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Question

Difficulty: MediumSequence of Events

Passage

Dr. Evelyn Chen adjusted the microscope, focusing on the cross-section of a deep-sea bamboo coral specimen retrieved from the Tasmanian Seamounts. The coral, *Keratoisis*, had lived for centuries, its skeletal nodes depositing concentric rings that functioned like tree rings, archiving the marine environment. Before Chen's 2024 expedition, the prevailing theory, published by Dr. Marcus Vance in 1998, asserted that the Southern Ocean had experienced a sudden, catastrophic cooling event in 1650. Vance had based his conclusion on fossilized bivalve shells gathered during his own landmark 1992 voyage. However, Chen’s newly acquired coral cores revealed a more gradual temperature decline. As she traced the rings outward from the coral's youth—which uranium-thorium dating placed at approximately 1580—she identified a series of severe storms around 1610 that had disrupted sediment deposition. This disruption, rather than a sustained global cooling, had caused the anomalous shell growth Vance observed. Chen realized that the climatic shift Vance attributed to 1650 had actually initiated decades earlier, during the coral's early growth phase, and had stabilized by the time the coral reached maturity in 1720.

According to the passage, the series of severe Southern Ocean storms occurred during which of the following timeframes?

  1. A
    after the bamboo coral reached maturity but before Vance’s landmark voyage
  2. B
    after Vance collected the fossilized shells but before he published his cooling theory
  3. before the bamboo coral reached maturity but after the coral began growingAnswer
  4. D
    before the bamboo coral began growing but after Vance published his cooling theory

Answer

The timeframe before the bamboo coral reached maturity but after the coral began growing.
The correct answer is the timeframe before the coral reached maturity but after it began growing. The passage indicates that the coral began growing around 1580 and reached maturity in 1720. The severe storms occurred around 1610, which falls chronologically between these two milestones.

Step-by-Step Solution

1
Identify the year of the severe Southern Ocean storms from the passage.
The passage states that the storms occurred around 1610.
Establishing the precise chronological placement of the storms is necessary to evaluate the options.
2
Determine the dates associated with the coral's lifecycle.
The coral began growing (its youth) around 1580 and reached maturity in 1720.
This bounds the timeline of the coral's life relative to the storms.
3
Compare the storm year (1610) with the coral's lifespan dates.
Since 1610 is after 1580 (onset of growth) and before 1720 (maturity), the storms occurred before the coral reached maturity but after it began growing.
This confirms the correct chronological relationship between the events.

Key Concept

Reconstructing the chronological sequence of historical and research events in a non-linear narrative.
Estimated Time:1m 30s
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Topics

Sequence of Events

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