The Geologic Oddity in Australia; Hanging Rock

[@likegirlidk]

I always really appreciate the little diagrams you draw for these videos, really helps

[@DaveTexas]

I love the movie Picnic at Hanging Rock. So creepy and unsettling. I really wish I’d visited Hanging Rock when I was in Melbourne many years ago, but we opted to drive out along the Great Ocean Road to see the rock formations along the coast instead. We should’ve kept the car for another day…

[@nevillebartos2858]

There you go. I always thought it was somehow connected to Mt Macedon, an ancient supervolcano virtually next door, but it sounds like Hanging Rock came a lot later. It's certainly an eerie place.

[@ImpendingJoker]

If you've never watched OZGEOGRAPHICS you really should. He deep dives a lot of Australian geography. Y'all should do a collab.

[@S-T-E-V-E]

Could you do a video explaining the different types of Lava and how they form?

[@garywall5769]

Love the gratuitous Roo photos. Your channel is educational and adorable.

[@chrisantoniou4366]

I live quite close to Hanging Rock or Mount Diogenes as it was once called, and knew that it was a "volcanic plug" but little else. Thanks for providing the details and the diagrams. By the way, Hanging Rock is an easy to climb to the summit and great to photograph.

[@RichardFelstead1949]

I lived at Woodend in 1956.

[@BuzzYear10]

Hanging Rock is known by many traditional owners as Ngannelong and it's an important site for the Dja Dja Wurrung, Woi Wurrung, and Taungurung clans. If anyone wants to visit proper respect ought to be paid to this history.

[@kalinystazvoruna8702]

Thank you for this information.

[@lioneldemun6033]

I hope the visitors don't trash the site

[@RichardFelstead1949]

Thanks for taking my suggestion. I lived at the nearby town of Woodend in 1956 only a few miles from HR.

[@TheSpaceEnthusiast-vl6wx]

Thanks as always. The volcanism chart of Australia at 1:30 shows how rapidly the continent has moved over the last 33 million years. I wonder if Australia could match India's fastest movement speed, which was 20 centimeters per year!

[@outlawbillionairez9780]

Australia has moved 4.9 feet since 1994. Causes problems with GPS. I tried to find out the total distance this continent has traveled, with zero results. 🌋👍

[@kalinystazvoruna8702]

@@outlawbillionairez9780 Maybe that's a question for GeologyHub?

[@Dragrath1]

While I think you are likely accurate in this case The Cosgrove hotspot does appear to be relatively stationary with respect to these deep mantle features since there doesn't appear to be any relative drift among the Australian hot spots relative trajectories so yeah Australia is hustling along. I would however like to emphasize that in general while it's tempting to assume all that motion of hotspots is due purely to plate motion and for all I know that may actually be the case here but I also know there is evidence that not all hotspots are equal and there are at least a few hotspots where this method of reconstruction can't reproduce all the hotspot tracks without some degree of relative motion of hotspots with respect to the crust and upper mantle as a whole. Seismic tomography does seem to support this more nuanced picture is that hotspots appear to be linked with deeper structures within the mantle such as the low sheer velocity provinces floating on the outer core at the core mantle boundary, subducted slab walls and or stagnant slabs. Hotspots also vary in the temperature and chemical composition of the magma relative to their source of material. Plumes rising from subducted slabs deep into the mantle tend to have weird chemical compositions and be more ephemeral on long timescales. The other kind of hotpots are thermal ones which rise from thee core mantle boundary some seem fixed but at the very least the Galapagos and Icelandic hot spots can't be purely explained without some relative motion with respect to the crust and mid ocean ridge systems i.e. they have moved west and south respectively but these interestingly enough appear to come from plumes which while associated with the deep lower mantle don't appear to reach the core mantle boundary so perhaps this explains their relative drift? In some sense these seem a bit of a combination of the two "pure" hotspots. Anyways I digress its more a matter of this being still an active field of research. Given that slab pull is believed to be the dominant driver of plate motions I wonder if that speed might have something to do with the southeastern sections of the Sunda trench starting to subduct the Australian continental shelf representative of the earlier stages of slab failure with zones further to the southeast showing more advanced progression leading up to and including the eventual obduction of the formerly oceanic volcanic arc onto the continent as has already happened with New Guinea. The multiple layers of subduction zones piling up in that part of the world could be quite important in this overall picture as their relative motion could be compounding onto each other. In this broader picture Indonesia is reeling in Australia before the more buoyant continental crust can eventually overcome this downward pull and break the slab. This leads me to suspect that the rate of Australia moving North is probably pretty unlikely to be constant

[@ravakahn]

I think the Indian Plate moves about 20-30mm a year (not cm - easy mistake) and the Australian Plate moves about 60-70mm per year. It's one of the fastest moving plates in the world and causes problems with GIS and GPS. Every few years these systems need to be updated with Australia's latest movements, with the latest update being in 2020. I think it would be hard to determine just how much the Australian Plate has moved over the coarse of its existence as @outlawbillionairez9780 has tried to find out, mostly because the western part of Australia is one of the oldest landmasses in the world, being something like 2-3 billion years old.

[@TheSpaceEnthusiast-vl6wx]

@@Dragrath1 Thanks. I have noticed a possible discrepancy with how much continental crust existed at 2.5 billion years ago and depictions of that time period, such as Algol's History of the Earth video. I have read that as much as 80% of the extant continental crust was produced by that time, but the aforementioned video shows a smaller amount of continental crust. Does this mean that there are areas of continental crust older than 2.5 billion years ago that we don't know about? Of course, Algol admitted that before 1 billion years ago, there are huge uncertainties with how the continents were positioned.

[@johnyoung1128]

Thank you for doing this video, I’m always keen on learning about Australian and particularly Victorian volcanic features.

[@heidischulze2920]

topic request: the Logudoro volcanic field and its beautiful landscape and caves

[@rchiribogar]

Thank you!! Have you ever done a program on Elephant Rocks in Missouri??

[@Stickiedude]

Whoooo!! Aussies represent! Can you do a vid on Wilpena Pound? Or Cooper Pedy? Just more Australian stuff. Please.

[@EarthquakeSim]

The sound quality is best! ☺️ also, I love the animations you’re making to describe geologic processes

[@sonycans]

Thank you for adding this feature. I always thought that this was volcanic. This is my home state.

[@WoundedEgo]

The way the eruptions leave visible indicators of long time was new to me, and very fascinating.

[@adzz8012]

Between you and ozgeographics ive been getting my earth sciences fix. Very informative :) Edit typos lol

[@relwalretep]

Picnic, anyone?

[@zacharyantle7940]

God that movie is gorgeous

[@kalinystazvoruna8702]

@@zacharyantle7940 Fantastic movie!

[@lindaj5492]

Cue scary music ….

[@AJWRAJWR]

Is that you, Miranda? 😮

[@GrumpyMeow-Meow]

She’s a Botticelli angel!

[@kalinystazvoruna8702]

"Picnic at Hanging Rock" was a 1975 mystery movie by Peter Weir, based on the book by Joan Lindsey. "Although the events depicted in the novel are entirely fictional, it is framed as though it were a true story, corroborated by ambiguous pseudohistorical references. Its unresolved conclusion has sparked significant public, critical, and scholarly analysis, and the narrative has become a part of Australia's national folklore as a result. " (Wikipedia) Awesome movie! Nice to see the actual place where the movie was filmed and learn more about it's geological history.

[@NGC-catseye]

I really enjoy the original movie, it’s an all time classic,. But did you see the new series they made? It was pretty good 😊

[@lioneldemun6033]

Isn't the film " the sinking of the Poseidon" also framed as if it was a true story? I wonder why no filmmaker has made a 🎥 fiction inspired by the tragedy of the Batavia

[@kalinystazvoruna8702]

@@lioneldemun6033 Aren't you referring to the movie "The Poseidon Adventure"? I saw that movie in the theater in 1972. It was never billed as being "a true story". It was always fiction, considered to be a "disaster movie" like "The Towering Inferno" (which I also saw in the movie theater in the 1970s) or "Jurassic Park". Nowadays, with conspiracy theories and just plain deliberate misinformation out there, I wouldn't be surprised if people suddenly believed that "Superman" was real, as was "Batman", or any other fictional movie. The ability of people to allow themselves to be fooled just astonishes me. There *is* a difference between "suspending disbelief" and outright gullibility.

[@lioneldemun6033]

@@kalinystazvoruna8702 then it's me ! I was young and naive when I watched it,and I thought it had actually happened!

[@kalinystazvoruna8702]

@@lioneldemun6033 Well, the writer certainly tried to make it seem as if it was real because she included a number of "articles", purportedly to be "real" in her novel to fool people. The movie kind of did the same thing and, like you, when I first watched it, I thought it was a dramatization of a real event. Just goes to show you that the saying, "Don't believe everything you read in the newspapers (modern version: everything you read on Social Media or the Internet), is true," needs to be kept in the back of one's mind while reading/watching something.

[@GreatDaneLoverz]

Please do a video on mammoth springs in Missouri

[@Celeste-in-Oz]

Words can’t quite describe the feeling you get walking around it. It’s a beautiful place, but feels dangerous. I assume that’s only because I knew the story of the girls’ disappearance.

[@travelphotos7662]

The author did a lot to maintain that mysteriousness when giving interviews. She never straight out denied the story being true. She gave nebulous, circular answers. I grew up being told that it was a true story and it was only late into my teens did I start questioning it and hearing that it was entirely fictitious. I've yet to visit the rock formation but have visited areas close by.

[@sciencetroll6304]

I went there with a carload of punks in a ' we rule the world ' mood. We got there and all went quiet. There is a definite sense of ancient evil, that doesn't come from the movie..

[@sirskidney7998]

Awesome Mr. GH! It’s a really beautiful spot and I suggest that you should visit here when you come down to see us. Many thanks.

[@Nightscape_]

Cool information. I am listening to the Men at Work/Colin Hay discography right now. Will have to Listen to Youth Group's as well now too after this video.

[@Dragrath1]

As for hotspots I feel the need to emphasize that we do have evidence that they have their own intrinsic motion in addition to the movement of plates. The Galapagos and Icelandic hot spots are both good examples of this as their tracks can't be reconstructed by plate motion alone without accounting for the relative motion of the deeper mantle sources which feed them.

[@outlawbillionairez9780]

Is the viscosity of lava determined more by temperature or by what type of material it's made of?

[@Anuchan]

Viscosity follows composition. Felsic rock, high in silicate, is highly viscous and is explosive, while mafic rock, low in silicate, flows smoothly.

[@Dragrath1]

To add to what @Anuchan said its a bit of both effects with the dominant component generally being the process known as crystal fractionalization where minerals precipitate out of cooling magma as the magma reaches those minerals freezing point which changes the composition of the magma. Notably Silica has a much lower freezing point so it stays molten until much colder temperatures, especially when combined with water, and as it has a much higher viscosity than the other major constituents of magma this makes colder magmas really get more viscous. The incompatible elements from crystallization processes also happen to concentrate in the remaining melt and thus the remaining magma gets proportionally more gas rich and thus more explosive. The good news is thanks to the release of latent heat as minerals freeze out and precipitate it tends to take a log time for magma to cool especially for larger bodies of magma giving more time for gases and mounting pressure to escape from the melt. That said even without crystal fractionalization hotter magmas have a somewhat lower viscosity letting them flow further and faster. On that note I have learned from this years geology lecture series posted on Nick Zentner's KZbin channel that sometimes in the "right" err wrong circumstances i.e. the last Taupo super eruption you can get convective heat mixing which moves that heat and volatile rich material away from the zone of crystallization which allows for very rapid crystallization to occur on timescales of decades to centuries far too short of timescales for volatile venting and small eruptions to be able to release that building pressure. This helps explain how you can get these enormous super eruptions and emphasizing the importance of these chemical phase transitions on the resulting volcanism.

[@WDGFE]

This reminds me… Have you ever done a video on the “Needles” geology in the South Dakota Black Hills? I was absolutely fascinated with this area when we visited, last year. One other suggestion (from that same trip) might be the Sandhills of Northern Nebraska.

[@louiswright8282]

I know you probably won't reply, but could you do a video on Bradgate Park in the UK? It was a former volcano long ago, and you can still notice the calderas rim, although it has heavily eroded away over the millions of years.

[@davidcranstone9044]

Volcanic rocks yes, but I don't think an actual volcano at least not within Bradgate Park. The Wikipedia article is a good one so far as I can tell. It is part of Charnwood Forest which is a fascinating landscape of late Precambrian volcanics and metasediments exposed as hills between valleys over Triassic desert deposits - in other words those hills originally rose above the Triassic desert and are being re-exposed by erosion of the softer Triassic rocks between and around them. At least that's what I learned when I lived in the area 40 years ago, interpretations may have changed since.

[@Dragrath1]

@@davidcranstone9044 Hmm its probably a bit more tricky as from what I have read it like most of the British Isles along with other areas such as much of France highly warped/metamorphosed parts of Germany the Iberian Peninsula(including much of Morocco) New England and the Maritime Provinces were all part of Avalonia the large mature volcanic archipelago complexes which ultimately got smashed together during the construction of Pangaea. Avalonia's history as an oceanic volcanic arc complex stretches back to the late Neoproterozoic some 700 million years ago and the archipelago persisted out in the ocean for most of the Paleozoic prior to getting smashed up between Baltica Laurentia and Gondwana as they formed into Pangaea. Also note that the 3 major chunks of Avalonia effectively represent the pieces of Avalonia which Eurasia North America and Gondwana respectively took when the archipelago served as the weak point along which Pangaea broke apart. This long and storied tectonic history means that lots of things over large periods of time all got mashed together into fairly close proximity. Just look at the mess that the modern Indo-Pacific is to get an idea of just how complicated such archipelagoes can get before the continental pile up. Edit in case this wasn't clear enough I'm saying both aren't necessarily mutually incompatible it would be interesting to see what a comprehensive expert opinion on the region would look like.

[@TonysGemDesignswithGCS]

A suggestion - how about the other igneous rocks - the plutonic. Especial their role in sources for metals and/gems.

[@fieldo85]

Have you slowed down your speech and practiced pronunciation? It’s much better then your old videos. Really appreciate it. Keep up the amazing work mate! ❤ Cheers!

[@gandfgandf5826]

Nice place for a picnic.

[@thelastvulcano8821]

Plz make vidio about Ngelanggeran extinct vulcano/supervulcan

[@chazzychanz]

Have you done a video about an ancient extinct volcano which is located at Nglanggeran, Gunung Kidul, Yogyakarta, Indonesia yet?

[@alokprakashdas9837]

I was surprised when heard about it's origin from mantle plume .....❤❤❤Nice ......really volcanic features are very dynamic though

[@matthewmarmont4103]

Great vid, can i request you do mt stuart/ the pinnacles in Townsville queensland Australia, i would lov to know if they are volcanic, and /or how they formed, magnetic island would also be of interest, thanks, love your work.

[@nathanwilson5789]

Love your work! You are my favorite channel. Can you explain how the canyon formed between Snowflake and Holbrook, Arizona? Silver Creek is so small but it originates from a very steady spring. Was it erosion or something catastrophic? It's a beautiful canyon.

[@randydewees7338]

I missed the "hanging" part - what hangs there? I mean, I expected some block or something that is "hanging" in some inexplicable fashion. A yogi block, so to speak.

[@kalinystazvoruna8702]

It looks like the rocks are just "hanging" there.

[@Arational]

Good place for a picnic

[@brucekuehn4031]

I have noticed that you’ve been adding in a red lava lamp as footage in some videos lately. I’m no expert, but does that globular liquid that floats and then sinks again bear any resemblance to actual lava? Invented in the 60s, I’m old enough to remember when the lamps first came out. Brings back memories of old head shops with black light posters, tie dye shirts, strangely shaped pipes and incense burning.

[@RoseNZieg]

I'm stunned the Hotspot hasn't been located.

[@michaeldeierhoi4096]

But it has or at least it is suspected to be now just west of Tamania as Geo hub explains 1:18----1:34.

[@compellingpeople]

is there rock climbing or bouldering there?

[@Sarah-gw3ng]

The sulfur that dumped from a train into Yellowstone River recently, could it make reactive steam that could explode as in Hanging Rock?

[@NGC-catseye]

And,,, cue the panpipe music 🎶

[@NeuroKytsh]

yayy a video about my state!!

[@wkrpaz5620]

Just like devil's tower in Wyoming

[@hereticpariah6_66]

We have a "Hanging Lake" here in Colorado.. ....oh, and *First,* i guess...

[@lioneldemun6033]

Anyone here watched the Australian film " Picknick at Hanging Rock"? Such a strange atmosphere in that film....

[@brianedwards7142]

Miranda! MIRANDAAAA! 😉

[@NGC-catseye]

🦢

[@hypercomms2001]

A favourite place of mine….

[@slobodan888]

What about the 'Remarkable Rocks' on Kangaroo Island?

[@satanofficial3902]

When the Earth is properly displayed with the South Pole at the top, Australia is the Land Up Over. It's a topsy-turvy world when maps always have the North Pole at the top. It's way past time for things to stop always being upside down. Regarding the solar system from the southern ecliptic is the correct view.

[@satanofficial3902]

"The quickest way to Melbourne is to take the road to Bamaga." ---Old Australian Proverb

[@satanofficial3902]

When is Northern Territory going to get a REAL name? Calling it North Australia would be so cliché as there are already South Australia and Western Australia. My vote would be to call it Slartibartfastland in memory of Slartibartfast designing the planet in the first place for the sake of pan-dimensional hyper-intelligent mice. It's because of Slartibartfast that Australia even exists.

[@captainiceberg8637]

Please do a video on symon’s yat

[@kaoskronostyche9939]

cool

[@grassnothing1631]

hello

[@yt.personal.identification]

Picnic anyone?