Examkin

Soru

Zorluk: ZorMust Be True / Most Strongly Supported

Paleoclimatologists analyzing polar ice cores have established the following:

• Every polar ice core segment that exhibits an anomalous sulfate spike without an accompanying basaltic cryptotephra deposit was formed during a period of non-explosive effusive volcanism.
• In the Amundsen-Scott ice core, every segment corresponding to the mid-Holocene climatic anomaly contains either a basaltic cryptotephra deposit or a high concentration of micro-meteoritic iridium, but not both.
• No polar ice core segment containing a high concentration of micro-meteoritic iridium was formed during a period of non-explosive effusive volcanism.
• Sample AS-442 is a segment from the Amundsen-Scott ice core that corresponds to the mid-Holocene climatic anomaly and exhibits an anomalous sulfate spike.

If the statements above are true, which one of the following must be true?

  1. A
    Sample AS-442 was formed during a period of non-explosive effusive volcanism.
  2. B
    Any polar ice core segment formed during a period of non-explosive effusive volcanism exhibits an anomalous sulfate spike.
  3. Sample AS-442 contains a basaltic cryptotephra deposit.Cevap
  4. D
    Every segment in the Amundsen-Scott ice core that exhibits an anomalous sulfate spike corresponds to the mid-Holocene climatic anomaly.
  5. E
    High concentrations of micro-meteoritic iridium in polar ice cores are caused exclusively by explosive volcanic eruptions.

Cevap

Sample AS-442 contains a basaltic cryptotephra deposit.
The deduction proceeds by indirect proof. Sample AS-442 corresponds to the mid-Holocene anomaly, meaning it must have either basaltic cryptotephra or high iridium, but not both. If sample AS-442 did not contain basaltic cryptotephra, it would necessarily contain high iridium. Under this scenario, because it has an anomalous sulfate spike without basaltic cryptotephra, it would have to be formed during non-explosive effusive volcanism (by the first premise). However, the third premise establishes that containing high iridium strictly precludes being formed during non-explosive effusive volcanism. Because this creates an impossible contradiction, the initial assumption must be false: sample AS-442 must contain a basaltic cryptotephra deposit.

Adım Adım Çözüm

1
Identify the known properties of sample AS-442 from the stimulus.
Sample AS-442 is from the Amundsen-Scott core, corresponds to the mid-Holocene climatic anomaly, and exhibits an anomalous sulfate spike.
Establishing the initial factual conditions sets the boundary for applying the conditional and disjunctive rules.
2
Apply the exclusive disjunction for mid-Holocene segments to sample AS-442.
Sample AS-442 must contain either basaltic cryptotephra OR high micro-meteoritic iridium, but cannot contain both.
The stimulus explicitly defines this mutual exclusivity for all mid-Holocene Amundsen-Scott segments.
3
Test the hypothetical assumption that sample AS-442 lacks basaltic cryptotephra.
If AS-442 lacks basaltic cryptotephra, it MUST have high iridium (by step 2) AND it MUST have been formed during non-explosive effusive volcanism (by the first premise, since it has a sulfate spike and no cryptotephra).
Evaluating the negation of the target condition reveals whether a logical contradiction arises.
4
Evaluate the result of step 3 against the third premise.
The third premise states that no segment with high iridium was formed during non-explosive effusive volcanism. This directly contradicts the outcome of step 3.
A valid deductive argument cannot result in mutually contradictory states.
5
Draw the necessary deductive conclusion by indirect proof (reductio ad absurdum).
Because assuming the absence of basaltic cryptotephra produces a direct contradiction, sample AS-442 must contain a basaltic cryptotephra deposit.
Eliminating one branch of a strict disjunction logically necessitates the truth of the other.

Anahtar Kavram

Deductive synthesis through conditional contraposition and proof by contradiction in exclusive disjunctions
Tahmini Süre:2m 0s
Bu soruyu puanla

Konular

Must Be True / Most Strongly Supported

Bu konudan daha fazla soru