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First identified in 1969, komatiites are Earth’s oldest known

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Re: First identified in 1969, komatiites are Earth’s oldest known [#permalink]
(B) it is.

Discovery of "K" - in 1969 => Require hottest LAVA(which can be formed only in high temperatures).
k = 3(Mg than general Lava) and High MG requires High Temperatures.

So "K" was discovered => there existed LAVA rich in MG and HIGH Temp.

1960 - view was molten magma and blah blah.Two scientist checked for the existence of high MG with low temperature and thereby one of the SCI testified that HIGH Temp is req => HIGH MG.

So the Discovery of "k" changed assumptions of many scientists .(Significance of the discovery).
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Re: First identified in 1969, komatiites are Earth’s oldest known [#permalink]
2
Kudos
Information in the passage suggests which of the following concerning the Earth’s mantle 2.5 to 4
billion years ago?
A. It contained magmas that were more significantly affected by the decomposition of minerals than
are current-day magmas.
B. It contained a lower proportion of water that it contains today.
C. Its characteristics were accurately described by both Bowen and Hess.
D. Its temperature was sufficiently high to produce magmas with high magnesium content.
E. Its total magnesium content then was roughly equivalent to its magnesium content today.

Which of the following most accurately states the main point of the passage?
A. Komatiites provide information about rates of volcanic eruption between 2.5 and 4 billion years
ago.
B. Komatiites provide information about how the physical properties of lava in the Earth’s past
compare with those of current-day lava.
C. Komatiites provide evidence that undermines Bowen’s experimental conclusions regarding the
temperatures at which lava exists as a liquid.
D. Komatiites provide evidence that has changed geologists’ ideas about the characteristics of the
Earth’s mantle between 2.5 and 4 billion years ago.
E. Komatiites provide evidence that water in the Earth’s mantle may have reduced the temperature
required for lava to exist as a liquid.
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Re: First identified in 1969, komatiites are Earth’s oldest known [#permalink]
1
Kudos
Time Taken 6:24. All Correct.

Information in the passage suggests which of the following concerning the Earth’s mantle 2.5 to 4 billion years ago?
A. It contained magmas that were more significantly affected by the decomposition of minerals than are current-day magmas.
B. It contained a lower proportion of water that it contains today.
C. Its characteristics were accurately described by both Bowen and Hess.

D. Its temperature was sufficiently high to produce magmas with high magnesium content.

ButBowen showed experimentally that the hightemperatures were indeed necessary. By 1960, it was generally accepted that volcanic rocks with such high levels of magnesium could not exist, and thus the discovery of komatiites changed geologists’ assumptions about the characteristics of the Earth’s mantle around the time of the formation of komatiites,between 2.5 and 4 billion years ago.

E. Its total magnesium content then was roughly equivalent to its magnesium content today.

Which of the following most accurately states the main point of the passage?
A. Komatiites provide information about rates of volcanic eruption between 2.5 and 4 billion years ago.
B. Komatiites provide information about how the physical properties of lava in the Earth’s past compare with those of current-day lava.
C. Komatiites provide evidence that undermines Bowen’s experimental conclusions regarding the temperatures at which lava exists as a liquid.
D. Komatiites provide evidence that has changed geologists’ ideas about the characteristics of the Earth’s mantle between 2.5 and 4 billion years ago.
Thats is pretty much covered in the starting and end of second para.
E. Komatiites provide evidence that water in the Earth’s mantle may have reduced the temperature required for lava to exist as a liquid.
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Re: First identified in 1969, komatiites are Earth’s oldest known [#permalink]
1
Kudos
Interesting passage . Took 7 mins 30 seconds , including 2 mins 30 seconds to read .

-The author describes a certain phenomenon that was first identified in 1969
-The author then discusses the significance of that phenomenon

1. B

2.“By 1960, it was generally accepted that volcanic rocks with such high levels of magnesium could not exist, and thus the discovery of komatiites changed geologists’ assumptions about the characteristics of the Earth’s mantle around the time of the formation of komatiites, between 2.5 and 4 billion years ago."
Since geologists assumed that temperatures weren’t high enough to produce magmas with sufficient magnesium content, the information in the passage changed those assumptions leading to option (D) as the right answer choice.

3.
“By 1960, it was generally accepted that volcanic rocks with such high levels of magnesium could not exist, and thus the discovery of komatiites changed geologists’ assumptions about the characteristics of the Earth’s mantle around the time of the formation of komatiites, between 2.5 and 4 billion years ago."
Option (D) is a clear word justification of the above and is hence correct.
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Re: First identified in 1969, komatiites are Earth’s oldest known [#permalink]
GMATNinja

Hi,

Can you please help me with Q1 of the passage?
Isn't the passage saying that the discovery is surprising and that the temperature this high cannot exist?

Regards
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Re: First identified in 1969, komatiites are Earths oldest known [#permalink]
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Re: First identified in 1969, komatiites are Earths oldest known [#permalink]
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