A Geologic Mystery in Madagascar; Solved at Last?

In Madagascar is a strange massive natural ring in the ground which measures nearly 10 miles or 16 kilometers across. This geologic oddity is not an impact crater or a caldera, but instead something completely different. This is the story of this still unnamed feature which formed due to its association with an ancient massive outpouring of lava known as a flood basalt.
Thumbnail Photo Credit: Google Earth, Image © 2024 Airbus. This image was overlaid with text and then overlaid with GeologyHub made graphics (the image border, the orange dashed line to indicate the feature's rim, & the GeologyHub logo).
NOTE: Collecting is NOT allowed, and neither is trespassing at Buell Park (in Arizona) which is ALL private property! Please do not trespass onto the kimberlite pipe in Arizona (which contains no diamonds) referenced in this video.
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Google Earth imagery used in this video: ©Google & Data Providers
This video is protected under "fair use". If you see an image and/or video which is your own in this video, and/or think my discussion of a scientific paper (and/or discussion/mentioning of the data/information within a scientific paper) does not fall under the fair use doctrine, and wish for it to be censored or removed, contact me by email at [e-mail] and I will make the necessary changes.
Sources/Citations:
[1] MELLUSO, LEONE & Morra, Vincenzo & BROTZU, PIETRO & Tommasini, Simone & Renna, Maria & DUNCAN, ROBERT & Franciosi, L. & D'AMELIO, FOSCO. (2005). Geochronology and Petrogenesis of the Cretaceous Antampombato-Ambatovy Complex and Associated Dyke Swarm, Madagascar. Journal of Petrology. 46. 10.1093/petrology/egi044.
[2] White, S. M., J. A. Crisp, and F. J. Spera (2006), Long-term volumetric eruption rates and magma budgets, Geochem. Geophys. Geosyst., 7, Q03010, doi:10.1029/2005GC001002.
0:00 A Geologic Mystery
1:01 Ruling out Candidates
2:28 150 Million Years Ago
2:56 Flood Basalt
3:46 Doming

[@scillyautomatic]

You are one steely eyed geology-man for figuring this one out!

[@genericalfishtycoon3853]

Hard to find any bright side to what's going on in Madagascar, but once the islanders finish completely deforesting the entire island here this year, and everything erodes away, it will probably be very interesting to study geologically. (You know, cuz it will be nothing but barren rock) 😢 RIP rainforest.

[@zigzigler5111]

It will grow back. Not in our lifetime but sometime in the distant future it will be green again

[@genericalfishtycoon3853]

@@zigzigler5111 I hope so bud, I really do.

[@alanbiancardi2531]

It happens. I will not lose any sleep over it

[@genericalfishtycoon3853]

@@alanbiancardi2531 🙄 "I'm so apathetic that I really care that you know it." Lol Ok bud but be careful with that edge alright?

[@TaLeng2023]

Happens in many places. They'll reforest when they're forced to.

[@notmuch8078]

Large igneous provinces are one of my favourite things to learn about, I enjoys watching your volcano vids because I learn about volcanos and features I'd never heard of, keep it up ☺️

[@ZebaKnight]

Very cool! I love your clear explanations and graphics. Both are especially helpful for complex situations like this one.

[@davidsavage6227]

Could you do a video on Bermuda? I’ve read that the island is not sinking and may even be rising because of some kind of non-volcanic reason. Also, could you explain how Stone Mountain is growing? I always enjoy your videos and look forward to the next ones.

[@TimNevins]

Good stuff, as usual! I enjoy the content, production, and presentation. The thing that blew my mind was that there are usually 40-something active volcanos going off.

[@michaelnettles-kf2bl]

As always, I learned something. Thank you.

[@thomasgoodwin2648]

Class is always in session. And so much easier with a classy teacher😉

[@paulw3182]

Great Video

[@xwiick]

Thanks for all of your hard work man!

[@Astrofrank]

Quality content, as expected. ❤

[@trishkillian2459]

Thank you for the clear and understandable report.

[@suzettebavier4412]

Thanks a whole bunch, Timothy

[@user-pi4wj7bm4z]

An interesting article. Greg

[@chasemclain6235]

Love these kinds of videos 🤗

[@panasclepias2937]

While we're taking requests, anyway we can get a video on the geology of Connecticut? I grew up there, and culturally it's a thoroughly boring place. But it's only in the last ten years that I've come to realize just how crazy the geology is there.

[@firestorm7919]

This video re-ignited my curiosity about that strange, massive almost perfectly circular formation northeast of Crater Lake in Oregon. I’d love for you to make a video explaining how that giant circle formed because it doesn’t look like it could be a caldera or impact crater.

[@sgtbilkothe3rd]

There are already several web pages explaining this feature.

[@willtricks9432]

Great summary, Thank you.

[@AuthenticDarren]

Wowzers! That sounds pretty rare!

[@GingerMafia48]

this reminds me of the Vox video about a mysterious village that just popped up in the middle of a similar (if not the same?) formation on Madagascar they went to the island after talking with a PhD student who had studied the formation and gone there for field work years previously, and made contact with the village. overall, a pretty cool video about a pop up village in the middle of a geologic wonder which was discovered entirely through google maps!

[@barbasmas]

Hehe, so fun to see this. I think ive seen one other video on this on youtube somewhere. I myself found these on google maps in 2018, and later in 2019 wrote an essay on them for a small course on volcanism in Stockholm University. Now i work with something completely different, but it was so fun to explore. I theorised they would either be calderas or circular ring intrusions. I had been in touch with the geological society of madagascar to ask about them, and they happily provided with scientific reports about the general area. There are probably more of these geological formations further northeast, some bigger even, but less obvious. I think at least 4. Would love to see a part 2 of this video for the rest. Or the Androy complex/caldera to the south, if you havent already done it

[@howieb3344]

Very interesting. Thank you and have a great day.

[@azopalinc]

Madagascar is so rich in gemstones!

[@BellaBarossa]

I noticed several years ago that Madagascar has a lot of circular features that are not volcanoes nor impact structures, or are not formally identified as either. These are especially noticeable on Google Maps when the terrain layer is on. I wrote to several geologists about these, but none of those who responded could offer much insight, except to say that there was a scarcity of data on many geological landforms on that island.

[@simix6915]

Speaking of this wonderful island, you should cover the mysterious maars and cinder cones on the northern part

[@TheSpaceEnthusiast-vl6wx]

Thanks as always! It is always good to discuss these kinds of features, especially this unusual formation. I wonder if it has a name yet.

[@frankforce9241]

Thank you very much! I feel enlightened! Take care Frank

[@Mastercrack_GS]

How wonderful the laccoliths are, but the bad thing is that mining companies may come to want to exploit some of the precise minerals there are.

[@baneverything5580]

Diamonds were found in Louisiana....and it quickly went hush-hush. To the east of where they were found I learned there is a buried volcano in Jackson, Mississippi.

[@cacogenicist]

Diamonds in Louisiana could have bumped down the Mississippi, having eroded out of moraines left from the last glacial advance -- with the diamonds originally having been transported southward by glaciers that had advanced over kimberlites in Canada. Diamonds are occasionally found in moraines and creeks in the Midwest (along with a little fine gold, also from Canada for the most part).

[@interstellarsurfer]

​​@@cacogenicistNo, there is no need for Canadian diamonds to explain anything. There are extinct, dormant, and volcanoes across the American south - Arkansas, Missisippi, Georgia, both Carolinas, and Florida. There is even a 'secret' exposed kimberlite pipe in a national park in Tennessee.

[@genericalfishtycoon3853]

They found the largest lithium deposit on the planet right out behind my house here in Oxford county Maine. Thankfully it hasn't turned this beautiful area into a giant pit mine... Yet.

[@interstellarsurfer]

​@@cacogenicistThere are extinct, dormant, and active volcanos all across the American south. Tennessee doesn't have any documented volcanos - but it does have 'secret' exposed kimberlite pipes in a national park. Diamonds are everywhere.

[@goldenhate6649]

From what I can tell, they would have to make one hell of an offer to get access to that property. The owners likely have mineral rights.

[@susiesue3141]

Thanks for sharing! Very interesting. 😊

[@bavondale]

very cool explanation

[@ozzymandius666]

Fascinating.

[@EraX52]

Great video. I remember you had a video before of the Ilopango volcano in El Salvador, which was one of my favorite videos. Can you please bring the video back.

[@xwiick]

The video was taken down due to license issues with photos/video's used along with many more video's so they all have to be remade sadly, He has remade several. I agree Ilopango should be a priority such fascinating system tho probably not as eye catching as Crater lake and other American Volcano's to the "normies"

[@geradkavanagh8240]

I've only waited about 3 years for you to get back to this anomaly.

[@RiddleBoxBree]

Any chance of doing a video on how fossils are formed? Its the most asked question i always get as a paleontologist!

[@genuinetuffguy1854]

You are like the Surerock…I mean…Sherlock Holmes of Geology.

[@lukedawg2787]

Although slightly different but similar in how they were formed. You should look up Beacon Rock in Washington state. It is the massive core of an extinct volcano that was exposed during the massive floods of the Columbia River. So cool to visit knowing that you a climbing up the heart of a volcano that at some point looked like Mt Saint Helens or Mt. Rainier.

[@abigalanderson7494]

Very cool I will have to check it out

[@abigalanderson7494]

Mount stuart is from mexico

[@jimmcintosh9045]

Looks a bit like the Ardnamurchan Peninsula caldera in West Scotland.

[@Nightscape_]

If this is true, feels like you should win a ticket for two to Madagascar.

[@genericalfishtycoon3853]

Not going to be much left to visit at the rate they're deforesting the island. Check out satellite time lapses of the last decade. It's mind boggling.

[@seanc6128]

Hey Mr. GeologyHub could you share some insight about what this large circular feature in Oregon is? 43°13'44.4"N 121°30'41.9"W

[@matusknives]

Since you mentioned it - I would love if you would make a little more detailed video on Kymberlite pipes. The concept still sounds like science fiction to me because of my lack of knowledge on the topic.

[@sabunkompas]

I think you can cover Indonesia's Eye of Borneo in South Kalimantan.

[@chimknee]

Thanks.

[@ModernProspector]

Kimberlite pipes are often found along the margins of collapsed calderas. Check out the Virginia Dale Ring Dike on the Colorado Wyoming border. Most of the diamondiferous kimberlites in this area including the now closed Kelsey Lake diamond mine are found within the ring dike. Perhaps a similar situation occurs there.

[@paladinkhan]

Geology is cool 😎

[@abhishekash8466]

Highly requesting.. story of Western ghats and Deccan traps formation in India .. Whether Madagascar India split created those mountains or not ..

[@goldenhate6649]

Deccan traps were a seperate event if I am not mistaken

[@rizkyadiyanto7922]

visnu created it, of course.

[@AlpakaWhacker]

Looking at satellite maps, there appears to be maybe what looks like 4 other similar looking structures in Madagascar in addition to the ones shown in your video

[@chazmiseroy9459]

There are three of those round structures in the center of Madagascar. If you zoom into the mountains around them you will see what looks like tree branches. Giant Cedar like petrified tree branches. The giant circles are giant tree trunks of trees that were cut down. They have nothing to do with lava. Zoom onto the mountains around the structures. You will see hundreds of branches and leaves. Zoom in and see for yourself.

[@jordisalvadobuque1803]

Thanks. How many misteries has geological movements around the world 🌐!!! And Madagascar is one of them..🌐

[@mfaizsyahmi]

It's Wall Sheena from Attack on Titan.

[@StarScrier]

So no physical examination was done to find igneous rock, to verify this hypothesis? These types of formations can also be made from extreme examples of lightning.

[@perrymaskell3508]

Could you please comment on the Chrissies Meer group of pools on the Easter / Central part of Mpumalanga province in South Africa? I'm convinced they are small impact craters due to their odd alignment, all form one incident.

[@tornadoclips2022]

When’s the next update on the campi flegrei super volcano? I heard scientist telling citizens in Naples to evacuate

[@souravjaiswal-jr4bj]

Not every eruption of a supervolcano is VEI 8. The eruption is inevitable but lacks the magma volume for VEI 8 or even 7. Most likely it will be VEI 5. The volcano is heavily studied, we would know months if not years in advance of an eruption.

[@tornadoclips2022]

@@souravjaiswal-jr4bj that’s true but even a VEI 1 would be disastrous in the area

[@El3andro]

The update is that recently a magma reservoir was discovered in just 5km depth. So far, scientists assumed only other fluids at that depth. Seems like the earthquake crisis of 1982-84 was also triggered by uprising magma. Those new results are based on a new study that analyzed all micro earthquakes from the past and were able to get new results. I just read about this in a volcano blog yesterday

[@christopherlee627]

I wonder if a feature in Queensland, Australia, might interest you as it appears to be very similar. Having seen it on google earth I've wondered if it's an impact crater or of volcanic origin? I'd be interested to see if you think Mt. Goondicum is of similar origin to the Madagascan features?

[@donutarmageddon7975]

Oh, cool, it's an Alan Smithee joint.

[@genericalfishtycoon3853]

Sounds like something I'd pick up at the dispensary lol

[@TheSpiritombsableye]

Do you mean, Madagascar moved north from it's original location of Marion Island? 2:40

[@LuisAldamiz]

Cool. So that also explains the Eye of the Sahara? I must remember that phrase "domed anticline plus erosion" to slap into the face of the next one who claims it is Atlantis. TY.

[@CricketsBay]

I think Geology Hub made a video explaining the Eye of the Sahara. And, yes, it is a domed anticline which has been eroded.

[@ClariNerd]

So basically the same thing as Pawtuckaway or Ossipee.

[@ilovecatsijustlovecats3944]

These are stumps of trees cut down before the flood

[@zulea7883]

Didn't someone do a series on KZbin visiting this?

[@m4a4sherman]

Can you do a video on the Ossipee Mountains ring dykes?

[@peronik349]

I heard (in a documentary on the history of England!) that Hadrian's Wall was partly built on a geographical and geological feature of this area which would be almost volcanic in nature! what is your opinion

[@davidcranstone9044]

The central part of Hadrian's Wall is built on the outcrop of the Whin Sill. A sill is a layer of igneous rock that was intruded between two layers of the preexisting 'country rock',and the Whin Sill is one of the largest known extending from Teesdale almost to the Scottish border. Since it is very hard, and dips quite steeply to the south in the Hadrian's Wall area due to later earth movements, it forms a ridge with a cliff-like scarp edge facing to the north. The perfect line for Hadrian's Wall!

[@rafaelcerrajerogimenez5907]

Possible... meteorith.. impacts.. 😮

[@Kerbhunter_Alex]

Where andn when will the next flood basalt be? Is there anything known?

[@Miparwo]

Could the Sea of Japan be a caldera resulting from a meteorite impact at its antipode?

[@rizkyadiyanto7922]

pacific ocean is a caldera.

[@VentureNW]

So the Eye of the Sahara isn't Atlantis? 😄

[@Shadoweknows76]

The remains of an ancient tree stump.

[@pasqualelapelosa7365]

I hope you are being sarcastic

[@johnmudd6453]

Aaaaarrrrrggghh the commentary !

[@ArmourProtected6-10]

WHY are the ads so long? Geesh.

[@pyalot]

The quintessential armchair geologist.

[@alanthecat59]

😻😻😻😻😻😻

[@FenderMinerals]

We both enjoy your videos and analysis very much. We have a request. We find the computerized voice much too monotone. It needs more inflection.

[@davidcranstone9044]

It is not computerised, it is his real voice. And the reason it sounds a bit odd to some people is because he is autistic - he explains that in the intro to his Iceland drone flight livestream about a month ago. If you really can't stand his voice, mute it and follow the transcript.

[@k.c1126]

This looks like a structure I saw a video about a couple of months ago...

[@foowashere]

On Vox.

[@k.c1126]

@@foowashere You are right! kzbin.info/www/bejne/nmWVgomcp7qJfNksi=Jb6V-WXbUbsmNCQo

[@pansepot1490]

So, basically a pimple.

[@solarnaut]

Well, yeah. . . OBVIOUSLY ! . . . I mean even I cudda told ya that ! . . . ummm, I mean, now that I've seen the video. B---)

[@danbunge9787]

Why are you whispering?

[@rand49er]

Narration makes it unwatchable. Sorry.

[@seanjoseph8637]

AI narration sucks.

[@66kbm]

Diamonds were not found in the Netherlands.................Too sandy. LOL

[@TheSpaceEnthusiast-vl6wx]

Thanks as always! It is always good to discuss these kinds of features, especially this unusual formation. I wonder if it has a name yet.