Tim Demko
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timdemko.xyz
Tim Demko
@timdemko.xyz
2.8K followers 4.7K following 730 posts
Geologist interested in the energy transition, bicycling, and public service

https://bio.link/timdemko

https://orcid.org/0000-0002-9125-0907

https://www.semanticscholar.org/author/Timothy-Michael-Demko/15743754
Posts Replies Media Videos
Reposted by Tim Demko
tomsharperocks.bsky.social
8 January 1823: newspapers report on the first donation to Bristol Institution's new museum – a fine Ichthyosaurus communis from Lyme Regis, purchased for £50 from #MaryAnning by 9 of the Institution's members, including Henry De la Beche and William Conybeare who described Ichthyosaurus in 1821.
Left, portrait of Mary Anning in a green cloak and straw bonnet, holding a hammer and with a basket over her arm; right top, extract from a newspaper of 8 January 1823 'BRISTOL PHILOSOPHICAL INSTITUTION By way of beginning in the formation of a Museum, a beautiful specimen of organic remains, cut from the face of a rock at Lyme, in Dorsetshire, was presented to this Institution. It is the skeleton of a wonderful fish, between the porpoise and the dolphin, having paddles or fins (it is not determined which) instead of feet. It is about five feet long, and is, perhaps, the best and most perfect specimen the kind in the kingdom'; right centre, extract from a Bristol Institution report listing the donors of 'A fine Skeleton of Ichthyosaurus Communis, from the Lias at Lyme, Dorsetshire'; right bottom, the Bristol Institution's building on Park Street.
January 8, 2026 at 2:28 PM
Reposted by Tim Demko
lockwooddewitt.bsky.social
I've felt the exact same way, from thin sections, to outcrops, to satellite images, and satellite images from whole other planets. And it makes me impossibly sad that so many never have a chance to see such wonders. ⚒️
maracox.bsky.social Mara Cox @maracox.bsky.social · 16h
Galaxies and stories tucked away inside a rock. Geology feels like a tiny peep hole into secret land. It makes me think about snorkeling and feeling like you're spying on another world. What a privilege it is to be alive and to see the world on so many beautiful scales.
January 8, 2026 at 6:55 PM
Reposted by Tim Demko
maracox.bsky.social
Galaxies and stories tucked away inside a rock. Geology feels like a tiny peep hole into secret land. It makes me think about snorkeling and feeling like you're spying on another world. What a privilege it is to be alive and to see the world on so many beautiful scales.
January 8, 2026 at 6:50 PM
Reposted by Tim Demko
paleojim.bsky.social
Susannah Maidmen presentation next week (Tuesday 13 January 5 -7 PM GT & 10-12 AM MT) online, via Zoom.
"Bizarre Dinosaurs from the Middle Jurassic of Morocco: Implications for Armoured Dinosaur Evolution". www.bilnas.org/event/bizarr...
Register in advance. us02web.zoom.us/webinar/regi...
Bizarre Dinosaurs from the Middle Jurassic of Morocco: Implications for Armoured Dinosaur Evolution by Susannah Maidment
The Middle Jurassic is a critical time in the evolution of the dinosaurs because it witnessed the radiation of many groups, giving rise to a diversity of familiar forms such as the plated stegosaurs a...
www.bilnas.org
January 8, 2026 at 5:13 PM
Reposted by Tim Demko
allochthonous.bsky.social
“after magma ocean crystallization, bridgmanite may have stored an ocean’s worth of water in the lower mantle”
hlee.bsky.social Howard Lee @hlee.bsky.social · 23h
Experiments point to early Earth's mantle retaining a LOT of water through the magma ocean stage and into crystallization ⚒️
www.science.org/doi/10.1126/...
Deep mantle clues to Earth’s watery beginning
Minerals in the lower mantle may store more water than previously estimated
www.science.org
January 8, 2026 at 1:42 PM
Reposted by Tim Demko
earthscope.org
The NSF National Geophysical Facility will be expanding support for near-surface geophysics. Your input can help shape future efforts for research and teaching with near-surface geophysics!

Please take a few minutes to complete this survey ➡️ https://loom.ly/tVEZXlE
Illustration of a person pushing a ground-penetrating radar cart across grass, with subsurface waves shown belowground. Text reads “Near-Surface Geophysics Support” and “Community input needed!” with NSF and National Geophysical Facility (operated by EarthScope) logos at the bottom.
January 7, 2026 at 7:20 PM
timdemko.xyz
I rarely post photos of myself, especially in uniform, but the events of today are clashing mightily with the stupendous day I had in the field yesterday. Here I am, mid geologizing mode, waxing eloquently about some fascinating details of the 1.7 byo schist in the background. Must remember...
A photo of a geologist standing on an outcrop, pointing to a cliff face in the background. He is holding a map board, there are trees, and clouds in a brilliant Arizona blue sky. It was a good. No, great.
January 8, 2026 at 4:57 AM
Reposted by Tim Demko
seismic-shrimp.bsky.social
Getting back into the swing of ungulates after a bit, here are four rhinos: Parvorhinus, Uintaceras, Megacanodon, Aprotodon qiui #paleoart #sciart
January 8, 2026 at 12:44 AM
Reposted by Tim Demko
eartharchives.bsky.social
A 1.78-million-year-old partial elephant skeleton found in Tanzania associated with stone tools may represent the oldest known evidence of butchery of the giant herbivores

www.newscientist.com/article/2510...

#fossils #paleontology
January 8, 2026 at 1:21 AM
Reposted by Tim Demko
smmnh.bsky.social
A flower beetle in baltic amber. We hope to raise money for a museum microscope so kids can examine insect specimens like this one!
A flower beetle in baltic amber. We hope to raise money for a museum microscope so kids can examine insect specimens like this one!
January 7, 2026 at 7:59 PM
Reposted by Tim Demko
bedform.org
Niche geology-potter content… a little three piece columnar basalt sculpture. Wild clay with a bunch of coarse nepheline syenite from Arkansas (late Cretaceous) wedged in. Hopefully the feldspars will melt out a bit in the wood kiln. They’re manganese bearing so I’m hoping for some dark streaks
January 7, 2026 at 6:49 PM
Reposted by Tim Demko
sketchy-raptor.bsky.social
New material of Ajkaceratops cements its identity as a ceratopsian, but adds a new wrinkle. It turns out that many european ornithischians previously classified as iguanodontians may actually be ceratopsians! New paper by @tweetisaurus.bsky.social et al., that I provided art for (link in reply).
January 7, 2026 at 5:44 PM
Reposted by Tim Demko
tweetisaurus.bsky.social
Out in @nature.com today, we shake up the ornithischian family tree. Remember those weird Late Cretaceous iguanodontians, the rhabdodontids? Well they're weird because they aren't iguanodontians. They're ceratopsians. Well, at least some of them are... www.nature.com/articles/s41...
A hidden diversity of ceratopsian dinosaurs in Late Cretaceous Europe - Nature
New results indicate that rhabdodontids and the previously described Ajkaceratops are actually distinctive European ceratopsians, a group better known from Asia and North America.
www.nature.com
January 7, 2026 at 4:57 PM
Reposted by Tim Demko
albertonykus.bsky.social
A look back on every new dinosaur named in 2025: new-dinosaurs.tumblr.com/post/8048376... Which ones are your favorites? 🧪🪶 (📷Chinzorig et al., Hechenleitner et al., Zissoudisctrucker, Morais et al.)
Fossilized skeleton and select bones of Zavacephale rinpoche, a two-legged dinosaur with a thick, domed skull. Fossilized skeleton and select bones of Huayracursor jaguensis, a two-legged, long-necked dinosaur. Skeleton of Nanotyrannus lethaeus on display at a museum. It is a two-legged, meat-eating dinosaur resembling a smaller and more slender Tyrannosaurus rex. Four photographs of Tinamus resonans, a ground-dwelling, somewhat partridge-like bird on a forest floor. The bird is mostly brownish in color, with a dark gray "mask" over its eyes and the top of its head.
January 7, 2026 at 7:10 PM
Reposted by Tim Demko
paleojim.bsky.social
I have been anxiously waiting for this paper on European ceratopsians! Congratulations all!
www.nature.com/articles/s41... @paleontologizing.bsky.social @utahpaleo-ufop.bsky.social @jeremybroberts.bsky.social @tweetisaurus.bsky.social @richardjbutler.bsky.social @societyofvertpaleo.bsky.social
A hidden diversity of ceratopsian dinosaurs in Late Cretaceous Europe - Nature
New results indicate that rhabdodontids and the previously described Ajkaceratops are actually distinctive European ceratopsians, a group better known from Asia and North America.
www.nature.com
January 7, 2026 at 8:20 PM
Reposted by Tim Demko
arctomet.bsky.social
Details about the mistreatment of the paleontology program at Carthage College in Thomas Carr's own words:

www.wgtd.org/playlist/mor...
MS - Dr. Thomas Carr
Paleontologist
www.wgtd.org
January 7, 2026 at 8:14 PM
Reposted by Tim Demko
exeterunispeccoll.bsky.social
This beautiful colour plate shows rock formations on the East Devon coast caused by landslips between December 1839 & February 1840. Corn grew on the rocks that had fallen from the fields above, attracting fascinated visitors.

📷 Reserve 554.235 DAW/XX (1840)

#OldRockDay #Geology #RareBooks #Devon
Colour illustration of rock formations with wheat growing on them, entitled 'View in the Great Chasm of Axmouth Landslip.' Looking Westward. Reaping the Wheat 25th August 1840.' The illustration includes depictions of people in 19th century clothing.
January 7, 2026 at 10:03 AM
Reposted by Tim Demko
ichnologist.bsky.social
Diprotodon and Genyornis from the Pleistocene of Australia will return in AVENGERS: DOOMSDAY.
Skeletal mounts of the world's largest marsupial, Diprotodon, and the large flightless bird Genyornis, both from the Pleistocene Epoch of Australia; mounts on display at Museum Victoria in Melbourne, Australia.
January 7, 2026 at 10:35 AM
Reposted by Tim Demko
eartharchives.bsky.social
Scientists are uncovering dinosaur mummies in Wyoming that reveal what these animals truly looked like in life.

www.iflscience.com/wyomings-mum...

#fossils #paleontology
January 7, 2026 at 11:19 AM
Reposted by Tim Demko
clarkeocrinus.bsky.social
Why not. Here's another fossil on a long Monday.

A juvenile Platycrinites from the Mississippian Mont Eagle formation of Alabama.
January 5, 2026 at 8:52 PM
Reposted by Tim Demko
swais2c.bsky.social
We have successfully drilled 200 metres of sediment core from beneath the ice sheet at Crary Ice Rise! The pipe is still spinning - with a bit of time up our sleeve, we’re not stopping drilling yet, as we continue to drill back through the geological archive hidden beneath the ice. 📷 Ana Tovey
January 6, 2026 at 1:20 AM
Reposted by Tim Demko
geology.bsky.social
Amid all the other uproar, I have a new blog post out.
Ore from the former Alma Mine
The Alma pyrite mine and its neighbors dug into the hillsides of Leona Heights from the 1890s to the 1930s. The mineshafts have been covered up over the century since, so the fabulous veins of soli…
oaklandgeology.com
January 5, 2026 at 11:42 PM
Reposted by Tim Demko
hellyeahcorks.bsky.social
So exciting!! Tanya is an amazing person (I was SO fortunate to have her for plate tectonics during my time at UCSB). Her stories about going to sea before women were accepted on ships are 🤯 and she's an inspiration for seagoing women scientists.
highcountrynews.org High Country News @highcountrynews.org · 3d
The discovery that the continents are in continuous motion is fairly recent—dating back only to the late 1960s — and one woman was responsible for decoding what it meant for California and much of the West Coast.

buff.ly/2vAwspH
Drifters and the introduction of plate tectonics - High Country News
How the San Andreas fault and Tanya Atwater’s theory changed geology.
www.hcn.org
January 5, 2026 at 8:36 PM
Reposted by Tim Demko
extinctmonsters.bsky.social
You know what else bogs provide? Hundreds of Irish elk skeletons.
Giant deer skeleton mounted with head down, showing off antlers Giant deer in resting pose Giant deer skeleton mounted with head turned to the right Giant deer skeleton with head turned right, facing camera
January 6, 2026 at 3:24 AM
Reposted by Tim Demko
mosasaurologist.bsky.social
Happy #MosasaurMonday from our newest Tylosaurus, Nolan. I'm still working on figuring out what species this one is, but more skull bones are being prepared every day.

This is most of the right lower jaw, just missing the angular. 3 feet long, which is quite large for the lower Niobrara 🧪
A long straight and toothy lower jaw on a red draped table
January 5, 2026 at 8:06 PM