Question

Difficulty: MediumInferences and Implicit Meaning

In the mid-1950s, cartographer Marie Tharp identified a prominent V-shaped rift valley running continuously along the axis of the Mid-Atlantic Ridge while constructing bathymetric maps from oceanic echo-sounding profiles. Her collaborator, geologist Bruce Heezen, initially dismissed her interpretation of the rift, attributing the topography to artifactual errors in sonar data or localized volcanic scouring. At the time, mainstream American geophysics was dominated by fixist paradigms that viewed continental positions as permanently fixed; acknowledging a continuous global mid-ocean rift implied large-scale tension and crustal spreading, directly supporting Alfred Wegener’s controversial hypothesis of continental drift. It was only after independent seismic data demonstrated a precise alignment between shallow earthquake epicenters and Tharp’s mapped rift zone that Heezen accepted the feature's existence. Consequently, Tharp’s bathymetric synthesis provided pivotal empirical support for modern plate tectonics, though her early contribution was obscured by contemporary institutional biases and theoretical resistance.

Based on the passage, the passage implies which of the following regarding the geophysical community's initial reluctance to accept Tharp's identification of the rift valley?

  1. It was influenced in part by adherence to established geological frameworks that rejected horizontal crustal movement.Answer
  2. B
    It resulted primarily from documented instrumental defects in the bathymetric echo-sounding equipment used during the 1950s.
  3. C
    It completely prevented the publication of Tharp's oceanographic maps in scientific journals during her lifetime.
  4. D
    It was resolved only when Tharp collected additional echo-sounding profiles from the Pacific Ocean basin.
  5. E
    It prompted Bruce Heezen to formulate a new theoretical model that synthesized volcanic scouring with continental drift.

Answer

The initial reluctance to accept the rift valley was influenced in part by adherence to established geological frameworks that rejected horizontal crustal movement.
The correct answer is supported by the text's explanation that mainstream geophysics adhered to fixist paradigms (holding that continents are stationary) and that the rift implied continental drift. Therefore, the scientific community's resistance was logically rooted in part in their commitment to existing models that denied horizontal crustal motion.

Step-by-Step Solution

1
Analyze the passage for references to the geophysical community's theoretical background and stance on continental movement.
The passage states that mainstream American geophysics was dominated by fixist paradigms viewing continental positions as permanently fixed.
Establishing the prevailing scientific consensus provides context for why new evidence was met with skepticism.
2
Connect the theoretical background to the implication of Tharp's discovery.
Acknowledging the continuous mid-ocean rift implied crustal spreading and supported continental drift, which contradicted the dominant fixist paradigm.
Inference questions require recognizing unstated logical connections between facts presented in the text.
3
Evaluate the choices to find the statement logically supported by these passage facts.
The choice noting that skepticism was influenced by commitment to frameworks rejecting horizontal crustal movement accurately captures this implicit relationship.
Valid inferences must stay strictly within the bounds of passage evidence without overgeneralizing or misrepresenting details.

Key Concept

Identifying implicit cause-effect relationships and underlying theoretical assumptions supported by text evidence.
Rate this question