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A4/ Observation de lames minces de 4 roches magmatiques / microscope
©TP roches :
pour apprendre à reconnaître les minéraux et roches : manuel p.398-399
tableau récapitulatif Dijon (doc) : http://svt.ac-dijon.fr/dyn/article.php3?id_article=261
collection de roches : http://geoeco.ifrance.com/g%E9ologie/collec.html
collection de lames minces : http://www2.ac-lyon.fr/enseigne/biologie/photossql/photos.php?TopicID=Lames
clef de détermination Tlse (html) : http://pedagogie.ac-toulouse.fr/svt/serveur/lycee/segui/mineralogie/fiche.htm
clef de détermination Oehmichen (pdf) : http://www.google.fr/url?sa=t&rct=j&q=identification+min%C3%A9raux+microscope&source=web&cd=1&ved=0CCUQFjAA&url=http%3A%2F%2Fwww.lyc-oehmichen.ac-reims.fr%2Fcontenu%2Fdiscipline%2Fsvt%2F01_Pour_Observation2%2FIdentification_des_mineraux.pdf&ei=ih9kUP_rKorM0AWbjoCoCg&usg=AFQjCNHuA10fkEWvcu9xBWoHpXz13EnO9Q
clef de détermination Grbl : http://www.ac-grenoble.fr/svt/SITE/prof/outiensei.htm
atlas rocks & minerals / Ratajeski : http://www.geolab.unc.edu/Petunia/IgMetAtlas/mainmenu.html
atlas minerals / Siddall, London : http://www.ucl.ac.uk/~ucfbrxs/PLM/PLMhome.html
atlas de roches et minéraux webminéral BRGM :
atlas de minéraux : http://www.brocku.ca/earthsciences/people/gfinn/minerals/database.htm
atlas de lames minces Minéraux et roches / Aubry, Caen : http://www.discip.crdp.ac-caen.fr/svt/cgaulsvt/travaux/Micropol/index.html
article de minéralogie au microscope polarisant : http://www.svt-monde.org/spip.php?article26
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Earth cracking up under Indian Ocean
- 26 September 2012 by Colin Barras
- Magazine issue 2884. Subscribe and save
YOU may not have felt it, but the whole world shuddered on 11 April, as Earth's crust began the difficult process of breaking a tectonic plate. Whentwo huge earthquakes ripped through the floor of the Indian Ocean, they triggered large aftershocks on faults the world over, and provided the best evidence yet that the vast Indo-Australian plate is being torn in two.
Geologists have spent five months puzzling over the twin quakes - of magnitude 8.6 and 8.2 - which took place off the coast of North Sumatra. Events that large normally occur at the boundary between tectonic plates, where one chunk of Earth's crust slides beneath another, but these were more than 100 kilometres from such a subduction zone. What's more, both involved rocks grinding past each other sideways with very little vertical movement - what geologists call strike-slip earthquakes. Yet strike-slip quakes this large had never been reported before.
Matthias Delescluse at the École Normale Supérieure in Paris, France, and his colleagues have an explanation. They analysed quakes in the area since December 2004, when a magnitude-9.1 quake in a subduction zone near Sumatra triggered a devastating tsunami. They found earthquakes during this period were nearly 10 times more frequent compared with the previous eight years. What's more, 26 of the quakes that happened between December 2004 and April 2011 were similar to the 11 April quakes in that they involved rocks being pushed and pulled in the same directions.
Taken together, the events suggest that the Indo-Australian plate is breaking up along a new plate boundary, say the researchers, and that may account for both the location and the size of April's quakes (Nature, DOI: 10.1038/nature11520). Although both are currently on the same plate, Australia is moving faster than India. This is causing a broad area in the centre of the Indo-Australian plate to buckle. As a result, the plate may be splitting (see map).
John McCloskey at the University of Ulster in Coleraine, UK, is not yet convinced, saying the evidence from the April events is still too weak to support such a bold claim. But Lingsen Meng at the University of California, Berkeley, who studied the rupture pattern of the larger 11 April quake, is more confident. "I think it's a fair argument that the 11 April earthquakes may mark the birth of a plate boundary," he says. Things should become clearer as more earthquakes shake the region.
If they are anything like the 11 April events, the rest of the world may shake too. In another new study, Fred Pollitz at the US Geological Survey in Menlo Park, California, and his colleagues found that the global rate of quakes with a magnitude of 5.5 or greater increased almost fivefold in the six days after 11 April - something that has never been seen before, even after very large earthquakes (Nature, DOI: 10.1038/nature11504).
"This was the most powerful event [ever recorded] in terms of putting stress on other fault zones around the world," Pollitz says.
http://www.newscientist.com/article/mg21528843.500-earth-cracking-up-under-indian-ocean.html
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Ocean Acidification Can Mess with a Fish's Mind
In more acidic waters clown fish wander too far from safety, sea snails fail to avoid prey
http://www.scientificamerican.com/article.cfm?id=ocean-acidification-can-m
Monterey, Calif.—Mental problems at sea? Fish and mollusks could begin to have them—thanks to rising CO2 levels. Some of the resulting behaviors are odd, some compromising, and they reveal just how fundamentally carbon emissions are affecting our increasingly fragile Earth.
As humans emit more carbon dioxide into the atmosphere, more of the gas is absorbed by the oceans, gradually making the water more acidic. Numerous studies in recent years have documented how lower pH (higher acidity) can make it harder for shellfish and tiny organisms to form shells or internal skeletons and to reproduce. The acidity often forces the organisms to expend extra energy to counteract ill effects on their metabolisms as well. But now scientists are finding that lower pH can also mess with ocean animals' minds.
Small clown fish (yes, Nemo), for example, normally stay extremely close to the coral in which they spend their entire lives. But as the water becomes increasingly acidic—as in various recent experiments—they tend to wander farther and farther from home. This uncharacteristic "boldness" is not necessarily a good trait because the farther they swim, the more likely they are to get eaten by predators. Greater acidity also "impairs their ability to discriminate between the smell of kin and not, and of predators and not," according Philip Munday, a professor and research fellow at the Coral Reef Studies center at James Cook University in Australia, who conducted the experiments and presented results at a symposium here this week called The Ocean in a High-CO2 World.
Other species exhibit equally unusual behaviors. A snail known as Chilean abalone, which adheres to rocks along wave-swept shores, quickly rights and reattaches itself when it is dislodged, an important skill for avoiding predators. But when CO2 levels were raised by about 50 percent, some snails were slow to right themselves and others did not do so at all. "Their decision-making is delayed," said Patricio Manriquez, a researcher at the Southern University of Chile. Some snails took wrong turns in trying to avoid crab predators, and some even turned into the crab's claws instead of away from them.
In experiments done at the Monterey Bay Aquarium Research Institute here, hermit crabs living in highly acidic conditions did not show the increased boldness of Munday's clown fish, but they took far longer to withdraw into their shells than normal when they came under attack from a potential predator (in this case, a toy octopus).
Researchers are not sure what is causing the peculiar behaviors but Munday suspects that elevated CO2 levels interfere with a neurotransmitter called GABA, which plays a key role in modulating activity in the brain and nervous system of virtually all animals, including humans. In one experiment, Munday exposed reef fish to high CO2, which interfered with their sense of smell. He then administered a compound that helps to facilitate activity by receptors that sit on nerve cells and direct the cells' responses to GABA, and the abnormality was reversed. Because GABA is so ubiquitous, Munday fears that ocean acidification could cause sensory and behavioral problems for many sea creatures if global CO2 levels continue to rise.
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A1/ Ensemencement de cellules différentes sur différents milieux / culture in vitro
Présentation des cellules (Euglena normales ou mutées) et milieux de culture (organique et/ou minéral)
Conseils pour travailler en conditions stériles
Euglenoid party : http://www.youtube.com/watch?gl=FR&hl=fr&v=0rNI8Bos_BQ&feature=related
photographies d'euglènes :
http://www.microscopies.com/DOSSIERS/Galerie/PLANCHE-4/IMAGES/Euglene-F-Quinquet.jpg ;
http://37.img.v4.skyrock.com/37b/siocnarf/pics/599729223_small.jpg ;
http://svt.ac-rouen.fr/biologie/cidre/fermentation/image/multiplication.jpg ;
http://xxi.ac-reims.fr/svt-reims/page-a/activite2-2.htm
schémas à télécharger au format doc :http://svt.ac-dijon.fr/schemassvt/article.php3?id_article=945
http://svt.ac-dijon.fr/schemassvt/article.php3?id_article=40
http://www.infovisual.info/02/001_fr.htmlinfos sur les euglènes :
http://www.ac-reims.fr/datice/svt/docpedagacad/lycee/sciencvie/cellule/algues/activite_3.htm ;
http://www.snv.jussieu.fr/vie/dossiers/culturedecellules/euglenes.htm ;
http://pedagogie.ac-toulouse.fr/svt/serveur/lycee/sanhard/euglene.html ;
http://pedagogie.ac-amiens.fr/svt/info/logiciels/Mesurim2/exemples/algues/algues.htm
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A4/ Recherche de traces tectoniques dans les montagnes / www
étude structures géologiques / photos = témoin collision : http://www.discip.crdp.ac-caen.fr/svt/cgaulsvt/travaux/collisionweb/index.htm
pli, faille, nappes => collision
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