Chalk layers in Champagne reflect sedimentation dating back to when the Paris Basin was an inland sea. This indicates chalk formed in a former what?

• A. Desert.
• B. Forest.
• C. Sea.
• D. Mountain.

Answer: (C)

Chalk is a marine sedimentary rock formed from the calcareous remains of microscopic marine organisms that settle to the seafloor. The Champagne chalk indicates deposition occurred while the Paris Basin was covered by an inland sea during the Late Cretaceous, so the chalk formed in a former sea environment. Deserts, forests, or mountains don’t produce chalk; deserts yield sands and evaporites, forests leave coal-like deposits, and mountains tend to yield non-marine or metamorphic rocks.