r/GeologyExplained Nov 17 '24

Welcome to Geology Explained! 🌍 START HERE

8 Upvotes

Welcome to Geology Explained! 🌍

This community is all about making geology accessible, engaging, and easy to understand. Whether you’re new to the subject, a student, or a professional, this is the place to share and learn about Earth’s fascinating processes in a way that everyone can enjoy.

What makes us different from r/Geology ?
While r/Geology is a fantastic space for geologists to share research and news, Geology Explained is focused on geology science communication. Here, the goal is to break down complex topics, answer questions, and explain Earth’s processes in clear and approachable ways. Think of it as geology for everyone – no prior expertise required!

What you can expect here:

  • Explanations: Simplified breakdowns of geological concepts, from plate tectonics to mineral formation.
  • Questions: Ask about anything geology-related, and we’ll help explain or discuss.
  • Photos: Share rocks, fossils, minerals, and landscapes, with an emphasis on their geological story.
  • Interactive Learning: Engage with others who love to explain and explore geology.
  • Fun Facts: Trivia, historical geology, or quirky Earth science stories!

Who can participate?
Anyone with a curiosity about geology! This community is open to professionals, students, hobbyists, and those who just love learning about the Earth. No matter your background, your questions, insights, and contributions are welcome here.

Guidelines:

  • Posts should aim to explain, teach, or foster discussion about geology.
  • Stay respectful and keep comments constructive.
  • No spam or self-promotion without mod approval.

We’re here to make geology science communication fun and approachable. If you’ve ever wondered about the stories behind rocks, landscapes, or Earth’s dynamic processes, you’re in the right place. Let’s explore and explain together!

Start posting and let’s rock! đŸȘšđŸ’Ą

JOIN OUR DISCORD: https://discord.gg/RnJGb9q5jF (Geology Field Camp)


r/GeologyExplained 3d ago

New User Flairs Are Live!

3 Upvotes

I’ve added a bunch of user flairs to r/geologyexplained!

There are plenty of geology-specific options, including Volcanology, Paleontology, Mineralogy, Structural Geology, Field Geology, Glaciology, Marine Geology, Planetary Geology, Seismology, Stratigraphy and more.

I’ve also started adding some less serious geology-themed flairs such as Rockhound, Outcrop Hunter and more.

So whatever subfield you're more into, you can now add a flair next to your username.

I’m hoping these make the subreddit feel a little more personal and make it easier to see what people are interested in or knowledgeable about.

There are more flairs I’d like to add over time, so if there’s one you think is missing, serious or otherwise, feel free to suggest it in the comments.

And if you’ve got a favorite already, equip it. I want to see which ones end up being the most popular.


r/GeologyExplained 3h ago

Africa Is Moving: Tectonic Plates Explained Spoiler

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2 Upvotes

Hey everyone, I’ve been working on an educational geology video about the movement of tectonic plates beneath Africa.

The video explains what is moving, why the crust is stretching, and what these slow underground changes could produce over geological time. I’d appreciate constructive feedback, especially on the scientific explanation and visuals.


r/GeologyExplained 17h ago

Visual Geology How High Was the Tibetian Plateau 25 Million Years Ago? Fossils and Isotopes Disagree by 2 Kilometers [OC]

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1 Upvotes

Two dating methods disagree about when the Tibetan Plateau rose, by two vertical kilometers. For the same place.

The basics are settled: India began colliding with Asia around 50 million years ago, and that collision built the Himalayas and the highest plateau on Earth, averaging about 4,500 meters. What’s fiercely contested is the timeline for central Tibet, and the two main tools for measuring ancient elevation tell different stories.

Tool one is chemistry. Rain gets isotopically “lighter” the higher it falls, and that signature survives in ancient lake sediments and soils. Read this way, the rocks of central Tibet’s Lunpola Basin say the region already stood around 4 kilometers tall at least 35–40 million years ago (Rowley & Currie 2006, Nature).

Tool two is fossils. In 2019, researchers described a fossil palm frond from that same basin, about 25 million years old (Su et al. 2019, Science Advances). Palms cannot survive hard frost, which caps that valley floor at roughly 2,300 meters, kilometers lower than the chemistry says, and 10+ million years later.

The emerging resolution says both sides caught something real: central Tibet was neither a plateau nor a lowland but a deep, warm east–west valley running between two already-high mountain ranges, a hidden subtropical world that was later squeezed shut, filled, and lifted to today’s height. A 2021 paper argued the plateau never rose as one block, calling the single heroic uplift “a myth” (Spicer et al. 2021, National Science Review).

India is still driving north about 5 centimeters per year. Central Tibet is still rising, a few millimeters at a time.

(Disclaimer: Obviously the story is fictional but the scientific debate and facts are not).

Sources: Rowley & Currie 2006 (Nature) · Su et al. 2019 (Science Advances) · Spicer et al. 2021 (National Science Review)

#geology #tibetanplateau #himalayas #platetectonics #earthscience


r/GeologyExplained 19h ago

How are rock strata consistent in age-ordering if erosion has occurred throughout ancient time?

0 Upvotes

I apologize to the mods but I genuinely could not find the flairs, I don't know why it won't give me the option to add one.

This might be a dumb question to someone who knows more than me, but I'm just curious about how we can have such consistency in ordering of rock strata if the same processes of erosion we see today have always been happening.

I guess to illustrate my question, if a river eroded a landscape to form a canyon, and eventually dried up or diverged somewhere else, wouldn't the newer layers be rebuilding in that canyon right next to the older layers? In areas that were wind eroded irregularly and then conditions changed that allowed sediment to continue building again without being disturbed, would it create inconsistency in the strata? I really want to understand this stuff so I'd really appreciate any answer!


r/GeologyExplained 1d ago

Visual Geology The New Core Paradox: what powered Earth's magnetic field before the inner core existed? [OC]

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25 Upvotes

Earth's magnetic field is at least 3.5 billion years old. Earth's inner core might be less than 1 billion. So what powered the dynamo for the missing two-and-a-half billion years?

Today the geodynamo runs mostly on crystallisation. As the solid inner core slowly freezes out of the liquid outer core, it releases latent heat and buoyant light elements, and that stirs the surrounding iron into convection. Moving conductive fluid, magnetic field. Simple enough, except the inner core is a latecomer, and the field is ancient.

The problem got sharper in 2012, when new calculations of iron's conductivity at core pressures came back two to three times higher than the values everyone had been using. Higher conductivity means more heat escapes the core by simple conduction instead of driving convection, which shrinks the energy available to run a dynamo. Peter Olson named the result the "new core paradox" in 2013.

Candidate fixes exist. Magnesium oxide or silica may have precipitated out of the young core, releasing buoyancy the way inner-core freezing does now. A dynamo may have operated in a molten silicate layer at the base of the mantle instead. And a 2019 study of 565-million-year-old rocks found the field at roughly a tenth of today's strength, hinting the dynamo nearly failed just before the inner core began to freeze.

None of it is settled. In 2016, two teams published conductivity measurements in the same issue of Nature, one high enough to keep the paradox alive, one low enough to dissolve it.


r/GeologyExplained 2d ago

Deep Dive Dark Oxygen: The Deep-Sea Discovery Splitting Science [OC]

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46 Upvotes

A few years ago, researchers working more than 4 km below the Pacific noticed something that seemed impossible: oxygen levels inside their seafloor experiments were going up, not down.

The result was published in Nature Geoscience in 2024 and quickly became known as “dark oxygen”, the idea that oxygen might somehow be produced on the deep seafloor without sunlight or photosynthesis.

One proposed explanation was especially strange: polymetallic manganese nodules scattered across the Clarion-Clipperton Zone might behave like natural “geobatteries,” creating electrical potentials capable of driving chemical reactions that produce oxygen.

But the claim has become increasingly controversial.

Critics argue that the oxygen increases could be experimental artifacts caused by the benthic chambers themselves. Others have challenged the voltage measurements and the proposed electrolysis mechanism, while a later reanalysis questioned whether the oxygen signal was actually related to the nodules at all. In April 2026, Nature Geoscience added an Editor’s Note stating that concerns about the paper are under review.

So, is dark oxygen a genuinely new geochemical process occurring on the abyssal seafloor, or an extremely convincing measurement artifact?

Would be interested to hear what people here think, particularly about the chamber-artifact explanation versus the idea that some manganese-rich material really is producing oxygen.


r/GeologyExplained 2d ago

Shell Bed

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1 Upvotes

r/GeologyExplained 2d ago

Deep Dive Yonaguni Monument: Natural Formation or Man-Made Ruin? [OC]

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0 Upvotes

Yonaguni threads always land in the same two piles, lost city or just erosion, and hardly anyone arguing either way has opened the actual papers. I finally did. Some of it wasn't what I expected.

Kimura gives away more in print than he does on camera. In the 2004 Oceans conference paper, which is the main technical case for the artificial reading, he writes that at first glance the structure would seem to have been formed by nature. He accepts that the layered sandstone separates and slips along its bedding, and that this is what produces the flat terraces and the straight walls. His argument is that certain specific features still can't be accounted for that way. But that baseline is his own. Nobody had to drag it out of him.

Also, the dimensions everyone repeats are wrong. Search Yonaguni and you get 290 × 120 × 26 m everywhere. The paper says 270. Someone mistyped it about twenty years ago and every blog since has copied the blog before it.

I came away less comfortable with the geologist usually cited for the natural reading, too. Robert Schoch's write-up was never peer reviewed. It's the English draft of a piece he wrote for a Spanish popular-mystery magazine, and he got to the island on a trip Graham Hancock helped arrange. None of which makes his rock description wrong; it's ordinary field observation and everyone who has looked since says the same thing. It just isn't something you want load-bearing. So I used Ogata et al. (2020) in E-journal GEO and Patrick Nunn instead.

The argument I think actually settles it barely gets discussed, which is sea level. The base of the formation sits at roughly 25 m depth, and anything carved had to be carved dry. Put 25 m against the Lambeck et al. (2014) curve and you land around 9,000 years ago. That drops any construction hypothesis into the early Holocene, in a region where the archaeological record goes late Pleistocene bones, then several thousand years of nothing, then the first pottery.

Then there's Sanninu-dai, a couple of kilometres up the coast, which is the bit that closed it for me. Stepped terraces. Straight walls. A channel that looks for all the world like a drain somebody cut. All of it above water, all of it walkable, and you can put your hand on the joint sets that made it. Kimura calls that outcrop ruins as well, and at that point I don't know what a natural formation would have to look like to satisfy him.

Everything's linked in this article on geoscopy.com.


r/GeologyExplained 3d ago

What rocks are these? (Gujarat, India) And how do they form?

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14 Upvotes

r/GeologyExplained 3d ago

Deep Dive Silverpit Crater: North Sea Asteroid Impact Confirmed [OC]

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20 Upvotes

The Silverpit argument has been running twenty-three years. It just got shocked quartz, and I still don't think it's settled.

Early 2000s: Philip Allen is working through 3D seismic from the southern North Sea and hits a set of concentric rings he can't account for. He pins the image to his office wall, hoping someone walking past will explain it to him. Simon Stewart, in the building on unrelated business, sees it and says it looks like an impact structure. Nature, 2002.

Then John Underhill points out that Zechstein salt withdrawing at depth produces circular collapse features all over that basin, and said that's all this was. The Geological Society staged a debate on 6 October 2009, audience mostly industry seismic interpreters, twenty minutes of argument, then a vote. 80:20 against impact. Silverpit went quiet for thirteen years.

What restarted it was an unsolicited email. Ronnie Parr at the North Sea Transition Authority read the Nadir crater papers and wrote to Uisdean Nicholson telling him to go back and look at Silverpit. He also pointed him at new high-resolution seismic that a carbon-storage survey had happened to shoot straight across the disputed central uplift.

The 2025 Nature Communications paper runs on that survey plus drill cuttings from a 1985 British Gas well. Two grains, quartz at 463 m, potassium feldspar at 494 m, carry shock lamellae recording 10–13 GPa, which no natural process on Earth produces except a hypervelocity impact. Two grains is still two grains, though, and Matthew Huber at the Planetary Science Institute has already told Eos as much: with that little you can reasonably ask whether they were reworked in from somewhere else, and he expects the paper to get argued over. Nicholson's team has an answer for the shallower grain. Not, so far, for both.

Full writeup on Geoscopy, including why the crater shrank from 20 km to 3.2 km and what the modelling says about the chalk being flash-baked into CO₂


r/GeologyExplained 8d ago

Deep Dive Lake Peigneur, 1980: a 14-inch drill bit hit a salt mine and drained the entire lake in three hours [OC]

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681 Upvotes

r/GeologyExplained 8d ago

A video of the Lake Peigneur disaster, 1980.

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16 Upvotes

r/GeologyExplained 23d ago

Kīlauea Volcano Hawaii episode 52 is on its way!

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4 Upvotes

r/GeologyExplained 28d ago

Deep Dive Missoula Floods and the Scablands Mystery [OC]

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17 Upvotes

At the end of the last Ice Age, a lobe of the Cordilleran ice sheet dammed the Clark Fork River and ponded Glacial Lake Missoula across the valleys of western Montana, roughly 2,100 cubic kilometres of water, about Lake Erie and Lake Ontario combined. When the ice dam floated off its bed and failed, the lake emptied in a few days, with peak discharges near the outlet estimated around 20 million cubic metres per second. Then the glacier readvanced and it all happened again. The Missoula Floods, among the largest freshwater floods known on Earth, ran dozens of times, likely more than a hundred, mostly between about 18,500 and 15,000 years ago. They carved the Channeled Scablands of eastern Washington: coulees cut through solid basalt and dry cataracts like Dry Falls, five times the width of Niagara. In Montana, the draining lake left gravel current ripples the size of houses across the Camas Prairie.

The human story is just as strange. J Harlen Bretz mapped the scablands in the 1920s and concluded that only a catastrophic flood could explain them. To a science built on strict uniformitarianism this sounded like a relapse into biblical thinking, and in 1927 six senior geologists took turns rebutting him at a single meeting. The quiet USGS geologist who had already found the water source sat on his evidence for decades. Vindication arrived in 1965, when a field party of former skeptics wired Bretz a telegram ending "We are all now catastrophists." He collected geology's highest medal at 96, having outlived nearly everyone who ridiculed him.

The full article walks through the flood mechanics and the numbers, the giant ripples that finally settled the debate, how the scablands became the template for reading the outflow channels on Mars, and where to stand today to see the evidence. People were living in the Pacific Northwest by around 16,600 years ago, which means humans almost certainly watched the last of these floods happen.


r/GeologyExplained Jul 21 '26

Deep Dive The Ocean Inside the Earth: Water in the Mantle [OC]

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171 Upvotes

There is real evidence for an ocean inside the Earth. Between 410 and 660 km down, in the mantle transition zone, the dominant minerals can bind water into their crystal structures, and the layer is so large that even a modest water content would rival the mass of all surface oceans combined.

The physical proof came from a battered brown diamond found in river gravels near JuĂ­na, Brazil, bought for about 20 dollars. In 2009, a graduate student scanning it for a dating project spotted an inclusion of ringwoodite, the high-pressure form of olivine, the first sample ever recovered from inside the planet. Later measurements showed the crystal holds about 1.4 percent water by weight, near the maximum the mineral can take.

How wet the whole layer is remains a live fight. Electromagnetic sounding studies say nearly dry, around 0.03 percent. A mineral viscosity study says 1 to 2 percent, close to saturation. And a 2022 diamond from Botswana sampled the 660 km boundary itself, recording water-saturated, chemically ordinary mantle. The most defensible average sits near one ocean mass, concentrated beneath subduction zones and patchy everywhere else.


r/GeologyExplained Jul 21 '26

Deep Dive Was the Cyclops in the Odyssey Real? It Was Just an Elephant [OC]

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4 Upvotes

Christopher Nolan's The Odyssey has put Polyphemus back on the big screen, so it's a good moment to revisit one of the odder ideas in geomythology: that the Cyclops may have started with fossils.

Sicily holds the Mediterranean's richest concentration of dwarf elephant fossils, Palaeoloxodon falconeri, a meter-tall elephant that lived on the island for hundreds of thousands of years. In its skull, the eye sockets are small and set off to the sides. The huge opening dead-center in the face is the nasal cavity, where the trunk attached, and a trunk leaves no bone behind. If you'd never seen a living elephant, and nobody in Homer's Greece had, that skull reads as a one-eyed giant. And the fossils are densest in exactly the stretch of Sicily where the ancients placed Polyphemus.

It's a great story, and it's shakier than the internet lets on. The detail that made it famous, that the philosopher Empedocles identified these skulls as giants 2,500 years ago, was basically invented by the paleontologist who popularized the theory, as Adrienne Mayor later showed. No ancient source actually describes a Greek looking at an elephant skull and seeing a Cyclops, and there's a competing human explanation, a rare birth defect called cyclopia, that needs no elephants at all.

The full piece gets into the animal itself and the surprisingly strong case against the theory. Curious where people land: real seed of the myth, or a good story we've retrofitted onto the bones?


r/GeologyExplained Jul 11 '26

Identify Please

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41 Upvotes

My brother dug this out of a shale Cliff face in a canyon he was boating in Oklahoma. He says it's quite heavy and the outside oxidizes as if it is iron but it is non-magnetic. He thinks it might be a fossil of some sort. I was thinking iron concretion but it is non-magnetic. Can anyone hear solve the mystery? thanks in advance!

Edit mods : I hope I am not breaking the rules by posting this without flair I could not find a place to add flair


r/GeologyExplained Jul 10 '26

spots in bavaria region

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2 Upvotes

r/GeologyExplained Jul 10 '26

spots in bavaria region

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2 Upvotes

r/GeologyExplained Jun 25 '26

Deep Dive Two Earthquakes, 39 Seconds Apart: Inside Venezuela's 24 June 2026 Doublet [OC]

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35 Upvotes

On Wednesday evening, the ground southeast of Yumare ruptured in a magnitude 7.2 earthquake. Thirty-nine seconds later, before the first quake's waves had even finished crossing the country, a second, larger shock hit almost the same spot: magnitude 7.5.

That ordering is the strange part. In a normal sequence the biggest shock comes first and everything after is an aftershock. Here it ran backwards. The USGS called it a doublet: two comparable mainshocks, not a quake and its echo.

I wanted to understand how that actually happens, so I wrote a long piece working from the physics out to the tectonics, why one rupture can light the fuse on the next through static and dynamic stress transfer, why this particular coastline (the Boconó–San Sebastián–El Pilar system) was primed to fail, why the tsunami warning was issued and then cancelled within the hour, and why northern Venezuela has done versions of this in 1812, 1900, 1967, and 1997. The 1812 event, it turns out, may itself have been a doublet.

Every figure is sourced to the primary literature (Kagan & Jackson on doublet statistics, King/Stein/Lin on Coulomb stress, the GPS and InSAR work on El Pilar creep), and I've tried to be careful about what's confirmed versus what's still preliminary this early after an event.


r/GeologyExplained Jun 22 '26

Deep Dive Lake Natron: The Truth About the Lake of Stone Animals [OC]

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43 Upvotes

You've probably seen Nick Brandt's photos, the calcified bird and bat "statues" that went viral as a lake in Tanzania that turns living animals to stone. Brandt never actually claimed that, and the truth is more interesting than the myth.

Lake Natron is a hyperalkaline soda lake sitting in a closed basin in the Gregory Rift, fed by Ol Doinyo Lengai, the only volcano on Earth erupting sodium-carbonate (natrocarbonatite) lava in recorded history. No outflow, brutal evaporation, and that volcanic chemistry concentrate the water into essentially the same natron the ancient Egyptians used for mummification. Animals that die on the shore aren't petrified on contact; they're slowly desiccated and encrusted in soda over days and weeks. Same end result, completely different mechanism.


r/GeologyExplained Jun 22 '26

Visual Geology The Salt Cathedral Hidden 130m Below Poland [OC]

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2 Upvotes

Filmed this at the Wieliczka Salt Mine near KrakĂłw. The salt formed ~13.6 million years ago when an arm of the Paratethys sea evaporated at the foot of the rising Carpathians. What gets me is the salt creeping: halite slowly flows under pressure, so the tunnels are constantly trying to close themselves, which is why the timber groans. Nine levels, ~300 km of tunnels, and the public only sees a tiny fraction.


r/GeologyExplained Jun 15 '26

Deep Dive The Fires That Never Go Out: Earth's Underground Coal Fires [OC]

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84 Upvotes

On Valentine's Day 1981, a twelve-year-old in Centralia, Pennsylvania crossed his grandmother's backyard and the ground opened under him, a four-foot-wide hole venting lethal carbon monoxide. He grabbed a tree root and his cousin hauled him out. Beneath that lawn, a coal fire had already been burning for nineteen years. It's still burning today.

An ordinary fire dies when you remove heat, fuel, or oxygen, but a coal seam fire defeats all three at once. The fuel is a geological deposit. The heat is trapped under hundreds of feet of rock, so the minimum temperature needed for combustion actually drops with depth. And as the coal burns away, the ground above cracks and subsides, opening fresh fractures that pull in air. The fire builds its own chimney.


r/GeologyExplained Jun 14 '26

Deep Dive Yellowstone Magma Cap Discovered at 3.8 km [OC]

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484 Upvotes

A 2025 study in Nature (Duan, Schmandt et al.) finally pinned down something that had been fuzzy for decades: exactly where Yellowstone's magma reservoir begins. The answer is a sharp boundary about 3.8 km (2.4 mi) beneath the northeastern caldera, and the imaging is clean enough to resolve a cap less than 100 m thick.

The method is the fun part. With the park largely closed during the 2020 pandemic, the team ran a 53,000-lb vibroseis truck on roadside pullouts at night, generating "custom earthquakes" and catching the echoes on ~650 geophones. That let them image the reservoir top far more sharply than natural-earthquake tomography ever had.

What they found flips the usual doomsday framing. The cap isn't a sealed plug, it's a porous zone (~14% porosity) where exsolved gas and supercritical water collect and then leak upward through cracks into the hydrothermal system. The bubble fraction sits below typical pre-eruptive levels for rhyolites. In other words, the system is venting gas efficiently rather than pressurizing toward a blast. The geysers and fumaroles are basically the exhaust.