Thursday, November 24, 2011

Three volcano questions, please help I've been working on this project for 5 hours now.?

lava with high amounts of granite usually forms


a- explosive, gaseous volcanoes


b- non-explosive, quiet lava flows


c- shield volcanoes


d- magma that is high tn basalt





In the late 1800's , an island volcano in Indonesia, Krakatoa, erupted explosiveley. what kind of lava did the volcano erupt?


a- basaltic


b- granitic


c- silicic


d- magmic





If a volcano does not form at a hot spot, it must form at a


a- laccolith


b- crater


c- plate boundary


d- batholith|||For the first question, granite doesn't erupt, it's an intrusive/plutonic rock type. Assuming what's really meant is rhyolite, granite's extrusive/volcanic counterpart, the answer is A, explosive, gaseous volcanoes. Shield volcanoes, such as the one I live on (Mauna Loa) are not made of granite/rhyolite and basalt is a type of magma not something a magma can be high in so C and D are out. B is not the correct answer because granite/rhyolite is a silicic magma and they don't erupt quietly.





For question two, the answer is C, silicic because silicic magma (such as rhyolite) erupts explosively. Basaltic lava erupts effusively, granite doesn't erupt as I already mentioned, and magmic isn't a type I've ever heard of.





For question three, the answer is C, a plate boundary. Laccoliths and batholiths are both types of intrusive magma bodies and a crater is a depression feature (sometimes associated with volcanic activity, but not always), so those are not places volcanoes form.|||1: a





2: a ?





3: c|||i dont know the first two without contacting the very back of my mind, but the last one is "c". good luck on your project.|||c c, and a. just studied that stuff.|||I can assure you that the first answer is most definitely A. Granitic magma has a high viscosity (due to it's lower temperature and higher silica content) that traps a lot of gas, when this gas reaches the low pressures of the surface it explodes out making for violent and destructive eruptions.





Answer two I can't tell you with 100% certainty, but it is safe to assume that Krakatoa erupted felsic (granitic) magma. Basaltic eruptions are usually not violent and are not associated with pyroclastic flows - Krakatoa's 1883 eruption is the most violent eruption in modern times and ejected huge volumes of gas and ash these are not typical of a basaltic volcano. Magmic is not a word so you can discount that answer. The answer is either B or C -- as granite is a silicic rock (silica rich rock). If I had to choose I would go with C, just because I do not know exactly what kind of magma Krakatoa erupted, but I'm sure it had a high silica content.





As for the last question... The answer is C.





edit: The answer after me is 100% correct, granite is an intrusive rock, and is never erupted (something I stupidly failed to remember) - so definately go with C for question two. In question one, what it could mean is magma that has melted and mixed with large amounts of granite, not that the lava itself is going to form granite -- otherwise, as the answer after mine says, it should say rhyolite which is the extrusive equivalent of granite.|||number three is most def c.......





not a. not a at all

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