fitzgerald first faced bad weather. If only it had taken shelter in the Copper Country!
November 10, 2025 at 7:11 PM
Copper Harbor, on the Keeweenaw Penisula of Michigan, is near the spot where the Edmund Fitzgerald first faced bad weather. If only it had taken shelter in the Copper Country!