Question

In 1864, Scottish polymath James Croll proposed that glacial epochs were triggered by periodic variations in Earth’s orbital eccentricity, which altered the distribution of solar radiation. Unlike earlier qualitative hypotheses that attributed glaciation solely to shifting ocean currents or topographic shifts, Croll attempted a rigorous quantitative mechanism, calculating how eccentricity-driven winters in aphelion would amplify albedo feedbacks through ice accumulation. However, Croll’s model predicted that glacial periods should alternate asynchronously between the Northern and Southern Hemispheres and that the most recent glacial epoch ended roughly 80,000 years ago. While nineteenth-century geologists initially welcomed Croll’s physical framework for establishing an absolute geological chronology, stratigraphers studying post-glacial erosion rates and Niagara Falls recession soon argued that the last ice sheet retreated far more recently—likely between 10,000 and 15,000 years ago. Furthermore, field evidence from transatlantic fossil floras suggested synchronous interhemispheric cooling rather than hemispheric alternation. Consequently, despite Croll’s pioneering integration of celestial mechanics with terrestrial feedback loops, late-nineteenth-century consensus sidelined his timeline, preferring empirical stratigraphic estimates until Milutin Milankovitch later refined the orbital parameters in the 1920s.

Consider each of the three choices separately and select all that apply.

Which of the following can be inferred from the passage regarding nineteenth-century geologists’ reaction to Croll’s theory?