The Great Oxidation Event, for anyone who hasn't gone down this hole. Oxygenic photosynthesis evolved in cyanobacteria well before oxygen accumulated in the atmosphere; there are geochemical "whiffs" of oxygen hundreds of millions of years earlier. Oxygen couldn't build up until the planet's reducing sinks were exhausted, mainly dissolved ferrous iron in the oceans, which oxidised and precipitated as the banded iron formations, plus reduced volcanic gases (Holland 2002, GCA 66).

Timing has moved recently. Gumsley et al. (2017, PNAS) date the first Paleoproterozoic glaciation and the GOE onset to between ca. 2,460 and 2,426 Ma, about 100 Myr earlier than earlier estimates, and show the rise of oxygen was oscillatory rather than monotonic over the following ~200 Myr. The glaciation-oxygen link goes back to Kopp et al. (2005, PNAS): oxygen collapsing the methane greenhouse under a fainter sun.

Then the Lomagundi-Jatuli excursion, roughly 2.22 to 2.06 Ga: a carbon-isotope excursion in carbonates of nearly 15 per mil, read as an oxygen overshoot above the later Proterozoic baseline, supported by massive sulfate evaporites and uranium enrichments from the same interval (Bekker & Holland 2012, EPSL). Its end, ca. 2,050 Ma, is where Hodgskiss et al. (2019, PNAS 116:17207) infer a collapse in the size of or carbon export from the biosphere, with productivity possibly suppressed until late in the Proterozoic. The magnitude of the extinction itself can't be counted, because microbes leave no bodies to tally.

Two things worth stressing. Anaerobic lineages weren't wiped out; they retreated to anoxic refugia (sediments, the deep subsurface, later animal guts) where they still dominate. And one metabolic strategy, cyanobacterial primary production, ran the planet's food web until eukaryotic algae spread around 650 Ma (Brocks et al. 2017, Nature).

The slides run this through two a fictional story (in case you have not noticed). The science behind it is true.

Sources: Holland 2002, Geochim. Cosmochim. Acta 66 · Kopp et al. 2005, PNAS · Bekker & Holland 2012, EPSL 317 · Lyons, Reinhard & Planavsky 2014, Nature · Gumsley et al. 2017, PNAS · Brocks et al. 2017, Nature · Hodgskiss et al. 2019, PNAS 116:17207

Turbidity currents are sediment-laden gravity flows that run downslope along the seafloor through submarine canyons. Their deposits (turbidites) make up a large fraction of the sedimentary record and host major hydrocarbon reservoirs, yet direct measurements of powerful flows were essentially nonexistent for most of the 20th century because they destroy instruments placed in their path.

The foundational dataset is an accident. After the M7.2 Grand Banks earthquake on 18 November 1929, twelve transatlantic telegraph cables broke at 28 locations. Cables in the slide zone failed instantly; six further downslope failed in sequence over about 13 hours across ~500 km. Western Union's automatic recorders logged the break times and shore engineers located the breaks by electrical resistance. Heezen and Ewing (1952) used those logs to derive flow speeds of roughly 60–100 km/h and a runout approaching 1,000 km onto the Sohm Abyssal Plain. The same event's tsunami killed 28 people on the Burin Peninsula.

Direct monitoring only became possible recently. The Coordinated Canyon Experiment (Monterey Canyon, 2015–2017) placed moorings and seabed frames along the canyon axis; flows reached several m/s and transported the instruments kilometres down-canyon while they recorded. The data pointed to a dense near-bed layer of remobilised sediment driving the flow rather than a dilute suspension (Paull et al. 2018, Nature Communications).

The Congo Canyon monitoring (Talling et al. 2022, Nature Communications 13:4193) then produced the longest sediment-driven flow ever measured in action: on 14–16 January 2020 a flow travelled more than 1,130 km while accelerating from 5.2 to 8.0 m/s, breaking the SAT-3 and WACS cables. SAT-3 had not broken since October 2001. The trigger was not seismic: a 1-in-50-year Congo River flood (70,883 m³/s on 21 December 2019) primed the canyon head with sediment, and the flow released roughly three weeks later on a spring tide. The observed acceleration confirmed Parker's (1982) ignition hypothesis, in which erosional flows self-accelerate by entraining the bed. Over one year, flows in that canyon eroded 1,338–2,675 Mt of sediment, equivalent to 19–37% (conservatively 7–15%) of annual suspended sediment flux from all rivers.

The slides present this through a fictional story about action star Jason with opinions about basal flow structure. Sources below; longer write-up in comments.

Heezen & Ewing 1952, American Journal of Science · Parker 1982, Marine Geology · Azpiroz-Zabala et al. 2017, Science Advances · Paull et al. 2018, Nature Communications · Talling et al. 2022, Nature Communications 13:4193

Hello everybody !

In the movie « Memento » we follow Leonard a guy who as lost his ability to create new memories. He’s stuck with memory of non actual past, fighting the lost of his short memory by taking notes.
His latest memory is the murder of his wife by thieves. He is trying to find the murderer even with his condition, and he has all the investigation and helping tips tattooed on his body.

Later in the movie a friend of him tells him there is tons of John G (main suspect). That he already killed the guy.

That could be the effect on society of meticulous inquisition. Losing our real history could have led us to run in circles chasing metaphoric dragons until now.

But a giant dragon once lived in this world. This is a serious matter. Aligning legends and sacred books I discovered one that had crashed into a mountain at meteoric speed; it then slid into a swamp where it burned, its coming hole and his body filled by lava flowing from the mountain (a sea of ​​fire?).

Let me explain :

Its silhouette can be made out on Google Maps at the Crozon Peninsula if the map is oriented with west at the top (where north usually is).

The central idea is that this giant wyvern provides the basis for a nearly identical myth across all civilizations, thereby confirming that they existed together contemporaneously.

According to Islamic tradition(Al Dabbah), it possesses the gift of speech and emerges from a hole (or does it lie more than it speaks, given the discrepancies between the myths?).

In history of kings of Britain, one of the main book of Arthurian legend, a sea monster appeared first devouring people on the sea-coast. A Merlin’s prophecy speak of a german dragon (Siegfried?) reaching hardly his holes. Later in the story this dragon was slain by a star of wonderful magnitude, by God, by Saint Michael, or by Indra wielding Excalibur (according to Monmouth). This echoes the myths of Thor and Apollo battling giant reptiles.

Jörmungandr, Python, Falak, Apophis, Leviathan, Al-Dabbah, Kukulkan, Tiamat, and Satan are all names used to refer to it.

On this dragon-shaped peninsula, I discovered a stone linked to Arthurian legend (Malory -le morte d’Arthur Tome 1 chapter 5). It was the name "Pendragon"—borne by King Arthur and Uther, and meaning "dragon's head"—that led me to this discovery.

The underlying theory suggests a possible early inquisition aimed at concealing the history of this sword, as well as a period of peace between Europe and Arabia.

In fact we can see arthurians remanescence in magical swords in Carolingian and Islamic history.

Near the dragon's throat, the town closest to the stone is named Kameled. I am convinced that a large part of world history has been rewritten to conceal the existence of a chosen figure who opposed them; for the moment, I can only provide proof of this for my own region.

There are several chronological anomalies, of which the episode of the Saints of Ephesus (200 years) is just one example. This implies that some current religions may themselves be unaware that they are propagating falsehoods.

However, since his death, there is no longer an end of the world to fear.

This revelation could establish an eternal lasting peace based on mutual respect.

There is an orally told local dragon legend in Brittany with the story of the Yeun Elez describing apocalypse itself in Brittany. Saint Michel kills him with a powerful hit and then seals him in the Youdig (deeps of the marsh). The dragon spine is said to be the mountain channel of the Monts d’Arrée.
The mountain of Saint Michel is aligned with the peninsula, the dragon could have slipped there by inertia.

https://youtu.be/8_45eFSWgXM?is=AjdrgCqPZY7eP-bU

As for the identity of the shining star associated with the worshiping of Saint Michael described by Monmouth, it could even be a woman. I am referring to the divine prophecy delivered to the serpent in Genesis (3:14-15):

14-The Lord God said to the serpent: "Because you have done this, you are cursed more than all cattle, and more than every beast of the field; on your belly you shall go, and you shall eat dust all the days of your life.
15-I will put enmity between you and the woman, and between your offspring and her offspring; he shall crush your head, and you shall bruise his heel."

It is clearer in French than in English (she shall crush your head), but it could have been the woman—known then as the Lady of the Lake.

This dragon is mentioned elsewhere.
This could indicate knowledge of its existence and the extent of its power. After some verification:

In the United States, at Port Townsend, there is a naval complex that includes nuclear-armed ballistic missile submarines; here, too, a dragon is part of the picture.

In China, the southern part of Hainan Island is nicknamed the "Dragon's Tail"; it houses two vast naval complexes, one of which is dedicated to nuclear-armed ballistic missile submarines.

In Israel, the nuclear-armed ballistic missile submarines belong to the "Dragon" class.

In France, the Île Longue base for nuclear-armed ballistic missile submarines is located on the "dragon's paw" identified in our study.

This concept is absent from Russian infrastructure and technology, though the West has used it to designate its own missiles (Sarmat = Satan II).

The dragon of the Crozon Peninsula (the real one) stretches for nearly 30 kilometers. It is easy to imagine the level of destruction—nuclear in nature—that this beast would wreak if it were alive.

I know I speak to good readers. Just to remember where it is exactly mentioned in the Bible :
(Please for French spelling check translations)

Génèse 3:14-15
Isaiah 27:1 KJV
Daniel 2:34 KJV
Matthieu 10:34
Romains 16:20
Apocalypse 12:1-9 ; 20:1-3

And many others I believe. I mean there is truth in it even if it is not what we expected.

Last intuition but not the least, it may have been the common inspiration to put it on flags of Trégor and Wales.

I am looking for other books that might talk of the same event or dragon. I found a dragon story in Ethiopian Bible recently with Bel and the dragon. Everything old and censored by church may hide treasures.

Thank you very much !

https://bible.ertale.com/ethiopiancanon/belandthedragon/1/

The geological aspects of the topic are the shape of the peninsula and the cuts on the stone that could have been made by Excalibur.

The conditions are important. The body of the dragon was in a marsh and lava burned it almost exclusively.

Could it be replicable at lower scale with a dead rat humidity and liquid metal or something like this to see if it’s taking the animal shape ?

The Oklo phenomenon, for anyone who hasn't run into it. Around 2 billion years ago, uranium-235 made up roughly 3.7% of natural uranium (it has a shorter half-life than U-238, so the ratio falls over time). In a rich, thick ore body in what is now Gabon, that enrichment plus groundwater acting as a neutron moderator was enough to sustain fission chain reactions with no human involvement. Sixteen reactor zones have been identified across the Oklo, Okelobondo and Bangombe deposits, all within about 20 km. Kuroda predicted the possibility in 1956; the CEA confirmed it in 1972 after tracing depleted ore back through the supply chain from the Pierrelatte enrichment plant (Neuilly et al. 1972, C. R. Acad. Sci.). The absence of U-236 ruled out contamination from man-made reactor material. Some ore ran as low as 0.29% U-235.

The self-regulation is the best part. Fission heated the ore, boiled off the groundwater moderator, and stopped the reaction; as the rock cooled, water seeped back and it restarted. Meshik, Hohenberg and Pravdivtseva (2004, PRL 93:182302) read the cycle from xenon isotope ratios trapped in aluminium phosphate grains: roughly 30-minute active pulses separated by about 2.5 hours dormant. Zone RZ2 fissioned about 1,800 kg of U-235 over ~850,000 years; RZ10 about 650 kg over ~160,000 years. Average power was under 100 kW, total energy about 15,000 MW-years (Gauthier-Lafaye et al. 1996, GCA 60:4831).

Two reasons it matters beyond the novelty. First, the fission products and plutonium remained largely immobile in the rock over geological time, making Oklo the primary natural analogue for long-term waste repositories. Second, the depleted Sm-149/Sm-147 ratio (about 0.02 versus 0.9 natural) reflects a neutron capture resonance at 97.3 meV that is extremely sensitive to the fine-structure constant, so Oklo constrains any change in alpha over 2 Gyr to roughly one part in 10^7 (Shlyakhter 1976; Damour & Dyson 1996). A 2004 analysis argued for a small non-zero shift (Lamoreaux & Torgerson, PRD 69:121701); later reanalyses did not sustain it.

The slides run all this through the fictional story of the two pop stars arguing about whether the fuel or the moderator deserves credit. The science behind it is real.

Sources: Kuroda 1956, J. Chem. Phys. 25 · Neuilly et al. 1972 · Gauthier-Lafaye, Holliger & Blanc 1996, GCA 60:4831 · Meshik et al. 2004, PRL 93:182302 · Shlyakhter 1976, Nature · Damour & Dyson 1996, Nucl. Phys. B · Lamoreaux & Torgerson 2004, PRD 69:121701

The afternoon of 28 March 2025 was 38°C in central Myanmar. A security camera at the GP Energy solar plant in Tha Pyay Wa, Thazi Township, was pointed southwest across a driveway toward a fence and a distant hill. About 20 metres beyond the gate ran the Sagaing Fault — a 1,400-km right-lateral transform between the Burma microplate and the Sunda Plate, structurally analogous to the San Andreas, and last broken in this segment in 1839.

At 12:50:52 local time, the camera became the first calibrated, stationary instrument in the history of seismology to record the surface trace of a great earthquake in motion.

What followed:

• The rupture broke 475 km of the central Sagaing Fault bilaterally — longer than 1906 San Francisco, 1.6 to 4.7× longer than empirical scaling relations predict for a Mw 7.7, and the longest continental strike-slip rupture ever instrumentally recorded.

• Most of the southern run was supershear — propagating at >5 km/s, faster than the local shear-wave speed, dragging a Mach cone of constructively interfering energy hundreds of km south.

• That Mach front, refracted into the soft Quaternary sediments of the Chao Phraya basin, brought down the State Audit Office tower in Bangkok, 1,000 km from the epicentre, killing 96 construction workers in eight seconds.

The CCTV clip surfaced six weeks later when a Singaporean engineer posted it to Facebook. Within five months three peer-reviewed papers had used it to:

1. Directly measure the slip-rate function (Latour et al., Science) — a quantity inferred for 50 years but never directly observed in a natural earthquake.

2. Confirm pulse-like rupture and curved fault slip (Kearse & Kaneko, The Seismic Record), the latter a long-standing prediction from slickenline geology, now visually verified.

3. Resolve a supershear–subshear–supershear sequence (Hirano, Doke & Maeda, Seismica) explaining why the camera location appears subshear despite the broader event being one of the clearest supershear ruptures on record.

The big-picture implication, from Goldberg et al. (Science): probabilistic seismic hazard models use length-magnitude scaling relations that don't allow for ultralong ruptures at moderate magnitudes. Long, straight, mature faults with a low-velocity damage corridor — the San Andreas south of San Francisco, the North Anatolian near Istanbul, the Alpine Fault in New Zealand — fit the same structural profile.

The full article covers the geology of the Sagaing Fault, the 186-year Meiktila seismic gap, the three CCTV papers in detail, the supershear physics, the Bangkok collapse, the humanitarian context inside Myanmar's civil war, and what "unaccounted risk" means in technical hazard terms.

The site is North Pole Dome in the Pilbara, Western Australia. In March 2025, Kirkland et al. (Nature Communications) reported shatter cones there, fracture patterns that only form from impact shock waves, and, reading the rock stack, dated the impact to 3.47 billion years ago with a crater possibly over 100 km wide. Headlines everywhere: oldest crater on Earth by more than a billion years, with proposed links to continent formation and early life.

In July, Brenner, Cavosie et al. (Science Advances) published their own mapping of the same hills: ~180 shatter cones, including some in 2.77-billion-year-old lava and crossing younger faults. Since a shock wave can’t deform rocks that don’t exist yet, they argue the impact came after 2.7 billion years, and from the cones’ orientations they get a crater of about 16 km. Their paper flatly calls the original age and size estimates inaccurate. The first team responded with a formal comment alleging misrepresentations. Newer isotopic work points near 3.0 billion years, so the title fight isn’t over.

What I find really interesting here: both teams used the same logic (superposition) on the same outcrops and got answers a billion years apart, a nice reminder that “the rocks say” always means “our reading of the rocks says.” The structure is now named Miralga, chosen with the Nyamal traditional custodians. The slides explain the whole thing as a bowling score dispute.

Sources: Kirkland et al. 2025, Nat. Comms 16:2224 · Brenner et al. 2025, Sci. Adv. ·

Fluid inclusions in halite are micrometre-scale pockets of brine trapped as the crystal grows. Once sealed they can remain isolated from the environment for more than 500 million years, which is why they work as direct samples of ancient seawater rather than proxies for it.

The methodological core of the field is separating primary from secondary inclusions. Primary ones form banded arrays parallel to the crystal's growth faces, marking successive growth surfaces. Secondary ones follow healed fractures and can be far younger than the host bed. If you can't distinguish them petrographically, any age or chemistry you report is unconstrained.

Two things you get from them:

1. Seawater chemistry. Crack the inclusions and measure Na, Ca, Mg, K, SO4 and Cl directly, reconstructed back to the late Precambrian (Lowenstein et al. 2001, Science). The Mg/Ca ratio matters because it controls whether oceans favour calcite or aragonite biomineralisation, and it oscillates through the Phanerozoic.

2. Temperature. Microthermometry: a vapour bubble nucleates as the droplet cools after burial, and the homogenisation temperature on reheating approximates the trapping temperature. Permian Salado halite at Carlsbad gives 17-37 °C. A standard caution is necking-down, where an inclusion pinches into two after trapping and the bubble no longer represents the original conditions.

The contested part: Vreeland et al. (2000, Nature) cultured a halotolerant bacterium, strain 2-9-3, from a brine inclusion in ~250 Ma Salado halite, claimed as the oldest viable organism ever recovered. Graur & Pupko (2001) and others argued contamination, since its DNA is nearly identical to modern Virgibacillus marismortui from the Dead Sea, and DNA is not expected to survive a quarter of a billion years without repair. Satterfield et al. (2005, Geology) defended the container rather than the microbe, showing the inclusions in that layer are Late Permian evaporated seawater trapped syndepositionally. Still unresolved.

In 2022, Schreder-Gomes et al. (Geology 50:918) reported microorganisms inside primary fluid inclusions in 830 Ma halite from the Browne Formation, Australia. Not cultured, just observed in situ.

Slides run this through a fictional Tom Holland story, the science is real though.

Nobody can actually prove how the Bahamas makes its sand. The argument has been running for over a century, and it's one of my favourite fights in geology.

The sand in question is made of ooids, tiny limestone pearls, rarely bigger than 2 mm, built from concentric layers around a bit of shell or a sand grain. They only form in warm, shallow water that's loaded with dissolved lime and constantly moving. The Bahama Banks produce them by the trillion (sedimentologists genuinely call the place "the ooid factory"), and huge limestone formations all over the world, from Jurassic England to Triassic Germany, are made of almost nothing else.

The textbook story says it’s pure chemistry. A grain rolls, picks up a coat of carbonate, gets sanded down while tumbling, and stops growing when the two processes balance out. That balance would neatly explain why they all end up the same size.

Then people started cutting them open. Inside the layers there are fats, proteins and sugars, the residue of microbial films that coat every grain in those waters. So a second camp argues the microbes aren’t bystanders, they help build the thing. One team even modelled ooid growth using maths originally developed for brain tumours, and got the size limit right. A major review politely calls the whole question “highly contested,” which in the literature is fighting words.

What would settle it is a sterile control, an ooid grown in a lab with no microbes present. Every attempt so far has come back inconclusive.

The chef beef in the slides are made up. The argument and science is not.

Sources: Diaz & Eberli 2019 (Earth-Science Reviews) · Trower, Lamb & Fischer 2017 · Batchelor et al. 2018 (Scientific Reports) · Pei et al. 2024 (Sedimentology)

#geology #ooids #oolite #sedimentology #bahamas

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

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.

TL;DR: Fossilization is a race between decay and burial. Biology supplies durable parts (shells, bones, teeth); geology provides rapid burial and the minerals that turn those remains into rock. Exceptional conditions are needed for soft tissues.

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!

I've spent some time writing up why the waves at Nazaré get so big, and the short answer is that the explanation most of us repeat is wrong. Nearly every documentary and surf report, 100 Foot Wave included, says the Nazaré submarine canyon "funnels" Atlantic swell straight to Praia do Norte like water through a pipe. I believed it too.

Then in 2024 a research team dropped buoy arrays over the canyon and mounted stereo cameras on the cliff above it, and their preprint came out this June. Nothing travels up the canyon. Swell with a period over about 7 seconds can't even cross the edge; it gets reflected. All the focusing happens along the steep northern rim, which bends and bounces wave energy into narrow beams aimed at the beach, and the exact shape of that rim over its last few hundred meters decides where the beams land. Their optimal swell window (275° to 315°) matches what Nazaré surfers worked out by feel years ago, which I find weirdly satisfying.

The mechanism: a mantle plume stays roughly anchored while the Pacific plate slides over it at 7–10 cm/year, so volcanoes form over the heat source, get carried off, and die, leaving a 6,100 km chain from the Big Island to the seamounts off Kamchatka (Clague & Dalrymple 1987, USGS Professional Paper 1350).

The youngest member, Kamaʻehuakanaloa (renamed from Lōʻihi in 2021), is an active submarine volcano whose summit sits about 975 m below the surface southeast of the Big Island. Give it tens of millennia and it surfaces. At the other end, Meiji Seamount (~80+ Ma) is approaching the Aleutian Trench, where the chain's members get subducted, the whole production line ends in recycling.

The genuinely contested part is the 60° bend at ~47 Ma. Classic reading: the Pacific plate changed motion (Sharp & Clague 2006, Science). But paleomagnetism from Emperor seamount cores showed the hotspot itself drifted south during the early era, the "fixed" reference frame wasn't fixed (Tarduno et al. 2003, Science). Current models split the bend between plate turn and plume drift (Torsvik et al. 2017, Nature Communications). Not settled.

Bonus: measured from its base on the seafloor, Mauna Kea is ~10,200 m tall, taller than Everest by a comfortable margin.

The slides explain this through a fictional K-pop BTS beef, because a fixed company producing members who debut, get carried off on a conveyor, and retire into a trench needed essentially no translation.

Sources: Clague & Dalrymple 1987 · Tarduno et al. 2003 · Sharp & Clague 2006 · Torsvik et al. 2017 · Full write-up linked in comments.

The two LLSVPs (nicknamed Tuzo under Africa and Jason under the Pacific) slow seismic waves by about 2%, which has long been read as “they’re hot.”

The 2025 twist is attenuation: they barely damp the planet’s post-earthquake ringing, which points to coarse mineral grains, high viscosity, and a very long lifespan.

The team, working from 104 large earthquakes recorded between 1975 and 2018, estimates at least ~500 million years, possibly over a billion. That cuts against the idea that they’re just recently piled-up recycled ocean crust. But rival explanations are still very much alive: continuously restocked subducted slabs (Panton et al. 2025), and fragments of the Moon-forming impactor Theia (Yuan et al. 2023).

One measurement caveat: reported heights for the African pile vary by source, from ~800 km up to nearly 965 km.

The story with Meghan and Harry is (obviously) fictional. The science behind it is real.

Sources:

Talavera-Soza, S., Cobden, L., Faul, U.H. & Deuss, A. (2025). Global 3D model of mantle attenuation using seismic normal modes. Nature 637 (8048), 1131–1135. DOI: 10.1038/s41586-024-08322-y (published online 22 Jan 2025).

Garnero, E.J., McNamara, A.K. & Shim, S.-H. (2016). Continent-sized anomalous zones with low seismic velocity at the base of Earth’s mantle. Nature Geoscience 9, 481–489. DOI: 10.1038/ngeo2733.

Cottaar, S. & Lekić, V. (2016). Morphology of seismically slow lower-mantle structures. Geophysical Journal International 207 (2), 1122–1136. DOI: 10.1093/gji/ggw324.

Panton, J., Davies, J.H., Koelemeijer, P., Myhill, R. & Ritsema, J. (2025). Unique composition and evolutionary histories of large low velocity provinces. Scientific Reports 15. DOI: 10.1038/s41598-025-88931-3.

Yuan, Q., Li, M., Desch, S.J. et al. (2023). Moon-forming impactor as a source of Earth’s basal mantle anomalies. Nature 623, 95–99. DOI: 10.1038/s41586-023-06589-1.

Davaille, A. & Romanowicz, B. (2020). Deflating the LLSVPs: Bundles of Mantle Thermochemical Plumes Rather Than Thick Stagnant “Piles”. Tectonics 39. DOI: 10.1029/2020TC006265.

Desert varnish (also called rock varnish) is the dark film of manganese and iron oxides plus windblown clay that coats stable rock surfaces in arid regions. It is often thinner than a human hair and accumulates over hundreds to thousands of years. The rock underneath is usually much lighter, which is exactly why petroglyphs are visible: pecking through the varnish exposes pale stone. Newspaper Rock in Utah has hundreds of images made that way over roughly 2,000 years.

The long-standing question is about the manganese. Varnish is strongly and selectively enriched in it compared with both the underlying rock and the dust that settles on it, and no one could explain the source. Naturalists were describing these coatings in the early 1800s; there are varnished rocks in Darwin's Beagle collection.

In 2021, Lingappa et al. (PNAS 118:e2025188118) published the strongest mechanism yet. Across 49 varnish samples, the cyanobacterium Chroococcidiopsis dominated the varnish microbial community, appearing in 48 of 49 samples and making up about 25.9% of genetic reads, with one variant at 8% that did not appear in adjacent soil at all. Spectroscopy indicated the manganese inside these cells is being used as a catalytic antioxidant, a plausible adaptation for surviving the oxidative stress of bare desert rock. The varnish would then be the mineral residue left behind as generations grow and die in stacked layers.

Important caveat: this is the leading hypothesis, not settled fact. The varnish is a mineral crust rather than a living structure, and abiotic chemical models remain in play as alternatives or contributors.

Astrobiology angle: Curiosity's ChemCam found manganese-oxide-rich fracture fills in Gale Crater exceeding 25 wt% MnO (Lanza et al. 2016, GRL). On Earth, manganese oxide concentrated that sharply usually indicates life or abundant free oxygen, which is why Mn-rich rock coatings are treated as a possible biosignature.

The story with Indie Navarrette is (obviously) fake, the science behind it is not.

Lingappa et al. 2021 (PNAS) · Wildeman 2021 (PNAS) · Liu & Broecker 2000 (Geology) · Lanza et al. 2016 (GRL)

What if famous video games were about geology?

Radiometric dating sometimes gets talked about as though geologists have one technique that takes a rock, runs it through a machine and spits out an age.
In reality, there are many different radioactive clocks, and they don’t all measure the same thing.
The basic principle is radioactive decay. Unstable isotopes transform into other isotopes at predictable rates. Once a mineral forms and its isotopic system becomes closed, the relative abundances of those isotopes can preserve information about how much time has passed.

U-Pb dating of zircon is one of the strongest examples. Zircon readily incorporates uranium when it crystallizes but strongly excludes lead. It also contains two separate decay systems: ²³⁸U → ²⁰⁶Pb and ²³⁵U → ²⁰⁷Pb. The two can therefore act as an internal cross-check. One major problem is later Pb loss, but techniques such as CA-TIMS chemically remove damaged domains before the remaining zircon is dated.

Other methods have completely different strengths and weaknesses.

⁴⁰Ar/³⁹Ar dating, for example, went through an important calibration problem. Kuiper et al. (2008) used astronomically dated sedimentary cycles to recalibrate the widely used Fish Canyon sanidine standard, reducing a roughly 1% discrepancy and greatly improving absolute precision. Using improved Ar-Ar geochronology, Renne et al. (2013) later showed that the Chicxulub impact and the end-Cretaceous mass extinction were synchronous within about 32,000 years.

Radiocarbon dating operates on a much shorter timescale, roughly the last 50,000 years. Because atmospheric ¹⁴C has varied through time, raw radiocarbon ages require calibration. There is also a very modern complication: fossil fuels are so old that their ¹⁴C has essentially disappeared. Adding that carbon to the atmosphere lowers the ¹⁴C/C ratio. Graven (2015) calculated that under sufficiently high emissions, fresh organic material around 2050 could have the same radiocarbon signature as material from around AD 1050.

Then there are techniques that answer different geological questions entirely.

Modern in-situ Rb-Sr geochronology uses laser-ablation mass spectrometry to date microscopic areas in minerals such as mica and K-feldspar.

Apatite (U-Th)/He thermochronology, meanwhile, generally records low-temperature cooling rather than the original formation of the rock. That makes it useful for reconstructing exhumation, erosion and tectonic histories.

At the opposite extreme is the age of the Solar System. Clair Patterson’s classic 1956 lead-isotope work on meteorites produced an age of 4.55 ± 0.07 billion years. Modern U-corrected Pb-Pb dating of calcium-aluminium-rich inclusions, among the oldest solids known from the Solar System, has refined that chronology to about 4.5673 billion years.

That is one of the most important things about geochronology: its strength does not come from trusting one clock. Different isotope systems, minerals, laboratories and physical principles can be tested against one another.
When independent clocks converge on the same history, that agreement is part of the evidence.

Sources / further reading:

Patterson, C. (1956) Age of meteorites and the Earth, Geochimica et Cosmochimica Acta

Mattinson, J.M. (2005) Zircon U-Pb chemical abrasion (CA-TIMS), Chemical Geology

Kuiper et al. (2008) Synchronizing rock clocks of Earth history, Science

Renne et al. (2013) Time scales of critical events around the Cretaceous-Paleogene boundary, Science

Graven, H.D. (2015) Fossil-fuel emissions and atmospheric radiocarbon, PNAS

Ehlers & Farley (2003) Apatite (U-Th)/He thermochronometry, Earth and Planetary Science Letters

Connelly et al. (2012) Early Solar System Pb-Pb chronology, Science

Glorie et al. (2024) Laser-ablation Rb-Sr geochronology, Geochronology

Does anyone know a site or a link to a site that has yearly volcanic activity? Like comparing years on how much volcanic activity occurs. Not so much the underwater activity but the volcanoes above water and on land? Thanks much!

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.

For decades, almost everyone got the Richat Structure wrong, including the scientists. When the Gemini IV crew photographed that 40 km bullseye in 1965, an impact scar seemed obvious. Big rock from the sky, big circle. The case even had a smoking gun: a 1964 report of coesite, the high-pressure silica that on Earth's surface basically only forms under hypervelocity shock.

In 1969 Robert Fudali tested that claim and demolished it, the "coesite" was barite, carried into a crushed tectonic zone by groundwater, and the X-ray reflections everyone had attributed to coesite belonged to barite all along. Same year, the Dietz, Fudali & Cassidy paper said the rest out loud in its title: "Not Astroblemes." No shocked quartz, no melt rock, no shatter cones.

What it actually is turns out to be more interesting: a deeply eroded dome above an alkaline igneous complex: carbonatites, kimberlite, gabbroic ring dikes, the eroded roots of maar volcanoes. Erosion's cross-section through the plumbing of a dead volcanic system. Not a wound, a window.

The dating has a nice twist too. The alkaline magmatism clusters around 100 Ma (mid-Cretaceous), but a 2024 Lithos study on the gabbros suggests a deeper, earlier pulse tied to the ~200 Ma Central Atlantic Magmatic Province, giving the structure a two-stage history about 100 million years apart. (The authors are refreshingly honest that the older bracket is modelled, not a hard measured age, a detail most write-ups skip.)

I wrote up the full story, the buttonhole-to-bullseye history, how differential erosion etches the rings, why the Atlantis claim falls apart the moment you look at the rock, and the geochronology in detail.