The branch of geology that deals with the arrangement of sedimentary layers and their relative ages is called?

• A. Adhesion
• B. Aphotic Zone
• C. Stratigraphy
• D. Silt

Answer: (C)

Stratigraphy is the study of layered rocks and how they are arranged in time. It focuses on the sequence of sedimentary layers and uses their positions to infer relative ages—how one layer is younger or older than another. In practice, geologists apply principles like the law of superposition (younger layers sit atop older ones), original horizontality (layers were deposited roughly flat), lateral continuity (layers extend until they thin out or encounter an obstacle), and fossil succession to correlate layers across regions and reconstruct past environments. This branch helps us read Earth’s history from the stacked record of sediments. The other terms refer to different ideas: adhesion is a surface force, the aphotic zone is a deep-dark marine zone, and silt is a type of fine sediment, not a field of study.