Determining the authenticity of purported pre-Columbian : GMAT Critical Reasoning (CR)
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# Determining the authenticity of purported pre-Columbian

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Determining the authenticity of purported pre-Columbian [#permalink]

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14 Jul 2008, 07:04
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Determining the authenticity of purported pre-Columbian artifacts is never easy. Carbon-14 dating of these artifacts is often impossible due to contamination by radioactive palladium (which occurs naturally in the soils of Central and South America). However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts. First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding. In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas.

The criteria above would be LEAST useful in judging the authenticity of which of the following?

(A) An ax head of black obsidian, unearthed from a kitchen midden
(B) A pottery bowl with a red ocher design, found in the ruins of a temple
(C) A set of gold ear weights, ornamented with jasper pendants
(D) A black feather cape from a king’s burial vault
(E) A multicolored woven sash found near the gravesite of a slave
[Reveal] Spoiler: OA
If you have any questions
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14 Jul 2008, 07:15
IMO it should be A

because its black and unearthed
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14 Jul 2008, 08:11
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I'm picking C by POE

lordw wrote:
Determining the authenticity of purported pre-Columbian artifacts is never easy. Carbon-14 dating of these artifacts is often impossible due to contamination by radioactive palladium (which occurs naturally in the soils of Central and South America). However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts. First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding (To me this means they must be found in the ground). In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas (This is the second part and makes it seem the artifacts must be found in the ground since they must be exposed to magensium in the soil).

The criteria above would be LEAST useful in judging the authenticity of which of the following?

(A) An ax head of black obsidian, unearthed from a kitchen midden

found in the ground (unearthed), could have gridding

(B) A pottery bowl with a red ocher design, found in the ruins of a temple

found in the ruins of a temple so it's not likely someone discarded this after the temple was ruined, but the temple would have been exposed to the soil, so the pottery would be too

(C) A set of gold ear weights, ornamented with jasper pendants

don't know where they found these, so I'm not sure if the color would have changed

(D) A black feather cape from a king’s burial vault

buried

(E) A multicolored woven sash found near the gravesite of a slave

buried

I also noticed that C was the only answer that did not specifically state where the artifact was found
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14 Jul 2008, 11:06
According to the source the answer is D.

2010mba wrote:
I'm picking C by POE

lordw wrote:
Determining the authenticity of purported pre-Columbian artifacts is never easy. Carbon-14 dating of these artifacts is often impossible due to contamination by radioactive palladium (which occurs naturally in the soils of Central and South America). However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts. First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding (To me this means they must be found in the ground). In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas (This is the second part and makes it seem the artifacts must be found in the ground since they must be exposed to magensium in the soil).

The criteria above would be LEAST useful in judging the authenticity of which of the following?

(A) An ax head of black obsidian, unearthed from a kitchen midden

found in the ground (unearthed), could have gridding

(B) A pottery bowl with a red ocher design, found in the ruins of a temple

found in the ruins of a temple so it's not likely someone discarded this after the temple was ruined, but the temple would have been exposed to the soil, so the pottery would be too

(C) A set of gold ear weights, ornamented with jasper pendants

don't know where they found these, so I'm not sure if the color would have changed

(D) A black feather cape from a king’s burial vault

buried

(E) A multicolored woven sash found near the gravesite of a slave

buried

I also noticed that C was the only answer that did not specifically state where the artifact was found
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14 Jul 2008, 11:15
IMO C.

All other options are unearthed one way or another.

In C author does not mention where the artifact was found??....which is important to deduce anything....
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14 Jul 2008, 11:20
lordw wrote:
Determining the authenticity of purported pre-Columbian artifacts is never easy. Carbon-14 dating of these artifacts is often impossible due to contamination by radioactive palladium (which occurs naturally in the soils of Central and South America). However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts. First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding. In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas.

The criteria above would be LEAST useful in judging the authenticity of which of the following?

We are asked to find sth with doesn't have
1) some unique scratch patterns
or
2) darkening in surface color

(A) An ax head of black obsidian, unearthed from a kitchen midden
(B) A pottery bowl with a red ocher design, found in the ruins of a temple
(C) A set of gold ear weights, ornamented with jasper pendants
(D) A black feather cape from a king’s burial vault
(E) A multicolored woven sash found near the gravesite of a slave

IMO : C
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14 Jul 2008, 11:24
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D

However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts.
(1)First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding.
(2)In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas.

The criteria above would be LEAST useful in judging the authenticity of which of the following?

(A) An ax head of black obsidian, unearthed from a kitchen midden
->(1)/(2) can be used
(B) A pottery bowl with a red ocher design, found in the ruins of a temple
->(1)/(2) can be used
(C) A set of gold ear weights, ornamented with jasper pendants
->(1)/(2) can be used
(D) A black feather cape from a king’s burial vault
->If the feather is in the vault , we cannot use (2) becuase the feather was not exposed to magnesium.
->Since its a feather how can you see thescratches.Cannot use (1)

(E) A multicolored woven sash found near the gravesite of a slave
->->(1)/(2) can be used
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14 Jul 2008, 11:29
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goalsnr wrote:
D

However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts.
(1)First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding.
(2)In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas.

The criteria above would be LEAST useful in judging the authenticity of which of the following?

(A) An ax head of black obsidian, unearthed from a kitchen midden
->(1)/(2) can be used
(B) A pottery bowl with a red ocher design, found in the ruins of a temple
->(1)/(2) can be used
(C) A set of gold ear weights, ornamented with jasper pendants
->(1)/(2) can be used
(D) A black feather cape from a king’s burial vault
->If the feather is in the vault , we cannot use (2) becuase the feather was not exposed to magnesium.
->Since its a feather how can you see thescratches.Cannot use (1)

(E) A multicolored woven sash found near the gravesite of a slave
->->(1)/(2) can be used

HOOOOOOLLLLLD that thought, how can you be sooo certain that just because the feather was found in a vault, it was not exposed to magnesium.....The vault could very well be a pit dug into the earth. Which would lead to magnesium exposure....

Secondly, cannot see scrathes on a feather?? ..... when cells can been seen via a microscope....seeing scratches on a feather would be a walk in the park....
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14 Jul 2008, 11:54
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Amazing! Tks.

goalsnr wrote:
D

However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts.
(1)First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding.
(2)In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas.

The criteria above would be LEAST useful in judging the authenticity of which of the following?

(A) An ax head of black obsidian, unearthed from a kitchen midden
->(1)/(2) can be used
(B) A pottery bowl with a red ocher design, found in the ruins of a temple
->(1)/(2) can be used
(C) A set of gold ear weights, ornamented with jasper pendants
->(1)/(2) can be used
(D) A black feather cape from a king’s burial vault
->If the feather is in the vault , we cannot use (2) becuase the feather was not exposed to magnesium.
->Since its a feather how can you see thescratches.Cannot use (1)

(E) A multicolored woven sash found near the gravesite of a slave
->->(1)/(2) can be used
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09 Aug 2010, 06:43
Went with D based on the same logic.

goalsnr wrote:
D

However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts.
(1)First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding.
(2)In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas.

The criteria above would be LEAST useful in judging the authenticity of which of the following?

(A) An ax head of black obsidian, unearthed from a kitchen midden
->(1)/(2) can be used
(B) A pottery bowl with a red ocher design, found in the ruins of a temple
->(1)/(2) can be used
(C) A set of gold ear weights, ornamented with jasper pendants
->(1)/(2) can be used
(D) A black feather cape from a king’s burial vault
->If the feather is in the vault , we cannot use (2) becuase the feather was not exposed to magnesium.
->Since its a feather how can you see thescratches.Cannot use (1)

(E) A multicolored woven sash found near the gravesite of a slave
->->(1)/(2) can be used

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09 Aug 2010, 17:46
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Hey All,

Lots of discussion on this one. Let's see what I can do...

Determining the authenticity of purported pre-Columbian artifacts is never easy. Carbon-14 dating of these artifacts is often impossible due to contamination by radioactive palladium (which occurs naturally in the soils of Central and South America). However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts. First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding. In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas.

The criteria above would be LEAST useful in judging the authenticity of which of the following?

Breakdown. We have two methods: Check earthquake-related gridding and check for magnesium darkening. Where will these fail?

(A) An ax head of black obsidian, unearthed from a kitchen midden
PROBLEM: Darkening wouldn't work here (because it's black), but gridding would still work (obsidian is just glassy rock).

(B) A pottery bowl with a red ocher design, found in the ruins of a temple
PROBLEM: Both gridding and darkening would work here.

(C) A set of gold ear weights, ornamented with jasper pendants
PROBLEM: Both gridding and darkening would work here.

(D) A black feather cape from a king’s burial vault
ANSWER: It's black, so you can't check darkening, and it's made of feathers, so there won't be any gridding on the surface.

(E) A multicolored woven sash found near the gravesite of a slave
ANSWER: Gridding wouldn't work here (fabric), but darkening still would.

The answer is definitely D. Fun!

-tommy
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09 Aug 2010, 17:47
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Aha. I just checked other people. I agree that the vault itself does not imply that it wasn't in the dirt. The issue is that it's black.

-t
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31 Aug 2010, 14:43
D +1
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01 Sep 2010, 01:17
tough one...
I have one question ... how you will distiguish between the grinding on axe by nature and by its use (as it is an axe)??? I have doubt
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17 Oct 2010, 05:59
isnt the burial part a necessary criteria in selecting the answer.if it is so then c shoould have been the answer
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05 Jul 2011, 04:50
I agree with Amit.

How can we deduce that the markings / gridding on the obsidian was caused by the earthquakes and not by the axe itself. Thereby, rendering Test A futile.

Further, obsidian means "A usually black or banded, hard volcanic glass that displays shiny, curved surfaces when fractured and is formed by rapid cooling of lava." So again the change in color will not be noticeable. Test B futile.

I went with A.

Any thoughts on the above?? thanks.
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10 Aug 2011, 05:04
its D
cos rather than D every statement refers to the first or 2nd criteria but D is a feather cap which is neither related to magnesium or to gridding...
that is wat i got!! correct me if i m wrong
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10 Aug 2011, 05:28
+1 for D.. Nice discussion!!
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10 Aug 2011, 06:13
D fits best
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10 Aug 2011, 06:37
D
Re: CR carbon 14   [#permalink] 10 Aug 2011, 06:37

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