Columnar basalt formations, characterized by hexagonal stone pillars, are created through a distinct geological cooling process. When a thick layer of basaltic lava begins to cool, it contracts and solidifies. This contraction causes fractures to form on the cooling surface. As the cooling front propagates downward into the lava flow, these fractures extend vertically, splitting the rock into neat geometric columns. The Giant's Causeway in Northern Ireland is a classic example of this phenomenon, showcasing how uniform thermal contraction produces regular patterns over vast basaltic landscapes.
Which choice best describes the overall structure of the text?
- It introduces a geological phenomenon, details the physical process behind its formation, and provides a specific real-world example of the phenomenon.Answer
- BIt outlines a geological problem, proposes a theoretical solution to prevent it, and evaluates the effectiveness of that solution.
- CIt presents a scientific theory, disputes the theory with new geological evidence, and offers an alternative hypothesis.
- DIt describes a specific geographic location, traces its historical development, and advocates for its preservation.
Answer
It introduces a geological phenomenon, details the physical process behind its formation, and provides a specific real-world example of the phenomenon.
The correct option accurately traces the progression of the text: it starts by introducing the geological phenomenon of columnar basalt formations, follows with a step-by-step description of the cooling and contraction process that creates them, and ends by citing the Giant's Causeway as a specific example.
Step-by-Step Solution
Key Concept
Overall Text Structure Analysis