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05 Apr 2020, 09:06
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Question 1
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
52% (02:55) correct
48%
(02:54) wrong
based on 625
sessions
History
Date
Time
Result
Not Attempted Yet
Question 2
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
85%
(hard)
Question Stats:
39% (01:34) correct 61%
(01:29) wrong
based on 607
sessions
History
Date
Time
Result
Not Attempted Yet
Question 3
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
95%
(hard)
Question Stats:
40% (01:53) correct 60%
(01:55) wrong
based on 580
sessions
History
Date
Time
Result
Not Attempted Yet
Project RC Butler 2020 - Participate and win GMAT Club Tests.
Passage # 10, Date: 05-Apr-2020
This post is a part of Project RC Butler 2020. Click here for Details
Passage # 10, Date: 05-Apr-2020
This post is a part of Project RC Butler 2020. Click here for Details
For absolute dating of archeological artifacts, the radiocarbon method emerged during the latter half of the twentieth century as the most reliable and precise method. The results of obsidian (volcanic glass) dating, a method based on the belief that newly exposed obsidian surfaces absorb moisture from the surrounding atmosphere at a constant rate, proved uneven. It was initially thought that the thickness of the hydration layer would provide a means of calculating the time elapsed since the fresh surface was made. But this method failed to account for the chemical variability in the physical and chemical mechanism of obsidian hydration. Moreover, each geographic source presented unique chemical characteristics, necessitating a trace element analysis for each such source. Yet, despite its limitations, obsidian dating helped archeologists identify the sources of many obsidian artifacts and to identify in turn ancient exchange networks for the flow of goods. Nor were ceramic studies and fluoride analysis supplanted entirely by the radiocarbon method, which in use allows for field labeling and laboratory errors, as well as sample contamination. In addition, in the 1970s dendrochronological (tree-ring) studies on the bristlecone pine showed that deviation from radiocarbon values increases as one moves back in time. Eventually calibration curves were developed to account for this phenomenon; but in the archeological literature we still find dual references to radiocarbon and sidereal, or calendar, time.
1. Based on the information in the passage, which of the following is LEAST likely to have been a means of dating archeological artifacts?
(A) Ceramics studies
(B) Radiocarbon dating
(C) Dendrochronological studies
(D) Fluoride analysis
(E) Obsidian hydration-layer analysis
(A) Ceramics studies
(B) Radiocarbon dating
(C) Dendrochronological studies
(D) Fluoride analysis
(E) Obsidian hydration-layer analysis
2. In the passage, the author mentions all of the following as problems with radiocarbon dating EXCEPT:
(A) disparities with the calendar dating system.
(B) deterioration of samples.
(C) identification errors by archeological field workers.
(D) contamination of artifacts.
(E) mistakes by laboratory workers.
(A) disparities with the calendar dating system.
(B) deterioration of samples.
(C) identification errors by archeological field workers.
(D) contamination of artifacts.
(E) mistakes by laboratory workers.
3. With which of the following statements would the passage’s author most likely agree?
(A) The greater the time that has elapsed since exposure of obsidian surface to moisture the less reliable the results of obsidian dating.
(B) The hydration layer accumulating through obsidian moisture absorption varies in thickness depending on the amount of surface area exposed to moisture.
(C) The unpredictability of the obsidian hydration process renders the obsidian dating method roblematic as a means of determining historical trade routes.
(D) The results of obsidian dating are as reliable and precise as those of fluoride analysis only if trace element analysis is performed for the geographic source of the obsidian.
(E) An obsidian artifact can be reliably dated using the obsidian method only if certain environmental conditions where the artifact was found are considered.
(A) The greater the time that has elapsed since exposure of obsidian surface to moisture the less reliable the results of obsidian dating.
(B) The hydration layer accumulating through obsidian moisture absorption varies in thickness depending on the amount of surface area exposed to moisture.
(C) The unpredictability of the obsidian hydration process renders the obsidian dating method roblematic as a means of determining historical trade routes.
(D) The results of obsidian dating are as reliable and precise as those of fluoride analysis only if trace element analysis is performed for the geographic source of the obsidian.
(E) An obsidian artifact can be reliably dated using the obsidian method only if certain environmental conditions where the artifact was found are considered.
Source: Master GMAT
05 Apr 2020, 13:20
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Answers are in bold.
1. Based on the information in the passage, which of the following is LEAST likely to have been a means of dating archeological artifacts?
(A) Ceramics studies
(B) Radiocarbon dating
(C) Dendrochronological studies
(D) Fluoride analysis
(E) Obsidian hydration-layer analysis
Explanation of question 1:
This is a LEAST question. Least likely to be used for dating artifacts. We know for a fact that (E) Obsidian is unreliable. We keep this for further analysis. Choices A and D are stated together and are at the "same level". By same level whatever there reliability is, they would be same. As it turns out they are also reliable. So A and D are out.
B Radiaocarbon dating is the most reliable, definitely out.
Choice C - Dendrochronological is also unreliable as evident from the text. Is it more unreliable that Obsidian? Well actually Obsidian is atleast used to date artifacts, however, no such reference is made for the dendrochronological one. It is just referred in the text that it deviates from radiocarbon. So, C is our answer.
_________________________________________________________________________________________________________________________________
2. In the passage, the author mentions all of the following as problems with radiocarbon dating EXCEPT:
(A) disparities with the calendar dating system.
(B) deterioration of samples.
(C) identification errors by archeological field workers.
(D) contamination of artifacts.
(E) mistakes by laboratory workers.
Explanation of question 2:
From the passage - "...radiocarbon method, which in use allows for field labeling and laboratory errors, as well as sample contamination."
Easy peasy, C, D, E are straight out. That was not hard was it!
A - last part of the passage refers to the difference of radio with calender dating. Out.
Left with B. Deterioration is not mentioned. B is our answer.
_________________________________________________________________________________________________________________________________
3. With which of the following statements would the passage’s author most likely agree?
(A) The greater the time that has elapsed since exposure of obsidian surface to moisture the less reliable the results of obsidian dating.
(B) The hydration layer accumulating through obsidian moisture absorption varies in thickness depending on the amount of surface area exposed to moisture.
(C) The unpredictability of the obsidian hydration process renders the obsidian dating method problematic as a means of determining historical trade routes.
(D) The results of obsidian dating are as reliable and precise as those of fluoride analysis only if trace element analysis is performed for the geographic source of the obsidian.
(E) An obsidian artifact can be reliably dated using the obsidian method only if certain environmental conditions where the artifact was found are considered.
Explanation of question 3:
We have to use POE for this, no choice. Lets go..
A - nope, not mentioned how obsidian would fare with age.
B - It does mention the word physical, so you think can this be our surface area. Wait a sec! it says "chemical variability in the physical and chemical mechanism". It is the a part of the chemical variability. Nice try to fool me. Out!
C - In fact you can use obsidian for determining ancient trade routes. So this is not our answer.
D - Absolutely not. Obsidian is unreliable. Flouride is quite good, not as good as radiocarbon but a worthy opponent!
E - Must be this choice, but lets delve into it. Oh yes if we know the trace element for the given source, we can reliable use obsidian to date. E is our answer.
1. Based on the information in the passage, which of the following is LEAST likely to have been a means of dating archeological artifacts?
(A) Ceramics studies
(B) Radiocarbon dating
(C) Dendrochronological studies
(D) Fluoride analysis
(E) Obsidian hydration-layer analysis
Explanation of question 1:
This is a LEAST question. Least likely to be used for dating artifacts. We know for a fact that (E) Obsidian is unreliable. We keep this for further analysis. Choices A and D are stated together and are at the "same level". By same level whatever there reliability is, they would be same. As it turns out they are also reliable. So A and D are out.
B Radiaocarbon dating is the most reliable, definitely out.
Choice C - Dendrochronological is also unreliable as evident from the text. Is it more unreliable that Obsidian? Well actually Obsidian is atleast used to date artifacts, however, no such reference is made for the dendrochronological one. It is just referred in the text that it deviates from radiocarbon. So, C is our answer.
_________________________________________________________________________________________________________________________________
2. In the passage, the author mentions all of the following as problems with radiocarbon dating EXCEPT:
(A) disparities with the calendar dating system.
(B) deterioration of samples.
(C) identification errors by archeological field workers.
(D) contamination of artifacts.
(E) mistakes by laboratory workers.
Explanation of question 2:
From the passage - "...radiocarbon method, which in use allows for field labeling and laboratory errors, as well as sample contamination."
Easy peasy, C, D, E are straight out. That was not hard was it!
A - last part of the passage refers to the difference of radio with calender dating. Out.
Left with B. Deterioration is not mentioned. B is our answer.
_________________________________________________________________________________________________________________________________
3. With which of the following statements would the passage’s author most likely agree?
(A) The greater the time that has elapsed since exposure of obsidian surface to moisture the less reliable the results of obsidian dating.
(B) The hydration layer accumulating through obsidian moisture absorption varies in thickness depending on the amount of surface area exposed to moisture.
(C) The unpredictability of the obsidian hydration process renders the obsidian dating method problematic as a means of determining historical trade routes.
(D) The results of obsidian dating are as reliable and precise as those of fluoride analysis only if trace element analysis is performed for the geographic source of the obsidian.
(E) An obsidian artifact can be reliably dated using the obsidian method only if certain environmental conditions where the artifact was found are considered.
Explanation of question 3:
We have to use POE for this, no choice. Lets go..
A - nope, not mentioned how obsidian would fare with age.
B - It does mention the word physical, so you think can this be our surface area. Wait a sec! it says "chemical variability in the physical and chemical mechanism". It is the a part of the chemical variability. Nice try to fool me. Out!
C - In fact you can use obsidian for determining ancient trade routes. So this is not our answer.
D - Absolutely not. Obsidian is unreliable. Flouride is quite good, not as good as radiocarbon but a worthy opponent!
E - Must be this choice, but lets delve into it. Oh yes if we know the trace element for the given source, we can reliable use obsidian to date. E is our answer.
General Discussion
05 Apr 2020, 12:56
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1) Radiocarbon dating is the ‘most reliable and precise method’.
Obsidian-hydration layer analysis, ‘despite its limitations, …helped archaeologists identify the sources of many obsidian artifacts…’ nor did it supplant ceramic studies and fluoride analysis which are mentioned together in one sentence.
Dendrochronological studies were used to correct for the deviation of radiocarbon values by use of calibration curves hence is in itself not a means of dating archaeological artifacts but rather a phenomenon.
2) Three problems -field labeling, lab errors and sample contamination- are mentioned in the sentence beginning with ‘Nor were ceramic studies and fluoride analysis…, which in use allows for field labeling and lab errors, as well as sample contamination.’
Disparities with the calendar system is also mentioned as a problem and this is corrected through dendrochronological studies. Deterioration of samples is not mentioned thus B) is the answer.
3) Through POE, A) is the correct answer.
B) Nowhere does the passage talk about surface area. Incorrect.
C) ‘Despite its limitations, obsidian dating helped archaeologists identify the sources of many obsidian artifacts and to identify in turn ancient exchange networks for the flow of goods.’ Therefore, obsidian dating was not problematic when it came to determining historical trade routes. Incorrect.
D) The comparison of the reliability and preciseness between fluoride analysis and obsidian dating has not been covered in the passage. Incorrect.
E) The phrase ‘only if’ makes this answer wrong. We have already been given instances in the passage when obsidian dating was sufficiently reliable as outlined above. Incorrect.
This leaves A) to be correct. The reliability of obsidian dating after exposure has been put into question. ‘It was initially thought that the thickness of the hydration layer would provide a means of calculating the time elapsed since the fresh surface was made. But this method failed to account for the chemical variability in the physical and chemical mechanism of obsidian hydration. Moreover, each geographic source presented unique chemical characteristics, necessitating a trace element analysis for each such source.’ Correct
Obsidian-hydration layer analysis, ‘despite its limitations, …helped archaeologists identify the sources of many obsidian artifacts…’ nor did it supplant ceramic studies and fluoride analysis which are mentioned together in one sentence.
Dendrochronological studies were used to correct for the deviation of radiocarbon values by use of calibration curves hence is in itself not a means of dating archaeological artifacts but rather a phenomenon.
2) Three problems -field labeling, lab errors and sample contamination- are mentioned in the sentence beginning with ‘Nor were ceramic studies and fluoride analysis…, which in use allows for field labeling and lab errors, as well as sample contamination.’
Disparities with the calendar system is also mentioned as a problem and this is corrected through dendrochronological studies. Deterioration of samples is not mentioned thus B) is the answer.
3) Through POE, A) is the correct answer.
B) Nowhere does the passage talk about surface area. Incorrect.
C) ‘Despite its limitations, obsidian dating helped archaeologists identify the sources of many obsidian artifacts and to identify in turn ancient exchange networks for the flow of goods.’ Therefore, obsidian dating was not problematic when it came to determining historical trade routes. Incorrect.
D) The comparison of the reliability and preciseness between fluoride analysis and obsidian dating has not been covered in the passage. Incorrect.
E) The phrase ‘only if’ makes this answer wrong. We have already been given instances in the passage when obsidian dating was sufficiently reliable as outlined above. Incorrect.
This leaves A) to be correct. The reliability of obsidian dating after exposure has been put into question. ‘It was initially thought that the thickness of the hydration layer would provide a means of calculating the time elapsed since the fresh surface was made. But this method failed to account for the chemical variability in the physical and chemical mechanism of obsidian hydration. Moreover, each geographic source presented unique chemical characteristics, necessitating a trace element analysis for each such source.’ Correct
