Of the Two Types of Supervolcanoes, Only One -- Massive Eruptions GMAT Reading Comprehension

Reading passage question

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.

“Of the two types of supervolcanoes, only one -- massive eruptions, which eject at least 1,000 km3 of pyroclastic material.”- is a GMAT reading comprehension passage with answers. Candidates need a strong knowledge of English GMAT reading comprehension.

This GMAT Reading Comprehension consists of 5 comprehension questions. The GMAT Reading Comprehension questions are designed for the purpose of testing candidates’ abilities in understanding, analysing, and applying information or concepts. Candidates can actively prepare with the help of GMAT Reading Comprehension Practice Questions.

Solution and Explanation

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. 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:

A) point out the differences between two geological events
B) discuss the origins of a class of natural occurrences
C) examine a controversial scientific viewpoint
D) provide a brief chronological outline of a series of cataclysmic events
E) 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

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