According to a recent theory, Archean-age gold-quartz vein systems were formed more than two billion years ago from magmatic fluids that originated from molten granite-like bodies deep beneath the surface of the Earth. This theory is contrary to the widely held view that the systems were deposited from metamorphic fluids, that is, from fluids that formed during the dehydration of wet sedimentary rocks. The recently developed theory has considerable practical importance. Most of the gold deposits discovered during the original gold rushes were exposed at the Earth's surface and were found because they had shed trails of alluvial gold that were easily traced by simple prospecting methods. Although these same methods still lead to an occasional discovery, most deposits not yet discovered have gone undetected because they are buried and have no surface expression. The challenge in exploration is therefore to unravel the subsurface geology of an area and pinpoint the position of buried minerals. Methods widely used today include analysis of aerial images that yield a broad geological overview; geophysical techniques that provide data on the magnetic, electrical, and mineralogical properties of the rocks being investigated; and sensitive chemical tests that are able to detect the subtle chemical halos that often envelop mineralization. However, none of these high-technology methods are of any value if the sites to which they are applied have never mineralized, and to maximize the chances of discovery the explorer must therefore pay particular attention to selecting the ground formations most likely to be mineralized. Such ground selection relies to varying degrees on conceptual models, which take into account theoretical studies of relevant factors. These models are constructed primarily from empirical observations of known mineral deposits and from theories of ore-forming processes. The explorer uses the models to identify those geological features that are critical to the formation of the mineralization being modeled, and then tries to select areas for exploration that exhibit as many of the critical features as possible. 1 104. The author is primarily concerned with (A) advocating a return to an older methodology (B) explaining the importance of a recent theory (C) enumerating differences between two widely used methods (D) describing events leading to a discovery (E) challenging the assumptions on which a theory is based 2 105. According to the passage, the widely held view of Archean-age gold-quartz vein systems is that such systems (A) were formed from metamorphic fluids (B) originated in molten granite-like bodies (C) were formed from alluvial deposits (D) generally have surface expression (E) are not discoverable through chemical tests 3 106. The passage implies that which of the following steps would be the first performed by explorers who wish to maximize their chances of discovering gold? (A) Surveying several sites known to have been formed more than two billion years ago (B) Limiting exploration to sites known to have been formed from metamorphic fluid (C) Using an appropriate conceptual model to select a site for further exploration (D) Using geophysical methods to analyze rocks over a broad area (E) Limiting exploration to sites where alluvial gold has previously been found 4 107. Which of the following statements about discoveries of gold deposits is supported by information in the passage? (A) The number of gold discoveries made annually has increased between the time of the original gold rushes and the present. (B) New discoveries of gold deposits are likely to be the result of exploration techniques designed to locate buried mineralization. (C) It is unlikely that newly discovered gold deposits will ever yield as much as did those deposits discovered during the original gold rushes. (D) Modern explorers are divided on the question of the utility of simple prospecting methods as a source of new discoveries of gold deposits. (E) Models based on the theory that gold originated from magmatic fluids have already led to new discoveries of gold deposits. 5 108. It can be inferred from the passage that which of the following is easiest to detect? (A) A gold-quartz vein system originating in magmatic fluids (B) A gold-quartz vein system originating in metamorphic fluids (C) A gold deposit that is mixed with granite (D) A gold deposit that has shed alluvial gold (E) A gold deposit that exhibits chemical halos 6 109. The theory mentioned in lines 1-5 relates to the conceptual models discussed in the passage in which of the following ways? (A) It may furnish a valid account of ore-forming processes, and, hence, can support conceptual models that have great practical significance. (B) It suggests that certain geological formations, long believed to be mineralized, are in fact mineralized, thus confirming current conceptual models. (C) It suggests that there may not be enough similarity across Archean-age gold-quartz vein systems to warrant the formulation of conceptual models. (D) It corrects existing theories about the chemical halos of gold deposits, and thus provides a basis for correcting current conceptual models. (E) It suggests that simple prospecting methods still have a higher success rate in the discovery of gold deposits than do more modern methods. 7 110. According to the passage, methods of exploring for gold that are widely used today are based on which of the following facts? (A) Most of the Earth's remaining gold deposits are still molten. (B) Most of the Earth's remaining gold deposits are exposed at the surface. (C) Most of the Earth's remaining gold deposits are buried and have no surface expression. (D) Only one type of gold deposit warrants exploration, since the other types of gold deposits are found in regions difficult to reach. (E) Only one type of gold deposit warrants exploration, since the other types of gold deposits are unlikely to yield concentrated quantities of gold. 8 8. It can be inferred from the passage that the efficiency of model-based gold exploration depends on which of the following? I. The closeness of the match between the geological features identified by the model as critical and the actual geological features of a given area II. The degree to which the model chosen relies on empirical observation of known mineral deposits rather than on theories of ore-forming processes III. The degree to which the model chosen is based on an accurate description of the events leading to mineralization (A) I only (B) II only (C) I and II only (D) I and III only (E) I, II, and III [

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According to a recent theory, Archean-age gold-quartz vein systems wer

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8. It can be inferred from the passage that the efficiency of model-based gold exploration depends on which of the following?

I. The closeness of the match between the geological features identified by the model as critical and the actual geological features of a given area
II. The degree to which the model chosen relies on empirical observation of known mineral deposits rather than on theories of ore-forming processes
III. The degree to which the model chosen is based on an accurate description of the events leading to mineralization
(A) I only
(B) II only
(C) I and II only
(D) I and III only
(E) I, II, and III

Quote:

These models are constructed primarily from empirical observations of known mineral deposits and from theories of ore-forming processes. The explorer uses the models to identify those geological features that are critical to the formation of the mineralization being modeled, and then tries to select areas for exploration that exhibit as many of the critical features as possible.

I am also perplexed. How are empirical observations liked to "an accurate description of events"?
i am not able to extract III from the above paragraph. Can someone please explain it? GMATNinja VeritasKarishma EMPOWERgmatVerbal please suggest

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107. Which of the following statements about discoveries of gold deposits is supported by information in the passage?

(A) The number of gold discoveries made annually has increased between the time of the original gold rushes and the present.
(B) New discoveries of gold deposits are likely to be the result of exploration techniques designed to locate buried mineralization.
(C) It is unlikely that newly discovered gold deposits will ever yield as much as did those deposits discovered during the original gold rushes.
(D) Modern explorers are divided on the question of the utility of simple prospecting methods as a source of new discoveries of gold deposits.
(E) Models based on the theory that gold originated from magmatic fluids have already led to new discoveries of gold deposits.

I disagree with the OA being (B): New discoveries are also possible from Alluvial Trail on the surface.
I strongly feel (E) is the answer as the magmatic fluid has justified the Early Gold Rush discoveries.

Can experts please help here.

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Hi ShubhamPatil,

Quote:

(E) Models based on the theory that gold originated from magmatic fluids have already led to new discoveries of gold deposits.

E for Question 107, is incorrect, because it is no where mentioned in the passage that models based on the theory that gold originated from magmatic fluids have already led to new discoveries of gold deposits. What's mentioned is that these models are of practical importance and why, but whether these theories have already led to discoveries of gold cannot be inferred.

Line "Most of the gold deposits discovered during the original gold rushes were exposed at the Earth's surface and were found because they had shed trails of alluvial gold that were easily traced by simple prospecting methods.", does not imply that the theory that gold originated from magmatic fluids led to this discovery of Gold.

Thus E is the incorrect answer.

Option B can be inferred from the lines mentioned in the last para: "These models are constructed primarily from empirical observations of known mineral deposits and from theories of ore-forming processes. The explorer uses the models to identify those geological features that are critical to the formation of the mineralization being modeled, and then tries to select areas for exploration that exhibit as many of the critical features as possible.".

Hope This Helps.
Thanks.

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can anyone explain question number 109 ? I stuck between A & B

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VeritasKarishma
can anyone explain question number 109 ? I stuck between A & B

According to a recent theory, Archean-age gold-quartz vein systems were formed ... This theory is contrary to the widely held view that the systems were ...

... to maximize the chances of discovery the explorer must pay particular attention to selecting the ground formations most likely to be mineralized. Such ground selection relies to varying degrees on conceptual models, which take into account theoretical studies of relevant factors...

These models are constructed primarily from ... theories of ore-forming processes. The explorer uses the models to identify those geological features that are critical to the formation of the mineralization being modeled, and then tries to select areas for exploration that exhibit as many of the critical features as possible.

We discuss a new theory contrary to current theory.
Why are these theories relevant?

Because the explorers use models (based on theories) to identify where to look for gold. No matter how high tech your method, if you are not looking in the right place, you will never find gold. The right place to look for is decided on the basis of the models which are based on such theories. If the ore-forming theory is accurate, it will lead to better predictive models and hence more successful finds.

Hence, the theories have practical significance.

109. The theory mentioned in lines 1-5 relates to the conceptual models discussed in the passage in which of the following ways?

(A) It may furnish a valid account of ore-forming processes, and, hence, can support conceptual models that have great practical significance.

Correct. The theory may furnish a valid account of ore-forming process and the model will work better.

(B) It suggests that certain geological formations, long believed to be mineralized, are in fact mineralized, thus confirming current conceptual models.

All we know is that this new theory is contrary to current theory. How the two compare in the success of the conceptual model they support, we don't know.

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Official Explanation

104. The author is primarily concerned with

Difficulty Level: Medium

Explanation

Main idea

Examine the entire passage to find the author’s primary concern. An analysis of this passage shows that the author introduces a recent theory in the first paragraph, explains the practical importance of the theory in the second, and discusses the methods of exploring the theory makes possible in the third and fourth paragraphs. The author is primarily concerned with presenting a new theory and showing why it is important.

A. The only older methodology cited in the passage, simple prospecting methods, leads to only an occasional discovery (lines 15–17); there is no indication that the author favors this.

B. Correct. The author describes a recent theory of ore formation and discusses its importance.

C. Tree methods of exploration are described in the third paragraph, but diﬀerences among them are not discussed.

D. The passage describes a theory and the practice derived from it; it does not describe a series of events leading to a discovery.

E. The author describes two theories of ore formation in the first paragraph but does not challenge the assumptions on which either one is based.

The correct answer is B.

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Official Explanation

105. According to the passage, the widely held view of Archean-age gold-quartz vein systems is that such systems

Difficulty Level: Medium

Explanation

Supporting ideas

This question asks for information explicitly stated in the first paragraph where Archean-age gold-quartz vein systems are discussed. The recent theory is contrary to the widely held theory that Archean-age gold-quartz vein systems were deposited from metamorphic ﬂuids (lines 6–7).

A Correct. The widely held theory explains that the systems were deposited from metamorphic ﬂuids (line 7).

B. It is the recent theory that holds that the systems were formed from magmatic ﬂuids that originated from molten granite-like bodies (lines 3–4); the recent theory is not the widely held view.

C. Alluvial deposits are mentioned only in the context of simple prospecting methods (lines 14–16); there is nothing in the passage explicitly linking alluvial deposits to metamorphic ﬂuids.

D. Lines 17–19 explain that most deposits not yet discovered … have no surface expression, but there is no mention in the passage of widely held beliefs concerning surface expressions of the metamorphic ﬂuids.

E. Sensitive chemical tests are able to detect deposits where mineralization has occurred (lines 27–29).

The correct answer is A.

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Official Explanation

106. The passage implies that which of the following steps would be the first performed by explorers who wish to maximize their chances of discovering gold?

Difficulty Level: Medium

Explanation

Inference

Since the question uses the word implies, the answer will be an inference based on what the passage says about exploration. The third and fourth paragraphs describe the process of exploration. Te high-technology methods are of no use to the explorer if the sites have not mineralized, and to maximize the chances of discovery the explorer must therefore pay particular attention to selecting the ground formations most likely to be mineralized (lines 30–35). Conceptual models based on observation and ore-formation theories allow the explorer to identify the areas most likely to be mineralized (lines 39–46).

A. Nothing in the passage indicates that a large a portion of two-billion-year-old sites will have gold in them; it only indicates that if they are gold-quartz vein systems, they will be over two billion years old.

B. The widely held view, rather than the recent the theory that is the focus of the passage, argued that gold-quartz vein systems were formed from metamorphic ﬂuids. Te the passage says the recent theory has considerable practical importance, suggesting the benefits of applying the recent theory rather than this widely held view.

C Correct. Conceptual models lead the explorer to the sites most likely to have mineralized.

D. Geophysical techniques are of no use unless ground formations in an area have been mineralized (lines 24–32).

E. The simple prospecting methods that find alluvial gold lead to only an occasional discovery; most deposits not yet discovered … are buried (lines 15–19).

The correct answer is C.

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Official Explanation

107. Which of the following statements about discoveries of gold deposits is supported by information in the passage?

Difficulty Level: Easy

Explanation

Supporting ideas

This question requires consideration of explicit information throughout the passage. The second paragraph explains that most deposits not yet discovered … are buried (lines 17–19), so the explorer’s best means of discovering them is the use of conceptual models to identify the sites most likely to have buried minerals (lines 35–38). At that point, the explorer may use the high technology methods possible when buried mineralization is present (lines 22–29).

A. The passage does not discuss the number of gold discoveries.

B. Correct. Since most gold deposits are buried, explorers must find the sites most likely to contain buried minerals.

C. The passage does not discuss the yield of gold discoveries.

D. While simple prospecting methods lead only to an occasional discovery, modern explorers are not said to dispute their utility (lines 15–17).

E. The passage does not say that gold deposits have already been found by using the models based on this recent theory.

The correct answer is B.

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Official Explanation

108. It can be inferred from the passage that which of the following is easiest to detect?

Difficulty Level: Easy

Explanation

Application

To answer this question, apply what the passage says about gold deposits to the examples in the answer choices. Te second paragraph states that the gold deposits discovered during the gold rushes were exposed at the Earth’s surface; they were found because they had shed trails of alluvial gold that were easily traced by simple prospecting methods (lines 11–16). Most deposits have not been detected because they are buried and have no surface expression. Tus the simplest gold to find would be that in a deposit that had shed alluvial gold.

A. The recent theory holds that gold-quartz vein systems are formed from magmatic ﬂuids, but does not say that these systems have easily detectable surface expressions; the passage states that they form deep beneath the surface of Earth, which makes it unlikely that they will be easy to find.

B. The widely held view contends that goldquartz vein systems are formed from metamorphic ﬂuids, but does not say if these have easily detectable surface expressions.

C. The passage does not comment on gold deposits mixed with granite, although the recent theory does mention molten granitelike bodies deep beneath the surface of the Earth (lines 4–5).

D. Correct. Finding gold deposits that have shed alluvial gold at the Earth’s surface is far easier than finding buried gold deposits.

E. One complex, difcult subsurface exploration method involves chemical tests detecting the subtle chemical halos that surround mineralized areas; clearly this is not the easiest means of detecting gold deposits.

The correct answer is D.

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Official Explanation

109. The theory mentioned in lines 1-5 relates to the conceptual models discussed in the passage in which of the following ways?

Difficulty Level: Hard

Explanation

Logical structure

This question requires considering the conceptual models described in lines 35–41 in light of the recent theory (lines 1–5), which the author assures the reader has considerable practical importance (lines 10–11). The conceptual models are derived from observation and from theories of ore-forming processes. Therefore, the recent theory may explain ore formation in a way that leads to the development of an updated model, and that model may then aid in the discovery of gold deposits.

A. Correct. The theory provides an explanation of ore formation, which aids in creating a conceptual model that may help explorers find gold deposits.

B. The theory does not confirm models but contributes to forming them.

C. The practical value of the theory is that it can help to formulate models.

D. The theory does not challenge theories about chemical halos but rather contributes to the development of conceptual models that might allow for the broader application of chemical halos.

E. The theory does not compare methods of discovering gold deposits.

The correct answer is A.

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Official Explanation

110. According to the passage, methods of exploring for gold that are widely used today are based on which of the following facts?

Difficulty Level: Medium

Explanation

Supporting ideas

This question concerns factual information stated in the passage. In contrast to the gold deposits discovered at the Earth’s surface, most deposits not yet discovered have gone undetected because they are buried and have no surface expression (lines 17–19). The methods widely used today must search for buried minerals rather than minerals on the surface (lines 22–29).

A. The passage mentions neither molten gold nor the method to detect it.

B. The passage explicitly says that most deposits are buried.

C. Correct. The passage explicitly states that most gold deposits are buried, leaving no traces at the Earth’s surface.

D. The passage neither distinguishes between types of gold nor describes inaccessible regions.

E. The passage does not relate types of gold to yields of gold deposits.

The correct answer is C.

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8. It can be inferred from the passage that the efficiency of model-based gold exploration depends on which of the following?

III. The degree to which the model chosen is based on an accurate description of the events leading to mineralization -
How to infer 3 from the passage?
These models are constructed primarily from empirical observations of known mineral deposits and from theories of ore-forming processes.
Acc to passage, models are constructed from theories of ore-forming process. But ore forming process are not same as events leading to mineralization (given in option)
Can you please explain how it is relevant?

Thanks in advance!

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Ore-formation processes are the same as events leading to mineralization. The processes that led to the formation of ores are the same as the events that led to mineralization.

We have clues in the passage:

The challenge in exploration is therefore to unravel the subsurface geology of an area and pinpoint the position of buried minerals.
... detect the subtle chemical halos that often envelop mineralization. However, none of these high-technology methods are of any value if the sites to which they are applied have never mineralized, and to maximize the chances of discovery the explorer must therefore pay particular attention to selecting the ground formations most likely to be mineralized. Such ground selection relies to varying degrees on conceptual models, which take into account theoretical studies of relevant factors.

These models are constructed primarily from empirical observations of known mineral deposits and from theories of ore-forming processes. The explorer uses the models to identify those geological features that are critical to the formation of the mineralization being modeled ..

If the model is based on an accurate description of how ores were formed (or events that led to mineralization), then model based exploration is likely to be more successful.

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According to a recent theory, Archean-age gold-quartz vein systems were formed more than two billion years ago from magmatic fluids that originated from molten granite-like bodies deep beneath the surface of the Earth. This theory is contrary to the widely held view that the systems were deposited from metamorphic fluids, that is, from fluids that formed during the dehydration of wet sedimentary rocks.

The recently developed theory has considerable practical importance. Most of the gold deposits discovered during the original gold rushes were exposed at the Earth's surface and were found because they had shed trails of alluvial gold that were easily traced by simple prospecting methods. Although these same methods still lead to an occasional discovery, most deposits not yet discovered have gone undetected because they are buried and have no surface expression.

The challenge in exploration is therefore to unravel the subsurface geology of an area and pinpoint the position of buried minerals. Methods widely used today include analysis of aerial images that yield a broad geological overview; geophysical techniques that provide data on the magnetic, electrical, and mineralogical properties of the rocks being investigated; and sensitive chemical tests that are able to detect the subtle chemical halos that often envelop mineralization. However, none of these high-technology methods are of any value if the sites to which they are applied have never mineralized, and to maximize the chances of discovery the explorer must therefore pay particular attention to selecting the ground formations most likely to be mineralized. Such ground selection relies to varying degrees on conceptual models, which take into account theoretical studies of relevant factors.

These models are constructed primarily from empirical observations of known mineral deposits and from theories of ore-forming processes. The explorer uses the models to identify those geological features that are critical to the formation of the mineralization being modeled, and then tries to select areas for exploration that exhibit as many of the critical features as possible.

Hi experts AndrewN IanStewart AjiteshArun zhanbo

I felt a sense of community to come back as a break from my TOEFL practice, but I also once again felt the mighty power of GMAT RC questions. I am confused about the Question 7, since I do not feel interested at any of the five options even though I have checked all previous posts and the official explanations. Could you experts share some thoughts when you have time please? Thank you!

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109. The theory mentioned in lines 1-5 relates to the conceptual models discussed in the passage in which of the following ways?
(A) It may furnish a valid account of ore-forming processes, and, hence, can support conceptual models that have great practical significance.
(B) It suggests that certain geological formations, long believed to be mineralized, are in fact mineralized, thus confirming current conceptual models.
(C) It suggests that there may not be enough similarity across Archean-age gold-quartz vein systems to warrant the formulation of conceptual models.
(D) It corrects existing theories about the chemical halos of gold deposits, and thus provides a basis for correcting current conceptual models.
(E) It suggests that simple prospecting methods still have a higher success rate in the discovery of gold deposits than do more modern methods.

The theory mentioned in line 1-5 is the recent theory, the core of this passage. This recent theory is also the antecedent of the pronoun "It" appearing in all five options. On the other hand, the conceptual models show in the end of the third paragraph and the final paragraph.

Before I checked the options, my understanding for the relationship between the recent theory and the models was quite simple: the recent theory indicates that some gold is buried deep beneath Earth, and in order to pinpoint the locations of the buried gold, people need to use the models in addition to high-tech prospecting methods. So basically, these models are helpful for people who believe in the recent theory and attempt to find golds. But we could not know whether the recent theory plays a role in the development of these models, or the other way around, because it is not mentioned in the passage. These were my thinking lines.

But none of the five options presents such a straightforward relationship as mine, and the correct answer, (A), looks quite convoluted to me. I hope to analyze one option at a time, but first I hope to concentrate on the option (A):

(A) It may furnish a valid account of ore-forming processes, and, hence, can support conceptual models that have great practical significance.

From the passage we know that "It," or the recent theory, contends that Archean-age gold-quartz vein systems were formed more than two billion years ago from magmatic fluids that originated from molten granite-like bodies deep beneath the surface of the Earth. And we know that this recent view is contrary to the widely held view that the systems were deposited from metamorphic fluids. (Although the recent theory also appears in other paragraphs, its exact description rests only in the first paragraph.)

Meanwhile, from the passage we know that the conceptual models consider theoretical studies of relevant factors, and are constructed primarily from empirical observations of known mineral deposits and from theories of ore-forming processes. The models are used to identify geological features so people can select the ground formations most likely to be mineralized.

I thought that "theoretical studies of relevant factors" and "theories of ore-forming processes" refer to other studies than the recent theory mentioned in the first paragraph, because: (1) the recent theory is about "gold-quartz vein systems" and I am unsure whether ore is part of the systems; (2) in light of the sequence of the paragraphs, I am under the impression that the recent theory is the motive for people's trying to prospect for the underground world, not the tool used in the process.

The option (A) will be more acceptable to me if the recent theory is one of the theories on which the models are constructed. But, I still do not get why the recent theory can provide a valid description of ore-forming processes. Neither can I understand the following official explanations colored in green color.

Sajjad1994

Official Explanation
109. The theory mentioned in lines 1-5 relates to the conceptual models discussed in the passage in which of the following ways?

This question requires considering the conceptual models described in lines 35–41 in light of the recent theory (lines 1–5), which the author assures the reader has considerable practical importance (lines 10–11). The conceptual models are derived from observation and from theories of ore-forming processes. Therefore, the recent theory may explain ore formation in a way that leads to the development of an updated model, and that model may then aid in the discovery of gold deposits.

A. Correct. The theory provides an explanation of ore formation, which aids in creating a conceptual model that may help explorers find gold deposits.

*
Besides, could I check the reasons of elimination of other four options?

(B) It suggests that certain geological formations, long believed to be mineralized, are in fact mineralized, thus confirming current conceptual models.
-->The recent theory is just a theory, so it cannot suggest that some things are indeed mineralized, right?

(C) It suggests that there may not be enough similarity across Archean-age gold-quartz vein systems to warrant the formulation of conceptual models.
-->The passage does not give any suggestion in this regard.

(D) It corrects existing theories about the chemical halos of gold deposits, and thus provides a basis for correcting current conceptual models.
-->Chemical halos are mentioned in descriptions of the high-tech prospecting methods, but the theories about chemical halos are not addressed in the passage, let alone correction to the theories.

(E) It suggests that simple prospecting methods still have a higher success rate in the discovery of gold deposits than do more modern methods.
-->I actually felt slightly interested at this option, since there seems to be several challenges in exploration of the deep buried gold (the passage indeed uses the word "challenge" in the beginning of the third paragraph.) But the adverb "still" in (E) is a red flag, because we know that most remaining gold deposits are deep buried and undetected under the simple prospecting methods.

Thank you for your time and thoughts!
Thank you for helping me learn.

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11 Jul 2022, 12:38

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Hello, GraceSCKao. I think you are reading into the text too much. (Also, this is question 6, not 7. It took me a minute to figure out that what I was prepared to write had nothing to do with the question you quoted above.)

I did not read much beyond the first paragraph and the topic sentence of the second paragraph:

Quote:

The passage tells us outright that the newer theory has considerable—or great, if you prefer the phrasing of answer choice (A)—practical importance—or significance in answer choice (A). Thus, the latter half of (A) checks out. As long the part before the comma does not run afoul of the passage, we have a reasonable answer.

Quote:

Now, in what way does the recently developed theory differ from the widely held view with regards to ore-forming processes? Luckily for us, we see the contrast present in paragraph one in overlapping language that mentions fluids. Preserve as much of the language of the passage as possible, even in truncated form.

Recent theory—[systems] were formed from magmatic fluids

Widely held [theory]—systems were deposited from metamorphic fluids

Now, we do not need to be geologists to know the difference between these types of molten rock. The passage takes care of the definitions for us, more or less. The recent theory involves gold-quartz and granite-like bodies; the widely held view involves the dehydration of wet sedimentary rocks. Since the rest of the passage discusses gold, and the final paragraph mentions theories of ore-forming processes, we can put the two pieces of information together and reason that ore-forming processes must refer in some sense to gold-forming processes. Answer choice (A) looks even better than before. The more recent theory may—not will—better describe the ore-forming processes than the more widely held view.

As for the other options, I think they are easier to disprove, and you have done a fine job to that end already. Answer choice (B) seems to align the two conceptual models, rather than tilt the balance one way or the other. Meanwhile, (E) is baseless once it hits still have a higher success rate. Indeed, the last sentence of paragraph two seems to fly in the face of what (E) says: Although these same [simple prospecting] methods still lead to an occasional discovery, most deposits not yet discovered have gone undetected because they are buried and have no surface expression. There is no direct comparison made between how many gold excavations have taken place using more modern techniques, but any way we look at it, we cannot simply drum up the comparison in (E).

Show SpoilerMy Timer Result (28 October 2021)

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Screen Shot 2022-07-11 at 15.07.41.png [ 39.16 KiB | Viewed 3793 times ]

Perhaps the question makes more sense now. Thank you for thinking to ask.

- Andrew

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27 Aug 2022, 20:09

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Hi, Can an expert weigh in on why option D is the correct choice for the last question in the passage?
I have read through all explanations on the thread but just cannot understand where the passage talks about "the degree to which the model chosen is based on an accurate description of the events leading to mineralization". Where even am I supposed to look in the passage to prove this right? and I thought that ore forming processes influenced the conceptual models, where did mineralization come from?
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28 Aug 2022, 04:04

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sv2023

The question is about using models. The first question we have to answer, therefore, is What is the basic purpose/function of the models?
That's found near the end of the next-to-last paragraph:
the explorer must ... pay particular attention to selecting the ground formations most likely to be mineralized. Such ground selection relies ... on models

That's what these 'models' are actually supposed to DO: They're supposed to help explorers pick places where mineralization is most likely to happen.

The models don't do anything else (...not in this passage, at least).
So, what is being modeled?
Well, if the models are supposed to guide people to the places where mineralization will probably happen, then, they must be models of whatever makes mineralization happen.
That's a yes on part (iii).

The take-home point here is how close this answer is to the text. As the blue and green colors illustrate, there are only trivial reasoning steps between the text reference and the answer. For RC detail questions, the actual challenge lies in FIGURING OUT WHAT TO FIND IN THE TEXT and then FINDING THAT STUFF in the text. Once you've found the correct stuff, any remaining steps of logic/reasoning should be trivial.
In other words, if you're starting to construct a non-trivial, substantive FURTHER argument FROM the text reference... STOP! You should not have to do that; you're almost certainly leading yourself astray if you do.

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30 Aug 2022, 00:35

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Paragraph 1: Two theories in contrast as to how were the vein-systems formed. (Recent Theory: Magmatic Fluids; Widely Held View: Metamorphic Fluids)
Paragraph 2: Explains why the Author thinks recent theory has practical importance (Uses example of gold that was exposed on Earth’s surface discovered during gold rush found easily by simple prospecting methods, which don’t work on deposits that have no surface expression)
Paragraph 3: Points out the challenge in exploration of minerals. Outlines the methods used today. Explains why the methods of today aren’t of any value to sites that have never mineralized and offers a solution
Paragraph 4: Explains how the models mentioned in P3 are constructed and applied.

All this passage is about is the practical importance of a recent theory about how Archean-age gold-quartz vein systems were formed