Prior to Louis Agassiz’s presentation of glacial theory in 1837, nineteenth-century geologists overwhelmingly attributed the presence of erratic boulders in non-alpine Europe to catastrophic marine deluges. Proponents of diluvialism posited that immense torrents swept over continents, depositing displaced debris far from its bedrock origin. Agassiz, however, observed that fine striations on Northern European bedrock lacked the irregular gouging characteristic of waterborne gravel; instead, their parallel alignment mirrored micro-topographical scars left by contemporary alpine glaciers. Opponents countered that ice masses could not have reached low-altitude regions without leaving evidence of continuous ice bridges connecting mountain chains to plains. In response, Agassiz highlighted erratic boulders resting atop fragile, uncompressed sedimentary layers. Such delicate strata would have been scoured away by sustained continental ice movement, implying that boulder dispersal occurred during rapid, episodic glacial advances rather than beneath an unbroken, permanent ice sheet.
Which of the following can be inferred from the passage regarding nineteenth-century opponents of the glacial theory?
- AThey argued that fine parallel striations on bedrock were produced primarily by catastrophic marine deluges.
- BThey demonstrated that fragile sedimentary strata could withstand prolonged exposure to continental ice movement.
- They assumed that glacial expansion into low-lying areas would require unbroken physical connections to mountain glaciers.Cevap
- DThey acknowledged that erratic boulders were deposited during rapid, episodic climatic events.
- EThey dismissed diluvialism because it failed to account for the alignment of bedrock gouges.