Reading Comprehension

PT21 · S4 · P3 · Q17 Abiogenic Theory of Oil

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Since the early 1920s, most petroleum geologists have favored a biogenic theory for the formation of oil.

Topic

Theories about the origin of petroleum: biogenic vs. abiogenic

Framework

Old / New (with elements of Present Debate)

Main Point

The traditionally favored biogenic theory holds that oil is created from organic matter, but a competing abiogenic theory has emerged, suggesting that oil originated as hydrocarbons in the mantle and migrated upward. If the abiogenic theory is correct, it could mean there are undiscovered oil and gas reservoirs in unexpected places. Most Valuable Sentence: The last paragraph's first sentence sums up the significance:

P1: Background—Traditional View

Most geologists since the 1920s have thought that oil comes from buried organic matter that got transformed over long periods through heat and pressure.

P2: Introduction of Abiogenic Theory

A more recent, competing idea is that oil came not from dead plants and animals but from hydrocarbons that have been in the mantle since the earth formed. This oil would move upwards with methane gas through cracks in the earth.

P3: Scientific Debate and Evidence

Opponents of the abiogenic theory say hydrocarbons couldn’t survive the mantle’s heat, but supporters argue mantle conditions could allow it, pointing to the presence of diamonds (made of carbon) and experiments suggesting high pressure can preserve hydrocarbons.

17.

Which one of the following statements best expresses the main idea of the passage?

  1. Although the new abiogenic theory

    Contradicted: derived from

    The abiogenic theory is not at all derived from the conventional view. They start from pretty opposite precepts. Biogenic: oil comes from organic matter (dead life forms) Abiogenic: no, it doesn't. it doesn't come from biological stuff. it comes from hydrocarbon gases in the mantle.

    9% picked this

  2. The small number of drilling

    Wrong Emphasis Too Strong: minimal level

    There's no good reason for our main point answer to be centered around "the small number of drilling companies". They were not the main character of the passage. The passage's main character was the question of "where does oil come from" and the New answer of "maybe it comes from hydrocarbon gases that seep up from the mantle through cracks in the crust". This answer makes it sound like the author's main goal in writing this was to disparage the legitimacy of this new perspective, "The fact that so few people are acting on this new idea tells you how far-fetched it is". Our author is way more neutral, and, if anything, seems curious about whether this abiogenic theory may be correct.

    1% picked this

  3. Although the new abiogenic theory

    Too Strong

    Too Strong: superior Out of Scope: several enigmas Our author doesn't have a strong enough opinion on whether biogenic vs. abiogenic is the correct origin story of oil for us to support this answer. The author really never reveals any opinion or preference. The final paragraph says, "If this new theory is correct, there are interesting ramifications", but that's no indication that she thinks this new theory is correct. Also, "fails to explain several enigmas about oil reservoirs" doesn't match up with anything. There is one central enigma: where do oil reservoirs come from?

    2% picked this

  4. Correct

    Although it has yet to

    Why this is right

    The main clause is that "the new theory offers a plausible alternative to the conventional one". This nicely accords with our Old / New framework. The fact that these are "theories about the origin of oil" accords with our Present Debate framework. The introductory clause is not really important (it's probably there to make us like this answer a little bit less), but it is saying something accurate: the new drilling project hasn't gone far enough to be judged as support / refutation. Saying that abiogenic is a plausible alternative doesn't imply that it's more plausible. It just implies that the author takes it seriously. We can tell from the final paragraph that the author takes it seriously, since she talks through possible ramifications "if the abiogenic theory is correct". And the final sentence acknowledges that there is reason for the Swedes to be encouraged that the abiogenic theory is correct: Fueling their optimism further is the fact that ....

    Skill tested: Main Point · how this choice captures the passage's function is the move to repeat next time.

    85% picked this

  5. Having answered objections about higher

    Too Strong: broad acceptance

    There's no indication anywhere in the passage that the abiogenic theory has been broadly accepted by the scientific community. This answer also places way too much spotlight on one small objection (the objection was actually that temperatures were too high, and the abiogenic proponents answered that objection by saying that higher pressure would offset the high temperatures).

    3% picked this

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