Of the two types of supervolcanoes, only one -- massive eruptions,

Question

Of the two types of supervolcanoes, only one -- massive eruptions, which eject at least 1,000 km3 of pyroclastic material -- actually fits the popular conception of a volcano. Unlike lesser volcanoes, massive eruptions do not form mountains. Instead, the land collapses into the magma chamber below, forming circular depressions called calderas, some of which are more than 25 kilometers in diameter. These calderas can last for millions of years after the volcanic activity has subsided. Probably the best known of these eruptions is the one that occurred at Lake Toba in Indonesia about 75,000 years ago. This eruption led to a volcanic winter and killed about 60% of the human population.

The other type of supervolcano, a large igneous province (LIP), forms in oceans, on continents, and on margins between the two. They are caused by flood basalt eruptions, which are triggered perhaps by rising mantle plume heads encountering the lithosphere and melting, or perhaps by large meteorite impacts. These provinces are the size of continents and are formed over millions of years, a geologically brief time period. Like massive eruptions, LIPs have been linked to extinctions, though less conclusively. LIPs release sulfate gas, which becomes sulfate acid in the atmosphere, absorbing heat and causing the temperature to drop precipitously, perhaps fatally for some life forms. LIPs can also reduce the amount of oxygen in seawater to a dangerously low level.   1 
According to the passage, the eruption of a flood basalt plateau could lead to

A) the collapsing of land into a magma chamber
B) a change in the composition of seawater
C) the creation of a mantle plume
D) a volcanic winter
E) the wide dissemination of pyroclastic matter

2 
Question Which of the following can be inferred from the passage?

A) The eruption at Lake Toba created a caldera.
B) Most people would not think of massive eruptors as volcanoes.
C) The force of a meteorite hitting the Earth may be responsible for mantle plumes rising to the lithosphere.
D) LIPs have been linked to fewer extinction events than have massive eruptions.
E) Massive eruptors do not release sulfate gases.

3 
The primary purpose of the passage is to:

point out the differences between two geological events
 discuss the origins of a class of natural occurrences
 examine a controversial scientific viewpoint
 provide a brief chronological outline of a series of cataclysmic events
 give an overview of two related phenomena

4 
Each of the following is described as characteristic of some volcanoes EXCEPT

A) the creation of mountains
B) formations that exist for millions of years after a volcano has been active
C) an overheating of the atmosphere
D) very large oceanic provinces
E) eruptions that have been fatal to humans

5 
According to the passage, which of the following would be true of a supervolcano that ejects 800 cubic kilometers of pyroclastic material?

A) It would be classified as a large igneous province.
B) It would create a mountain.
C) It would be classified as a lesser volcano.
D) It would form on the margin between an ocean and a continent.
E) It would cause a flood basalt eruption

HG0815 · Answer

These are my reasoning

Ques 1- According to the passage, the eruption of a flood basalt plateau could lead to

A) the collapsing of land into a magma chamber
 -> incorrect
 This is cause of 'massive eruption'
B) a change in the composition of seawater
 -> correct
 a flood basalt plateau connected to LIP(Large igneous province)
 2nd paragraph explaine about LIP.
 Last sentence of 2nd paragraph explained that 'LIP can also reduce the amount of oxygen in seawater to a dangerously low level' 
C) the creation of a mantle plume
 -> incorrect
 This is not result of LIP, but cause of LIP.
 Also, there is a word 'perhaps', so we also cannot assure that mantle plume is absolute cause of LIP 
D) a volcanic winter
 -> incorrect.
 This is about 'massive eruption'
E) the wide dissemination of pyroclastic matter
 -> incorrect
 This is about result of 'massive eruption'

Ques 2- Question Which of the following can be inferred from the passage?

A) The eruption at Lake Toba created a caldera.
 -> correct. This is about contents of 1st paragraph
B) Most people would not think of massive eruptors as volcanoes.
 -> incorrect. It is possible or not.
C) The force of a meteorite hitting the Earth may be responsible for mantle plumes rising to the lithosphere.
 -> Both are cause of 'massive eruption'
D) LIPs have been linked to fewer extinction events than have massive eruptions.
 -> Not mentioned. We cannot know about this.
E) Massive eruptors do not release sulfate gases.
 -> Not mentioned. We cannot know about this.

Ques3-The primary purpose of the passage is to:

point out the differences between two geological events
 -> incorrect.
 At 2nd paragraph, we can see the sentence 'Like massive eruption, ~'
 : It means that the purpose of passage is not point out difference
 discuss the origins of a class of natural occurrences
 -> Not mentioned about the origins.
 examine a controversial scientific viewpoint
 -> incorrect. This passage just explains about phenomenons. There is no viewpoint.
 provide a brief chronological outline of a series of cataclysmic events
 -> incorrect. There is no chronological ouline.
 give an overview of two related phenomena
 -> correct. This is only left thing.

Ques 4- Each of the following is described as characteristic of some volcanoes EXCEPT

A) the creation of mountains
 -> 2nd sentence of 1st paragraph said 'Unlike lesser volcanoes, massive eruption do not form mountains'
 It means that lesser volcano forms mountains. 
 So A is no problem
B) formations that exist for millions of years after a volcano has been active
 -> 4th sentance of 1st paragraph said 'These calderas can last for millions of years after the volcanic activity has subsided'
 So B is no problem
C) an overheating of the atmosphere
 -> Except!! 
 No overheating!!
D) very large oceanic provinces
 -> LIP forms in oceans ,and is size of continents.
 So D is no problem
E) eruptions that have been fatal to humans
 -> 'Massive eruptions' killed about 60% of the human population.
 So E is no problem

bruhnah · Answer

I'm afraid I don't agree with this. The answer might be correct, but I cannot empathize with the argument here.

First: If we are to rely on precise extracts, what more than the very beginning of the text! " Of the two  types of supervolcanoes,  only one  ... actually fits". I even consider this more determining than a phrase mid/paragraph.

Second: Precisely your quoted part of the text seems to further the comparisons: "Like massive eruptions, LIPs have been linked to extinctions,  though less conclusively .

I don't know about you guys, but I feel this question in particular is not up to par with something built by GMAC.

Looking forward to debate it further!

Masterscorp · Answer

I also picked A and can't really understand yet why E is the better option.

It is true that the passage isn't exclusively pointing out differences between the two types of volcanoes but this is the main focus imo.

To me, an overview is a bit more of a wholesome description and we actually do find quite a few facts about the two types of volcanoes. Maybe that is the explanation for the correct answer.

What do you think?

kabirchaudhry92 · Answer

****************************************************************************************************************************************************************

Hello,

I have a doubt in 4th question

The stimulus says " LIPs release sulfate gas, which becomes sulfate acid in the atmosphere, absorbing heat and causing the temperature to drop precipitously "

Isn't this supposed to be a characteristic ?

globaldesi · Answer

one more question for the same passage
According to the passage, which of the following would be true of a supervolcano that ejects 800 cubic kilometers of pyroclastic material?

It would be classified as a large igneous province.
 It would create a mountain.
 It would be classified as a lesser volcano.
 It would form on the margin between an ocean and a continent.
 It would cause a flood basalt eruption

KaranB1 · Answer

IMO- C

B is extreme. Instead if it were worded as "It  may  create a mountain", it could be a correct answer.

globaldesi · Answer

one more question for the same passage
According to the passage, which of the following would be true of a supervolcano that ejects 800 cubic kilometers of pyroclastic material?

It would be classified as a large igneous province.
 It would create a mountain.
 It would be classified as a lesser volcano.
 It would form on the margin between an ocean and a continent.
 It would cause a flood basalt eruption

Answer to the question
When a Specific question includes a statistic, the question is doing you a favor by pointing you to something that should stand out in the passage. Numbers, capitalized proper nouns, italicized text...these things are very easy to find if you need to go find them. So here, with the question asking about 800 cubic kilometers, you should scan for numbers in the text. All the numbers are in the first paragraph, and the first number cited is in the units of cubic kilometers. The correct answer hinges on that definition.

You're told that "Of the two types of supervolcanoes, only one -- massive eruptions, which eject at least 1,000 km3 of pyroclastic material..." This sentence defines that there are two types of supervolcanoes, and then tells you that one of them is for eruptions of over 1,000 cubic kilometers. Since the supervolcano in question is less than that, at 800 cubic kilometers, you know that it's "the other" type.

That type is defined in the second paragraph: "The other type of supervolcano, a large igneous province (LIP)..." This means that A must be true - the 800 km3 supervolcano must then be a large igneous province.

Among the other answer choices, choices B and C are incorrect for similar reasons: this less-than-1,000-km3 volcano isn't defined as a "lesser volcano." You're told that it's a supervolcano, and then that the larger (> 1,000 km3) supervolcanoes are "unlike lesser volcanoes" but there is no direct tie between a < 1,000 km3 supervolcano and a "lesser volcano."

Choice D includes one of there places that a LIP could form, so that is not necessarily true of this particular LIP. And choice E mistakes the cause and effect: LIPs are caused by flood basalt eruptions, but choice E says that this LIP would cause such an eruption.

KeyurJoshi · Answer

Hey I picked A too but I think the OA is quite correct (A) point out the differences between two geological events = Since supervolcanoes are ONE geological event and then it is classified into two types in the passage, We are left with choice (E) i.e. give an overview of two related phenomena

sssanskaar · Answer

Dear experts/  Sajjad1994  , please confirm and change the OA of Qn#5 to C. I don't think that option A should be the correct answer. Thanks.

Sajjad1994 · Answer

Hi sssanskaar

According to the Veritas the OA of the question is indeed A and the difficulty level is 750-800. Below is the official explanation.

Official Explanation

5. According to the passage, which of the following would be true of a supervolcano that ejects 800 cubic kilometers of pyroclastic material?

Difficulty Level:   750

Explanation

When a Specific question includes a statistic, the question is doing you a favor by pointing you to something that should stand out in the passage. Numbers, capitalized proper nouns, italicized text...these things are very easy to find if you need to go find them. So here, with the question asking about 800 cubic kilometers, you should scan for numbers in the text. All the numbers are in the first paragraph, and the first number cited is in the units of cubic kilometers. The correct answer hinges on that definition.

You're told that  "Of the two types of supervolcanoes, only one -- massive eruptions, which eject at least 1,000 km3 of pyroclastic material..."  This sentence defines that there are two types of supervolcanoes, and then tells you that one of them is for eruptions of over 1,000 cubic kilometers. Since the supervolcano in question is less than that, at 800 cubic kilometers, you know that it's  "the other"  type.

That type is defined in the second paragraph:  "The other type of supervolcano, a large igneous province (LIP)..."  This means that A must be true - the 800 km3 supervolcano must then be a large igneous province.

Among the other answer choices, choices B and C are incorrect for similar reasons: this less-than-1,000-km3 volcano isn't defined as a  "lesser volcano."  You're told that it's a supervolcano, and then that the larger (> 1,000 km3) supervolcanoes are  "unlike lesser volcanoes"  but there is no direct tie between a < 1,000 km3 supervolcano and a "lesser volcano."

Choice D  includes one of there places that a LIP could form, so that is not necessarily true of this particular LIP. And choice E mistakes the cause and effect: LIPs are caused by flood basalt eruptions, but choice E says that this LIP would cause such an eruption.

Answer: A

sssanskaar · Answer

Thank you Sajjad1994 ! There is a lot to learn from this question for me. Upon first glance, I made the mistake of assuming the link between <1000 km3 supervolcano and a "lesser volcano". But now I can see that the key to solving this question was to focus on this particular set of words: Of the two types of supervolcanoes. Definitely 750 level stuff. Learning from this question and making a hard note of it.

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Of the two types of supervolcanoes, only one -- massive eruptions,

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Of the two types of supervolcanoes, only one -- massive eruptions,

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