Les Scientifiques Viennent de Découvrir le Plus Grand Réservoir Souterrain de la Terre

Sympa

Saviez-vous qu'il y a un immense océan souterrain caché sous nos pieds ? Les scientifiques viennent de découvrir ce qui pourrait être le plus grand réservoir d'eau souterrain de la Terre, enfoui à des centaines de kilomètres sous la surface. Cet océan caché n'est pas comme ceux que nous voyons : il est piégé à l'intérieur d'un type de roche spécial appelé ringwoodite, qui retient l'eau comme une éponge géante. En fait, il pourrait y avoir trois fois plus d'eau là-bas que dans tous les océans de surface réunis ! Cette découverte époustouflante pourrait changer notre compréhension du cycle de l'eau de la Terre et de l'origine de l'eau de notre planète. Qui sait, peut-être existe-t-il encore d'autres océans cachés qui attendent d'être découverts en profondeur ?  Animation créée par Sympa. ---------------------------------------------------------------------------------------- Musique par Epidemic Sound https://www.epidemicsound.com   Pour ne rien perdre de Sympa, abonnez-vous!: https://goo.gl/6E4Xna​ ---------------------------------------------------------------------------------------- Nos réseaux sociaux : Facebook: https://www.facebook.com/sympasympacom/ Instagram: https://www.instagram.com/sympa.officiel/  Stock de fichiers (photos, vidéos et autres): https://www.depositphotos.com https://www.shutterstock.com https://www.eastnews.ru ----------------------------------------------------------------------------------------  Si tu en veux encore plus, fais un tour ici:  http://sympa-sympa.com

Transcript

00:00Researchers have discovered the largest water reservoir in the Cascades chain, in Oregon.

00:06Hidden underground, it contains a volume of water more than double that of Lake Mead.

00:12To be precise, it contains at least 81 cubic kilometers of water,

00:16which is the equivalent of nearly 162 billion bottles.

00:20Due to a bottle per day, it would take you about 484 billion years to come to an end.

00:26It is therefore a surprising war that this discovery arouses so much enthusiasm.

00:30Spreading over about 1,100 kilometers, from Northern California to British Columbia,

00:35the Cascades chain houses the largest aquifer in the world.

00:39The high Cascades, located in Oregon, are made up of more recent volcanic rocks,

00:44aged about 8 million years, while the western Cascades, much older, date back 45 million years.

00:52They are distinguished by their deep canyons.

00:55Researchers have looked at the transition zone between these two formations,

00:59in order to analyze the circulation of water within the rock,

01:02and to study the evolution of volcanic processes over time.

01:06As part of this study, they measured the temperatures of the rocks at different depths.

01:11It was thus that they made the discovery of this immense underground aquifer.

01:16In principle, the temperature of the rocks increases with the depth,

01:19because they are close to the earth's core.

01:22However, in some areas, they remain surprisingly stable, even at great depths.

01:27This phenomenon indicates the presence of water circulating through the rock and cooling it.

01:32In other words, the Cascades act like a natural water castle,

01:36retaining and then gradually releasing water towards the rivers.

01:40These geological discoveries are of great importance for two reasons.

01:44On the one hand, they reveal an underground water reserve

01:47likely to become a strategic resource for the future.

01:50However, its evolution and its ability to resist environmental transformations remain uncertain.

01:56It is therefore essential to carry out in-depth research

02:00in order to ensure efficient and long-term management.

02:03In addition, volcanic activity is also influenced by this phenomenon.

02:07When water infiltrates deeply and reaches the magma,

02:11it evaporates instantly,

02:13generating extreme pressure that can cause explosive eruptions.

02:17A better understanding of the volume of water retained in the rock

02:20would allow us to anticipate these eruptions and assess the risks they pose.

02:24Although this discovery is fascinating, it still raises many questions.

02:29For example, how does this water circulate in the volcanic rock?

02:33What part of it is actually exploitable?

02:35This reservoir is fed by rainfall and snow melting.

02:39A succession of dry years could affect both water supply and the stability of the volcano.

02:45Researchers are working to better assess the extent of this phenomenon

02:48in order to ensure responsible management.

02:51Let us now look at the chain of waterfalls, a true geological wonder.

02:56Imagine a massive mountain mass stretching from North California to British Columbia,

03:01crossing Oregon in its heart.

03:03Just in this state, it extends over 420 km long and up to 150 km wide,

03:09covering nearly 44,000 km²,

03:12an area exceeding that of the nine smallest American states.

03:16What makes this chain even more impressive is that the part in Oregon

03:21was essentially shaped by volcanoes

03:24and contains at least one reservoir of prisoner water, volcanic rocks.

03:28It owes its existence to the subduction zone of Cascadia,

03:32where the tectonic plate Juan de Fuca,

03:34a fragment of terrestrial crust located under the Pacific Ocean,

03:38gradually sinks under North America.

03:41As it plunges, this plate undergoes extreme temperatures and pressures

03:45that expel the water contained in the oceanic rock.

03:48This phenomenon lowers the melting point of the terrestrial mantle,

03:51thus favoring the formation of magma.

03:53It then rises and feeds the volcanoes of the Cascades.

03:57This process takes place in the belt of fire,

03:59a vast volcanic network surrounding the Pacific,

04:02and illustrates the permanent dynamics of this gigantic geological system.

04:06The Cascades of Oregon are divided into two distinct groups.

04:09The Western Cascades and the High Cascades,

04:12which have very different characteristics.

04:15The Western Cascades, the oldest part,

04:18were formed about 45 million years ago.

04:22They are distinguished by a steep relief,

04:24deeply dug by the streams,

04:27some canyons reaching up to 1,100 meters deep.

04:31Once the seat of an intense volcanic activity,

04:34this region has since been shaped by erosion,

04:37which has gradually remodeled the landscape.

04:40Conversely, the High Cascades are much more recent

04:43and much less eroded.

04:45About 8 million years ago,

04:47the volcanic activity moved,

04:49causing new eruptions that filled old canyons

04:52and softened the relief.

04:54The continuous accumulation of lava

04:56prevented the rivers from digging valleys as deep

04:59as in the Western Cascades,

05:01giving this area a more homogeneous appearance.

05:03Thus, when comparing these two regions,

05:06one appears fractured and chaotic,

05:08while the other seems more uniform

05:10and edified by successive eruptions.

05:12It is in the High Cascades that some of the most

05:15emblematic volcanoes in Oregon are located,

05:17including Mount Hood, Mount Jefferson,

05:19the Three Sisters and Crater Lake.

05:22The latter is from the collapse of Mount Mazama

05:24after a gigantic eruption.

05:26Unlike the small volcanoes,

05:28which briefly emerge and spit a little lava

05:31before disappearing in a few years,

05:33these vast volcanic centers have been active

05:35for millennia.

05:37And because of their size,

05:39they house magmatic systems

05:41of great complexity.

05:43They produce a wide variety of magma,

05:45ranging from basalt, a fluid and fast lava,

05:48to andesite, dacite and rhyolite,

05:50the latter being responsible

05:52for the most violent eruptions.

05:54Thus, if some volcanoes are content

05:56to let lava flows escape,

05:58others are likely to cause

06:01explosions of devastating magnitude.

06:03Another fascinating aspect of these volcanoes

06:05with exceptional longevity

06:07is that their underground magmatic chambers

06:09retain their heat for an extremely long time.

06:12This is what makes the Cascades

06:14one of the best sites to exploit

06:16geothermal energy.

06:18A huge reserve of heat

06:20rests just below the surface,

06:22waiting to be used.

06:24Not to mention the volcanic water reservoir

06:26of the Cascades,

06:28one of the world's most explosive zones.

06:30Imagine a gigantic arch

06:32in the shape of an iron horse,

06:34encircling the Pacific Ocean

06:36for about 40,000 km.

06:38It is one of the most active regions

06:40of the globe,

06:42where the earth's tectonic plates

06:44constantly move,

06:46colliding and collapsing

06:48one under the other.

06:50This process is the origin

06:52of earthquakes,

06:54earthquakes and earthquakes.

06:56This process is the origin

06:58of earthquakes of unimaginable power,

07:00major volcanic eruptions

07:02and the formation of deep oceanic pits.

07:04The belt of fire

07:06follows the lines of contact

07:08between several plates,

07:10including the Eurasian,

07:12North American,

07:14Juan de Fuca,

07:16Cocos, Caribbean,

07:18Nazca, Antarctic,

07:20Indian, Australian and Philippine plates.

07:22They encircle the vast Pacific plate.

07:24The tectonic plates never remain still.

07:26They move continuously,

07:28colliding or sliding

07:30one under the other

07:32at the level of their borders,

07:34known as faults.

07:36This movement generates a diversity

07:38of spectacular phenomena.

07:40Abyssal pits with volcanoes

07:42and devastating earthquakes.

07:44One of the most impressive examples

07:46of this tectonic activity

07:48is the Marian pit,

07:50located east of Guam.

07:52It is the deepest oceanic pit in the world.

07:54It results from a phenomenon

07:56called subduction,

07:58in which one plate is forced

08:00to plunge under another,

08:02progressively sinking

08:04into the terrestrial mantle.

08:06The Marian pit remains

08:08one of the most enigmatic places

08:10on Earth.

08:12From a dizzying depth,

08:14it is subjected to crushing pressure

08:16and total darkness,

08:18which has long been believed

08:20In 2005, researchers

08:22have highlighted the existence

08:24of tiny unicellular organisms

08:26in the Challenger Deep,

08:28the deepest point of the Marian pit.

08:30They have also observed

08:32strange sea cucumbers

08:34as well as rock formations

08:36with unexpected shades.

08:38In addition, the pit houses

08:40hydrothermal chimneys,

08:42a real hot underwater source

08:44where water,

08:46despite extreme temperatures

08:48can be found.

08:50The Marian pit is also

08:52at the origin of 90%

08:54of the world's earthquakes.

08:56Some of the most devastating

08:58earthquakes in history

09:00took place there,

09:02notably the Valdivia earthquake

09:04in Chile in 1960,

09:06which holds the record

09:08of the most powerful ever recorded

09:10with a magnitude of 9.5

09:12on the Richter scale.

09:14But seismic activity

09:16is also at the origin

09:18of 75% of the world's volcanoes.

09:20Some of the most striking

09:22eruptions in history

09:24took birth there,

09:26like the terrible explosion

09:28of the Tambora in Indonesia.

09:30In short, the fire belt

09:32is among the most hostile

09:34regions of the globe.

09:36However, it remains

09:38an irresistible source

09:40of fascination.

09:42Who knows what major discoveries

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