Volcanic New Zealand | Part 1: A Violent Past | Free Documentary Nature

you wouldn't suspect it but this is new zealand it's hardly what most visitors might imagine these green islands to look like but this barren landscape in the central north island is one of a handful of volcanic dune fields on the planet tayana tapu enchanted sands [Music] it appears to be a desert in fact the region receives more than two meters of rain annually entire forests grow out of enormous black sand dunes any rainfall quickly drains through the gravels it's one of the rarest ecosystems in the world it's the domain of mount ruapehu fierce winds and volcanism constantly shift the sands yet somehow life persists in these violent conditions this is a scab weed it traps all that wind blowing dust and ash from the volcano this is the beginnings of dune field vegetation in this volcanic landscape nearby a moss called rachymetrium picks up where the scab weed leaves off and here we have the final stages of succession in this dune field but there's a massive volcano up there and he's sleeping and anytime he can go off and put everything back to ground zero [Music] and then the whole process will start all over again [Music] new zealand owes its existence to a fiery past volcanoes lifted islands out of the sea and generated rivers and lakes from their slopes but the past isn't dead and it's presenting a clear warning that history may soon repeat [Music] [Music] is new zealand's largest active volcano it's found on the central plateau of new zealand's north island [Music] ruapehu frequently erupts and can be massively destructive [Music] holly gabrielson works for the department of conservation what an amazing landscape holly if there's any sign of a volcanic event it's her job to get visitors off the mountain [Music] in winter it's a popular ski resort there can be hundreds of people to evacuate [Music] so when did ruapehu last erupt last erupted september 2007. holly's on the mountain today guiding visiting scientist peter delang in 1996 he witnessed a major eruption and has good reason to be wary on 96 we were driving down the desert road we heard this loud bang and looked over and we could see this big white jet going straight up into the sky the eruption came out of nowhere and was incredibly dramatic an eruption column reached 10 to 12 kilometers into the sky there were massive explosions lava bombs were sent hurtling across the landscape i noticed the eruption plume had just suddenly stopped and i thought that was a bit unusual so i started filming journalist jeff mackley was caught in the drama the next thing there was this huge explosion shook the ground and the next minute there were rocks raining down all around me and impacting the ground ruapehu is one of new zealand's most active volcanoes like volcanoes in mexico city and iceland it has a tendency to occasionally wreak havoc on anyone nearby eruptions have occurred regularly since the 1960s even when it is quiet it is considered to be in a state of minor volcanic unrest i link to several tribes that have interest in this national park we know from our oral histories and since the arrival of people here that the mountains have been erupting throughout that period there's always been in a relationship with the mountains and there's always been that understanding of the formations and how it's influenced the landscape that surrounds us between eruptions a lake forms in the volcano crater fed by melting snow up to 10 million gallons of water can accumulate and if there's an eruption the crater wall breaks in 1953 a massive torrent of water rocks and mud streamed down the volcano slopes dramatic canyons were carved as the debris poured across the landscape isn't that an amazing landscape looks like a giant plows being right through it the deluge traveled over a hundred kilometers leveling everything in its path 24 kilometers from the summit its force was still immense it hit a rail bridge washing it away in seconds just before a passenger train was about to cross 151 people were killed scientists are searching for ways to accurately predict volcanic eruptions mount etna in italy one of the most active volcanoes in the world is a major focus for research volcanic lava contains mineral crystals when it travels towards the earth's surface the crystals shift their composition as their depth changes it's been discovered that when particular crystals appear around 10 kilometers from the surface they signify the arrival of new magma from deep below an eruption is likely within just two weeks crystal analysis also allows us to travel back millions of years and discover the history of a dormant volcano [Music] nowhere in new zealand is more ancient than the remote mountains of fiordland mao te tiroa is one of the area's most prominent landmarks [Music] it's an almost lunar landscape just north of tetidoa the mountains of new zealand's southern alps were formed by tectonic uplift they are at the collision point of the australian and pacific tectonic plates that uplift has created one of the fastest growing mountain ranges in the world [Music] but fiordland is different the rock here was not slowly lifted out of the earth but formed inside a magma chamber under the sea we know the rock has a fiery origin but how and when were these bizarre formations created geologist rose turnbull of gns science is joined by colleague julian thompson they're here because crystal's hidden in the rock may reveal its history [Music] rose turnbull and julian thompson are in search of one of the oldest volcanoes in new zealand dating the age at which these granite rocks crystallized will give us an idea about how long new zealand has been volcanically active and may help us predict future events rose all these rocks how do they get here what's going on well this entire mountain is made of granite which used to be a magma chamber it's now exposed at the surface this granite has natural cracks in it because we're sitting above the snow line the snow and the ice gets into those cracks and over time breaks it down into these boulders that you see littered around the mountain top rose is on a search for rare crystals she hopes will tell her when this extraordinary landscape was formed this is quite nice to walk on this soft sand yeah it looks a bit like a beach sand actually and if you get a bit closer and have a look you can see that it's sparkling and glinting back at us what we can actually see are crystals that used to make up the granite itself that's amazing look at that crystal face what rose is searching for is a little more difficult to find it's a mineral called zircon they'll be here but they're very very tiny they're tenth of a millimeter inside could we just take a scoop of this stuff back or there would be zircon crystals in here but what we really need to do is take a sample of the hard rock that hasn't eroded because then we know that those crystals have come from that piece of rock the unique geology of the area has created an incredible mountain garden the ground is covered in mosses and lichens in many places it creates a thick soft carpet [Music] these plants are known as golden spaniards despite their hard needle-like leaves they're a member of the carrot family [Music] while rose searches for a suitable rock sample julian explores the area the rocks that we're standing on are the earliest evidence of volcanism in new zealand if we go back in our mind's eye to the past this was hot liquid rock deep in the earth maybe 10 or 15 kilometers below the surface incredibly high temperature and under great pressure and that liquid was rising up and some of it would have reached the surface and erupted in enormous volcanoes so when we take samples from these rocks with rose we're going to learn even more about the secrets that they're going to reveal we'll be able to get a really precise date for when these rocks were formed how'd it get on got a nice sample of granite here oh great have a look yeah it's a nice clean face and uh you'll think you'll have the zircons that you want in there absolutely yeah we've got a big enough size here that we should get about a teaspoon of zircon crystals which is more than enough to date it right and so you think that this rock is about 100 million years old roughly and you're going to take a few million years do they go back in time older than that in other rocks can you find them very much older so the older zircon that have been dated uh 4 300 million years old which is only 300 million years younger than the age of the earth so almost as old as the earth just tells us that these rocks can take us right back to almost the beginning of time yeah great isn't it that's amazing building a detailed picture of new zealand's volcanic past will provide a database to predict future patterns of activity [Music] at the nearby university of otago it's time to discover what the crystals from mount tetherua can tell us rose will be using an instrument called a spectrometer okay let's put the sample in it will identify different chemical elements within the crystal sample okay so in my hand i have a zircon mount and within this zircon mount we have several hundred zircon grains the grains have been separated using a high-powered microscope a mold has been placed round them and glue poured in the zircon mount is inserted into a machine and a laser fired through it so now our sample is in the sample chamber and this here is our zircon grain so we're going to have a zap of that zircon green so we're going to put a spot where we're going to fire the laser the laser extracts a grain of zircon the sample is then analyzed by the spectrometer so on the screen here the dark blue line represents the element lid and the light blue line represents the element uranium and the difference between those tells us that this was crystallizing 120 million years ago for the first time the mount tateru eruption has been accurately dated understanding the history of volcanic activity is a vital tool in the quest to predict future eruptions some of new zealand's volcanoes are dormant but many are active mounte was formed as new zealand began to separate from the supercontinent gondwana as new zealand continued east the pacific plate was forced beneath the australian plate melting it this formed magma which rose to the surface at multiple points to form active volcanoes beneath the ocean white island is located just 48 kilometers off the east coast of the north island this relatively youthful volcanic landscape was created over the last 150 000 years the island is constantly monitored frequent eruptions occur harmless looking streams pour down the slopes in fact they're streams of sulfuric acid [Music] two kilometers below the surface is a boiling lake of liquid rock superheated steam and poisonous gases such as hydrogen sulfide pour from vents in the ground many active volcanoes are hidden deep beneath the waves white island offers a unique opportunity to learn what they look like beneath the ocean tectonic plates grind against one another this geological turmoil has created a range of underwater volcanoes it's known as the kermadec arc and runs from white island to tonga it's the longest continuous volcanic chain in the world the study of these deep ocean volcanoes has been the life's work of gns scientist cornell durond cornell is leading a research expedition to explore the brothers volcano in 2012 a nearby eruption more than 1500 metres beneath the surface created a raft of pumice covering hundreds of square kilometers [Music] but cornell and his team are not here to study eruptions they're here to research how volcanoes transport precious metals from deep within the earth to the ocean floor [Music] the expedition has partnered with the woods hole oceanographic institution who have outfitted the expedition with jason a state-of-the-art deep-sea remotely operated vehicle known as an rov for short and capable of withstanding extremes of pressure and temperature above the surface is another story it's cyclone season and the weather has just started to close in cornell and his team are exploring the brothers volcano on the kermadec arc but an approaching cyclone has complicated the expedition so weather for us is a is a big deal um you know again we've tried to build the system as robustly as possible but you're talking about an 11 000 pound vehicle that you're going to put in the ocean on a ship that's moving up and down clearly there's going to be limits to how how much we can operate in that it's more about can you get the vehicle in the water can you get your checks done pull the pin release it from the crane and get it sub c before it gets destroyed by waves underwater an alien world gradually comes into view the very big difference between white island and those volcanoes on the seafloor is the fact that the latter have a lot of sea water sitting on top of them and what that means is when we have very hot hydrothermal fluids and they can be 300 degrees on the seafloor and as they come to the seafloor they mix with ambient sea water which is only about 2 degrees so when 300 degrees meets 2 degrees you get these tremendous chemical reactions and as a consequence of that much of the minerals go off as smoke [Music] when metal-rich hydrothermal fluid mixes with seawater they form strange chimney-like structures they're known as black smokers the chimneys are lined with deposits of critical metals like copper gold and zinc these chimneys represent a potential future resource for mankind for for potentially decades to come and ironically they might even be renewable in the sense that once the chimney falls over or it's plucked off the ocean floor it just grows back so where we have fluid flow you cannot stop these chimneys from forming the conditions around submarine vents combine to create an extraordinary chemical soup in which unique life forms have evolved to be unlike anything else on earth i've seen a lot of the seafloor in my ten years of doing this and a lot of it's pretty pretty dead there's not a lot going on out there and so to come from just mud bottom where there's nothing going on to all of a sudden hydrothermal vents shrimp crabs tube worms this whole colony of life it's pretty pretty amazing and to think that that's probably where life started on this planet and we get to see it firsthand is uh that's that's the best part of the job right there for sure many of these species move abandoning old dying vents for new locations in search of food and habitat we see a number of new species almost every time we dive on volcanoes and some of these species are quite spectacular for example long neck barnacles with their beautiful fronds flapping away what seems like in the breeze so a whole host of animals that we've never seen before on earth are commonly discovered on these volcanoes [Music] but why do so many species actively seek out underwater volcanoes microscopic plant life known as phytoplankton feed the ocean ecosystem it needs two vital elements to survive sunlight and iron until recently scientists didn't understand where this iron came from it's been discovered that underwater vents like those at brothers release fine particles of iron ocean currents carry these particles for hundreds possibly thousands of kilometers the iron acts as fertilizer for phytoplankton creating rich ocean communities this helps explain the extraordinary diversity of creatures around undersea volcanoes every new species we discover is a missing piece in the jigsaw of marine ecosystems by understanding the complexity of submarine life we can monitor change and help preserve the oceans south of white island evidence of oceanic volcanism can be found near the town of oamaru [Music] like white island the cliffs here were created by a submarine volcano dr ben morehouse has been studying the area to learn more about its volcanic past the coast here is famous for a strange phenomenon known as pillow lava but why would these formations exist only here and not on white island if you want to see pillow lavas this is a world-class spot to do that these are actually little bits of lava that are coming out of the ground underwater and as they're squeezing out that water around it is turning to steam it's in its own little bubble which allows it to form this beautiful spherical shape the outside of each pillar has a really thick black layer and that's where the crystals are actually forming really really quickly because they've been really hot and all of a sudden they're in contact with cold water and the inside that's actually cooling a lot slower which is creating that color difference the pillows are surrounded by white limestone either the lava erupted into a mixture of shells and water or shells trickle down to fill in the gaps as ben moves further along the cliffs the rocks reveal more of their genesis after the pillow lava finished erupting around 38 million years ago we actually had a period of carp so shallow water above the top of the volcanic man would have been perfect for the buildup of coral reef and for marine organisms to thrive [Music] reef buildup is seen as an orange layer [Music] moving up the cliff a thin brown layer reveals a relatively small eruption occurred around 36 million years ago a coral reef then developed before another period of volcanic activity [Music] just an hour's drive south from oamaru is an entirely different landscape [Music] the area surrounding dunedin was created by volcanism over more than six million years of constant activity like kilauea in hawaii dunedin's landscape was created by a shield volcano with layers of lava building up like flowing honey [Music] these remarkable rock formations are called the organ pipes they're a type of pillar lava formed when lava cools and contracts the otago shield volcano oozed rivers of lava out of multiple centres producing enough material to bury the city of san francisco beneath more than a kilometer of stone [Music] dunedin's natural harbour was formed as the volcano's crater flooded it's a terrific asset for humans but is an even better resource for its winged residents [Music] albatross spend 85 per cent of their life at sea some live more than a year on the ocean before returning to land throughout the rest of the world albatross are only found on small offshore islands but here these sheer and unusual shaped cliffs provide perfect conditions for the world's only mainland albatross colony albatross need relatively flat terraced areas to build their nests [Music] with a wingspan of more than three meters albatross take flight by catching the breeze like a hang glider at the otago peninsula built a tremendous mountain from the ocean floor but further inland volcanoes blasted deep craters in the earth the lakes that form these craters are called mars when magma collides with groundwater they explode blasting out a massive hole in time the crater fills with water to form a circular lake if a mar dries out it becomes a treasure trove for fossil hunters a team from new zealand's otago university is headed for folden ma [Music] the team leader is professor daphne lee today the dried out crater is a small quarry every trip to voldemort is exciting because it's like going on a scientific treasure hunt we have no idea what we're going to find and almost every time i or the students that i bring with me find something completely new to science [Music] what we're going to do now is get the gear out and then off you go and we'll see what you can find look out for especially for things like fish and leaves are pretty obvious but the insects are usually tiny but if you find anything important they actually need to be taken back to the lab and then we'll do careful stuff under a microscope okay so let's get to work because mars are lakes formed in volcanic craters they have a rim around them [Music] the team can be sure what they find either lived here or was blown into the lake in this case we've got a lake that's filled with diatoms which were the little plants living in the upper waters of the lake and as they died they would sink quietly down to the bottom starting 23 million years ago diatoms created over 120 meters of sediment on the lake floor there's no current in the deep lake so very little oxygen reaches the bottom creating perfect conditions for preservation this is the only fossil lake more than one or two million years old and the whole southern hemisphere that has got this kind of sediment preserved like this [Music] the rock is so soft that a chainsaw can cut through it each layer in the rock represents plant sediment deposited over one year allowing very accurate dating there was once another 100 meters of sediment on top of where the team's working over the last 22 million years it's gradually been eroded away what daphne's team will discover is anyone's guess [Music] i've got the leaflet serrated edges here daphne how have you it's in two pieces though oh that's a pity never mind you've got both the bits i think we can probably put it back together again daphne lee and her team are on the hunt for ancient fossils inside an extinct volcanic crater the most common fossils that we find are leaves and often there are new species and we name it it's got nice rated edges on it so little teeth around the edge we don't have many leaves like this in new zealand today the interesting thing is about half of them are from plants that we don't have growing in new zealand anywhere 23 million years ago it was really warm and then maybe about 10 million years ago the climate started to cool and then we went into the ice ages and we had these warm cool warm cool periods and these plants just couldn't cope [Music] i think i got a bit of a fish oh let me have a look just in there oh yes you're right yep yep i can see its tail and it's probably another galaxy you know one of the little white bait and they must have been swimming around in the top part of the lake and then they just die and just quietly sink to the bottom and it's been lying there for 23 million years until you split split it but it's worth taking back so put it in a bag and the party and the counterpart and we'll take it back to the lab that's good thanks we've had quite a good day we found quite a lot of leaves we had one little fish i was really hoping for some whole fish but um that's the way it goes and unfortunately we haven't found a single insect they are one of the really special things for the site the unique fossils found at folden ma are stored at the university of otago daphne's colleague uber kaufas has made a detailed study of the fossil insects vodma is an amazing site when i went there the first time 10 years ago i saw all these nicely preserved leaves and flowers in pollen and i thought there was a forest round so there must have been insects when work first commenced at folden ma just six fossil insects over two million years old were known from new zealand since then almost 500 have been identified weevils have long legs as they settled to the floor of the lake they fell on their sides other beetles have shorter legs so as they drifted to the bottom they landed on their belly or back [Music] this could be the first fossil bee ever discovered in new zealand and on some of the specimens even colour is preserved insect fossils provide valuable clues as to the type of plants they lived alongside they're also vitally important in helping to track climate change over time this one's lifting off daphne and her team carefully examined the latest batch of rocks this is the really exciting bit we go out and we collect some rock and we split it and we have no idea what we're going to find there we go each layer offers a window into one year of earth's ancient past look at that okay there we go that's pretty nice we've got an entire little fish here and these belong to the family galaxity these are the oldest examples of white bait fossils that anybody's ever found anywhere in the world [Music] it's possible that the 130 meter deep sediment might even contain crocodiles and giant birds such as the new zealand moor most times when we're fossil hunting we find something we've never found before so yeah that's pretty exciting stuff [Music] fossils aren't the only window into the past new zealand was once the site of one of the most devastating eruptions the world has ever seen could it occur again [Music] to find clues scientists paul williams and his team are heading deep into the waitomo caves [Music] for geologist and maori historian dan hakuroa it's a journey that helps tell the story of his people the name of this place is the dean of the dogs legend has it a chief was passing and some dogs came out as if from the underworld he chased the dogs down he captured them and he took their coats to create a dog skin cloak now at that time a dog skin cloak was said to give the holder power now still the dominant people of the area today new zealand was the last land mass to be inhabited by humans therefore maori history of the islands is limited to less than a thousand years there were no witnesses to any prior eruptions [Music] the team is here to search for evidence of new zealand's ancient mega eruptions [Music] okay done yeah here i come speleothems are stalactites stalagmites and other features that form in caves over millions of years ash from volcanic eruptions lands on the ground above the roofs of caves over millennia the ash mixes with rainwater seeps through the rock and forms icicle-like structures by studying the layers in these rock forms scientists can obtain details about new zealand's volcanic past these rock formations can also reveal what was happening in the prehistoric world above oh these are nice scallops what's that scallops and the little eddies dissolve these features out and the steep face gradually works upstream it's all backs up stream and where the steep slopes come together they make points and that shows you the direction in which the water was flowing how long would the water come through here how long ago well if you if you look at the stream down below it's about three or four meters below us and the rate of incision here is about a meter and a half every thousand years so we're really talking about just a few thousand years ago [Music] kinks on some of the structures indicate a major earthquake possibly caused by a volcano that has resonated through the cave [Music] the lower chambers of the cave are a library of new zealand's volcanic history speliofms are a goldmine of information by studying ash deposited in their layers we can date significant eruptions to within 30 years oh look at that kate a a rock breakdown a rock fall going as far up as you can see right up to the black void that's it it's a sort of thing which could have been triggered by an earthquake after a volcanic eruption there's been over 100 years of of tourist guiding in this cave and when they first came in they discovered in some of the far corners some of the corey some of the human remains of my ancestors now these were interred here because dark places such as caves are associated with the underworld they are associated with with the dead i'd say this rock was about the same age as the one we were looking at before oh this is a lovely exposure of some of the volcanic ash underground kid so what happened we saw that rock pool and when it came down it crashed against the wall of the cave and blocked the stream [Music] and this is some of the sediment that was carried by the stream but the really interesting thing is this really gray looking layer coming through here and the white layer above it and you can see how very finely banded it is and this one is the orinoi and we know it's 25.4 000 years old a hundred kilometers away above ground is lake taupo it's actually the flooded caldera of a super volcano the uruanui eruption from this location was the world's most recent super eruption vast quantities of rock were propelled into the air falling from the atmosphere to cover much of the central north island 18 centimeters of ash was deposited a thousand kilometers away [Music] debris reduced the intensity of sunlight cooling the temperature and perhaps triggering a volcanic winter we're talking about enormous geological processes because we have records in speedy themes which we can date for at least 500 000 years if we can identify when the earthquakes occurred and we get an idea of how big they were and can we do this over very very long periods of time then there is the potential to build up by far the best record of earthquake frequency in new zealand as our knowledge of new zealand's volcanic past increases we can more accurately predict its volcanic future we may not be able to accurately say when new eruptions will occur but it's only a matter of time before destruction and creation come to new zealand again [Music] you

Channel: Free Documentary - Nature

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Keywords: Free Documentary, Documentaries, Full documentary, HD documentary, documentary - topic, documentary (tv genre), nature documentary, Free Documentary Nature, Nature, Volcanic New Zealand Creation and Destruction, Volcanic New Zealand, New Zealand, New Zealand Documentary, Volcano Documentary, Volcanism, Volcanism Documentary, Paficic Ring of Fire, Volcanoes in New Zealand, Nature of New Zealand, NZ Documentary, Volcanic

Id: f2ZxJhkK9xw

Length: 44min 13sec (2653 seconds)

Published: Wed Sep 21 2022