Volcanic rock that forms as fluid lava chills rapidly is called pillow

2. In the passage, the author is primarily interested in

Difficulty Level: 700

Explanation

The passage discusses a geological phenomenon called "pillow lava," which forms when fluid lava chills rapidly. The process of rapid chilling occurs when lava erupts directly into water (or beneath ice) or when it flows across a shoreline and into a body of water. However, the term "pillow lava" is not as straightforward as it may seem, and geologists disagree on its characterization.

The main point of the passage is to address the controversy surrounding the definition and appearance of pillow lava. Some geologists describe it as discrete, ellipsoidal masses, while others see it as a tangled mass of cylindrical, interconnected flow lobes. The author suggests that this disagreement is likely due to unwarranted extrapolations made from two-dimensional cross-sections of eroded pillows in land outcroppings. The passage explains that any cross-section cut through a tangled mass of interconnected flow lobes would appear as discrete ellipsoidal masses, which can lead to confusion in defining the true geometry of pillowed flows and understanding their mode of origin.

The author emphasizes the need for adequate three-dimensional images of intact pillows to properly define the true geometry of pillow lava and clarify its mode of formation. The term "pillow" itself, which implies discrete masses, is questioned as a possible misnomer.

To summarize:

(A) Analyzing the source of a scientific controversy:
The author discusses the differing views among geologists regarding the nature of pillow lava and attributes the controversy to unwarranted extrapolations from two-dimensional cross-sections.

(B) Criticizing some geologists' methodology:
While the passage points out disagreements among geologists, it does not explicitly criticize their methodology.

(C) Pointing out the flaws in a geological study:
The passage does point out the limitations of relying on two-dimensional cross-sections to interpret the nature of pillow lava, but it does not focus on a specific geological study's flaws.

(D) Proposing a new theory to explain existing scientific evidence:
The passage does not propose a new theory but rather discusses the need for better three-dimensional images to accurately understand pillow lava.

(E) Describing a physical phenomenon:
While the passage does describe the physical phenomenon of pillow lava, its primary focus is on the controversy surrounding its definition and appearance, not merely describing the phenomenon itself.

Therefore, the correct answer is (A) analyzing the source of a scientific controversy.

Answer: A