Geochemist: Some volcanologists argue that the sudden spike in atmospheric sulfur dioxide recorded in ancient subpolar ice cores was caused by the eruption of Mount Hekla around 1100 BCE, pointing out that tephra layers in adjacent peat deposits date to roughly that era. However, this conclusion is premature. Cryogenic analysis shows that the sulfur particles in the ice core exhibit a distinctive mass-independent fractionated isotopic signature that forms exclusively in the upper stratosphere. Mount Hekla's plume height during that period was insufficient to inject gases into the stratosphere, which indicates that the ice-core sulfur must have originated from an equatorial volcano with far greater explosive power.
Which of the following most accurately describes the method of reasoning employed by the geochemist?
- challenging a causal claim by presenting physical evidence that the phenomenon in question required conditions the purported cause could not have generatedCevap
- Brejecting a causal hypothesis on the grounds that the evidence offered in its favor relies on inaccurate dating of adjacent deposits
- Ctreating a finding that provides indirect support for an alternative origin as conclusive proof that no regional volcanic activity occurred
- Dinferring that because stratospheric injection requires powerful eruptions, any absence of high-altitude sulfur rules out past volcanic eruptions
- Eattempting to refute an empirical hypothesis by arguing that a general geochemical law has exceptions in subpolar environments