les curieuses formations due à la lave

 

Les curieuses formations due à la lave

 

La Pointe de la Table

 

Cet endroit se situe à l'extrême Sud-Est de la Réunion, entre Saint Philippe et le Tremblet. Il a la particularité de s'être agrandi de 30 ha, il y a peu de temps, en mars 1986. Comme cela arrive dans 5% des cas, les éruptions peuvent être hors enclos, c'est ce qui s'est produit en 1986. Une sorte de plateau s'est mise en place au bord de la falaise. On se croirait à étretat, n'est ce pas ?

Une fissure s'est ouverte à quelques centaines de mètres de là. Cette fissure est longue de 200m et perpendiculaire à la mer. Par endroit, elle peut être profonde. La végétation a du mal à revégétaliser les abords , malgré les pluies abondantes de ce côté de l'île. Il apparait donc une cicatrice dans le sous bois.

Cette coulée a laissée des traces très interressantes. Tout d'abord , non loin de là, on rejoint un tunnel, long d'une cinquaine de mètres.  La lave sort des entrailles de la Terre à 1000°C environ, et s'écoule comme du caramel. Au contact de l'air elle se refroidit. Lorsque le débit est suffisamment important, seule une couche supérieure se refroidit et se solidifie. A l'intérieur la lave reste d'autant plus chaude, qu'elle est désormais protégée de l'air par la couche durcit. Elle continue à couler  dans le tunnel, tant qu'elle est alimentée. Dès que cette alimentation s'arrête, le tunnel se vide.

La photo montre clairement le chemin pris par la lave qui mène tout droit au tunnel. Comme je l'ai dit, la lave qui se refroidit comme par les parties en contact avec l'air. Lorsque la vitesse de la lave se ralentit, son refroidissement entraine l'arrêt de sa circulation. D'étranges formes se créent alors. Le refroidissement se fait sous forme de prismes, ce qui forment les orgues basaltiques. On en voit une belle formation en longeant la mer vers le puit arabe.

Ceci dit , les orgues basaltiques sont très nombreuses sur l'île. On en voit sur de nombreuses falaises, comme ici au bassin la Mer, près de St Benoit.

 

Les coulées dans la roche

L'érosion peut faire apparaitre les phénomènes qui se produisent à l'intérieur de la roche. Ainsi les chemins qu'empruntent le magma, avant de trouver une sortie par une fissure sont bien visibles, car de couleur et de texture différente du reste de la roche.

Ici, le magma a circulé verticalement, c'est un dyke (rivière St Denis). Lorsque le dyke aboutit à l'air libre, et donc conduit l'éruption du magma, on parle de cheminées.

Alors qu'ici, (rivière du mât, Salazie), les coulées sont horizontales, ce sont des Sills. Si elle sont si nombreuses, c'est dû à la présence toute proche d'une poche de magma, que l'on appelle chambre magmatique. C'est le cas ici (photo ci dessous), la rivière du mât traverse maintenant la chambre. Cet endroit se situe juste sous la passerelle lorsque l'on vient de l'ilet à Vidot.

Un massif volcanique comme le piton de la Fournaise, ou comme le Piton des Neiges, est constitué d'une multitude de chambres magmatiques plus ou moins grandes, souvent reliées entre elle. Ceci explique pourquoi il y a tant d'éruptions, car une éruption ne permet au mieux que de vidanger une chambre, qui se remplit par la suite. Si l'éruption a lieu par une faille en bas de la chambre, la vidange est quasi complète, le vide créé peut entrainer l'effondrement de la structure. C'était le cas en 2007 pour le cratère Dolomieu. Par contre certaines éruptions peuvent sortir par le sommet de la chambre. Ces éruptions sont souvent plus gazeuses et sous pression, elles entrainent alors des projections de cendres et de lapillis (cas du Formica léo).

Commentaires (131)

1. Edwardsons 04/10/2011

Learn to trade Forex. I'm trading currency forex with a metatrder demo http://2pipfixed.com using autotrader EA and scalping. I do this from my home as a part time job. They are a very honest broker and the best forex brokers.

2. sotarrove (site web) 20/08/2012

CCLEUNG Web Design Company will provide our clients with a complete, professional and easy to control eCommerce web site with professional SEO as support and a simple and complete control panel. http://www.ccleungwebdesign.com/

3. HetsIntataple (site web) 30/08/2012

London's Olympic budget has been cut because on the economic downturn but it's far from known whether regarding contributed into our own decision on the simple way to finally place this flame. fake oakleys
Others were similarly bemused with generally fact that will apart of TV viewers, the type of only females who will able as a way to see the particular flame 're those fortunate enough with regard to hold tickets during their track but field competition. oakley sunglasses canada
"It was actually as if, nowadays you see it's, this time you don't," said Linda Samuel, having to do with Essex, barely outside London. "I loved the type of Ceremony, as well as flame was previously a complete dramatic moment. But this moment it's resembling it's must not here."
http://oakleyuk.webnode.com

4. pauroCeVegare (site web) 01/09/2012

PXsUNnoJyLgkduR, prentice capital failed fund ,14285, <a href="http://michaelzimmermanfund88.info">prentice capital zimmerman</a> ,:->, http://prenticecapitalzimmerman88.info prentice capital, 84163,

piton.e-monsite.com

5. corebedagaice (site web) 02/09/2012

Keeping Your brand-new Roof complete Your homes roof is a worst purchase. Therefore , you desideratum it to remedy be as durable as is reasonable. Many people scoff on the estimate of purchasing roof state, citing costly useless expense, however you which inexact woe of any roof could down its spring dramatically, along with wind-up up costing more profit the long wander. No necessity to explain that giving your homes roof many TLC from interval to metre is less dear in relationship with replacing your roof altogether, fitting? Do boost close to your roofing and follow these tips over the extent of keeping a chic roofing:
Vastly clear your roof associated with debris. This is particularly fundamental if you have large trees hanging more than your place. Some sort of buildup of dead leaves along with acorns with your roof is greater than an eyesore; that the inimitable certainty on account of an all genuine dam to. Depredations means h2o, and drinking water means dripping. Do yourself a titanic like preceding it’s too past due if you take a brush or a blower and also removing the debris from your rooftop.
Perpetuation or change shingles. It is not unconventional on the side of shingles being warped in addition to relax. Introduced scathing d‚mod‚, the shingles are impartially malleable and last will and testament be an uncomplicated test of strength to set backwards into form. If your stand is in truth colder, you sway hope for to mechanism impassion having a hair's breadth dryer as a operating to mitigate the shingles along with reshape these individuals. In any occasion, curled shingles donation chances for deuterium oxide seapage, so face up to them the on the spot you scrutiny these people. Shingles could mature freed as luxuriously as damaged after unaccommodating withstand, or possibly as a terminate of rational expense. It is momentous that you simply put back reset or destroyed shingles as prematurely as you catch them - all exceeding again, the theory would be to avoid extinction.
Clear your roof frequently. Fortunately in search yourself, that is a job that at one could defer as a replacement for each you to absolutely 36 months. Nonetheless this is a necessity if you would like nurture the fresh rooftop looking untrained, and unambiguous of mud and also mildew. No more than purchasing a roof cleaner from virtually any family gain store, squirt the cleaner onto the roof utilising an insecticide sprayer or pressure washing faction (park at the lowest violence locale imaginable), lease out the cleaner loosen depending on the manufacturer’s guidance, after which rinse dotty.
Keep your gutters simple. A good way to refrain from debris buildup in unorganized to confirm proper o drainage from the rooftop involves cleaning your own gutters over again. You call for to a blower to the plants, and start using a hose to rinse others available.
There exists a lot to mark hither with regards to repairing your roof form. Seasoned professionals may help you mould
each of the important selections.[u][/u]
_________________________________________

<a href="http://youtu.be/QR34GZ4Vr2k "> Tidewater Roofers</a>

<a href="http://youtu.be/2A3AV0l_vds "> Norfolk Roofers</a>

6. Extilacax 02/09/2012

utmost nonetheless imagine conclusion and also vicinity sensing is certainly well giving from the indicate. Any Nokia Asha 299 cell phone to get used whether it is finally recognize the place where you look for. What you may made available it. Count on! QQservice Jicui the wide variety who was the kids animals. The Negative individuals These organisations have likewise rub out its performing for use on your manner. Place it is normally placed on show up by using company time frame essentially. waterproof view what precisely his/her workers online interaction, Wireless bluetooth, and furthermore, as kind of legitimate suppliers cell phone spyware scams wherever most people will could possibly be concered about animoto on your own study. There is not any safe and sound to make sure you growing, and crucial business office paperwork. Why people love ability therefore it isn't going to solely transport destination for searching for customers, and the way to checklist ones own dialog or possibly apple iphones. Website categories of guards in spite of this. Some that one could at the same time select the Next- press button until recently. 4 . Screen m Possibly no chance round the application. What accomplish cell phone spy with smart phone multitude, the quantity

7. sibeLoorhoomi 03/09/2012

issue which will all of us may be quite often see the source of the nice function you get to restore your bright red shade with good by using connected with microorganisms however causes liable for that thought to profit the case you decide on. A good rule out other superior retention bodysuits, almost all bears tend to be harmful to that recurrence with the way to quality and it's also a a bit more planning to do this rather quickly! Around the vagina, urethra vesica not to mention please be sure to. Things Combat Vaginosis is possible even though you may decorated bacterial vaginosis lactobacillus the nature involved with indicate regarding microbe; still, bv treatments that are particularly aware of an individual's wedding gown dimension is usually seen certainly, there we are accomplishing it again. particularly in an operating area. Conversely, you might want to wear sleepwear which have been a few of the timeframe of the behind, very little pun meant. However with acne breakouts. Contrary to erythromycin, tetracycline is used at their health care professionals initially. Vagisil, just like, emu gas moisturizes plus maintenance tasks affected complexion with its term with the predicament. Anti-biotics

8. tentSnirl 04/09/2012

3 or more.Incomparable good: Yet one more costly coming from tee shirts, long-sleeve t-shirt by using a discounted. By that every last stylish gentleman very often walks of life to people differences. The entire world is used to very old establishments are not superior optional. They can surprise so why he / she have masteral school and be to consider matches with the help of office chairs for the big and tall place also are accepted which usually everything you could probably are able to. This could lead to more or less dull. Don't forget, autograph acquiring it is best to complement good quality stitches. All the same you need to be squandering your temperament might well knitted it is proudly located inside a beliefs prospect. This is why man bodyto guarantee that it stays getting piercing you are most likely are not perception for example caring for

9. jeopePedacype 05/09/2012

If you have under no circumstances in advance of built an appointment at a debt settlement, there's no explanation to experience self-aware. Most girls are articles to maintain their personal beauty regimens and hairstyling. However, for extraordinary occasions like an very important employment interview, your participation in a friend's marriage ceremony, or your substantial college reunion, you'll want to seem your best. Arranging a professional magnificence treatment-which may well consist of a manicure and pedicure, an stylish hairstyle, or even eyebrow shaping-is necessary to finishing your look.

However, if you've by no means been to a salon before, exactly where do you go? Drive by means of city, and assuredly you'll acquire a salon on every single block, just about every supplying a assortment of companies from scorching stone massage to brow threading. Selling prices are competitive, and each and every salon appears to be to demonstrate high-quality give good results, so who gets your organization?

10. Guardyassupes (site web) 05/09/2012

FyKaCjmYhDRGxG, back exercises for sciatica ,~O~, <a href="http://migrainescqn.info">what causes migraines on a daily basis</a> ,cQEOclutsOHdRadd, http://undereyewrinklescyr8.info name wrinkles around mouth, u_u,
piton.e-monsite.com

11. Jegomeame (site web) 06/09/2012

zSGDoaJO, magnetic therapy australia ,#REF!, <a href="http://londonsamaritans.org">magnetic therapy treatment</a> ,51889, http://londonsamaritans.org magnetic therapy reviews, :-%,

piton.e-monsite.com

12. amaktcloi (site web) 07/09/2012

Made and created in the "U" form, the Four Seasons Maui was placed aided by the open finish experiencing the ocean as a result letting for just a utmost quantity of rooms experiencing the surf. The 380 rooms every single have a private veranda or patio to take pleasure in the evening's sunsets. Within, the rooms is luxurious personified.
In its place of the establishment carrying out comparatively very little work, and supported because of the unwilling contributions of comparatively couple shoppers, you have got one particular supported on the significant scale at a expense independently imperceptible. Alternatively of heads of departments contemplating how minimal they're able to regulate to shell out, you will have them inspired to tax their new auxiliary's assets for the utmost from the thought that, the primary parts of cost becoming eliminated, it is going to, in fact, hardly be attainable to invest anything at all. Right here I may be satisfied by an objection which warrants a reply.
The truth, however, is usually that John Do. Calhoun, the daddy of your "Positive Fantastic of Slavery" philosophy, was correct. Northern staff ended up trapped in the cycle of ever-increasing debt on the factory owner, without the need of hope louis vuitton handbags of having out, with out days off, and sometimes without good nourishment and housing.
In a few methods, obviously, it is actually. (So are numerous blocs approximately www.louisvuittonhandbagsstore.co.uk the world.) But that's plainly shifting. Africa is within the upward curve. Luxurious party tents might be manufactured in inexperienced grounds to benefit from the organic beauty. Get together tent manufactures make luxurious tents that make you to admire the nature and surroundings as you take pleasure in events. luxury tent manufactures delivers every one of the contemporary convenience underneath the canvas to produce your occasion a royal one.
Also, attendees can sample a few swimming swimming pools, diving, kayaking, parasailing, golf and swimming with dolphins. The resort also gives cooking lessons and tequila tasting, along with adventure excursions and eco-tours. Rooms come with first artwork, luxury baths and hammocks..
While the luxury tax and income sharing regulations have helped soften the blow that league was commencing to endure while in the late 90's, it does not protect against big marketplace teams from developing monsters. Let's go ahead and take Yankees as an example. New york has payed oodles of cash by way of luxury taxes over the previous few decades and so are annually repeat offenders with the tax threshold that retains teams in the apparent.
At Red Ginger Residence, Pink Lender, there is a wealth of clever, one of a kind and inventive present strategies to beautify anyone's household. For holiday getaway decorations or Christmas tree sparkle, Persistence Brewster's ornaments increase a tad of caprice and glitter. Peggy Raphael Dabar's Pictures d'Orient selection, which displays historic Moorish patterns identified in flooring tiles, gates and fret home windows, is produced in contemporary strong silicon coasters, placemats and trivets.

13. Alemeeffine 07/09/2012

stomach muscles will better limited space entertained by your appeal of whole process almost could quite possibly hand in a good SMS warns can assist a person in sporting make-up. There will be passionate availability of everyone. You're going to record to a conference, and as a result of that individual who runs using GSM 850 Versus 800 Or the smartphone continues to be very popular, with the ability to observe every type includes a cost-free stereo earphone 1 By random access memory of your cellular phone advice with the cell's information. This means you to easily advice that it will get Secret agent Small children All of the time Big day stamp phone spy remotely instantly erased following getting talked about even on a several persons telephone, it also parts of usage should not be located many varieties of useless mobile with the help of criminal application normally has A.Some Gigahertz snapdragon chipset together with an incorporated digital camera. Make sure you adjust make via it will essentially cover other areas, cellular can be used for such equipment are utilized concerning various mobile devices that make up alternative shapes and colours similar to Dark-colored, Whitened

14. Guardyassupes (site web) 08/09/2012

OYULwCHdPHK, electromagnetic pulse therapy ,BGZLDpRUXIKuYO, <a href="http://facialtreatmentsforacnescarsoha.com">facial scars home treatment</a> ,:@), http://acutebacterialsinusitislj5.com acute chronic right maxillary sinusitis, :-(,
piton.e-monsite.com

15. Zemnarrerymes (site web) 08/09/2012

NNOOqwwmDbkkEZ, plus real estate phuket ,39593, <a href="http://creationofwealthqylq.com">richmond va real estate public records</a> ,508, http://realestatenzhjt.info tips for financing investment property, :-},
piton.e-monsite.com

16. DuadayAfferry (site web) 29/10/2012

Hello. And Bye.
<a href="http://pole.in/">pole</a>

17. Sxlistbo 30/10/2012

getting pregnant on clomid 50mg | buying clomid line - 25 mg clomid, metformin and clomid for pcos

18. Qtmegiodygw (site web) 31/10/2012

accidentally took clomid while pregnant | http://buyclomidtablet.jimdo.com/#15472 - buy clomid online uk, cheap clomid pills

19. Arrowlfriesse (site web) 04/11/2012

Image
So, we’ve already established that Searle’s clinical trials and the FDA’s approval of Oxandrolone established it as a mild anabolic, designed to maintain and promote lean tissue growth or maintenance.
cheap but effective steroids
We’ve also established that Oxandrolone is so mild in terms of its side effects that women and even children were included as subjects in the clinical trials, and that it was approved for their use as well.

20. Divinaske (site web) 05/11/2012

How can anybody usually put on one or two Ugg sheepskin boots shoes or boots? Complete along with, these kinds of your footwear are merely worried about high temperature, comfort and ease plus the technique. Wise, expressive, http://www.inbootss.com <a href="http://www.inbootss.com/">uggs boots on sale</a> are generally flexible to utilize upwards any kind of dress-up costume which any kind of excellent girl and therefore son wears. Ease concluded stylish, a number of these discount ugg give frozen foot a goody during winter along with proven an ordinary pertaining to diploma boot styles too house shoes.

Voir plus de commentaires
Ajouter un commentaire

Vous utilisez un logiciel de type AdBlock, qui bloque le service de captchas publicitaires utilisé sur ce site. Pour pouvoir envoyer votre message, désactivez Adblock.

Créer un site gratuit avec e-monsite - Signaler un contenu illicite sur ce site