Tectonics – Mountain Building After Continental Drift Mountains that came into being after continental drift began and the supercontinent broke up are classified primarily as:

Introduction / Context:
Earth’s mountain systems are often categorized by age and origin. Following the initiation of continental drift and breakup of ancient supercontinents, several major orogenies created what are commonly termed “young” mountains relative to ancient shields and eroded ranges. This question asks for the best broad classification.

Given Data / Assumptions:

• After supercontinent breakup, collisional and convergent processes built new ranges.
• Examples: Himalayas, Alps, Andes are considered geologically young compared to the Aravallis or Appalachians (older, more denuded segments).
• We are choosing a general age-based classification, not a detailed genetic subtype.

Concept / Approach:
“Young mountains” is the umbrella term typically used for post-breakup orogens that are high, rugged, and tectonically active. While many of them are also “fold mountains” by process (compression and folding), the stem emphasizes timing (“after the breakup”), so age-based labeling is the most direct answer. Hence, “young mountains” fits the intent best.

Step-by-Step Solution:

Verification / Alternative check:
Global examples (Himalayas, Alps) are conventionally taught as young fold mountains; calling them “young mountains” aligns with school-level categorization tied to post-Pangaea tectonics.

Why Other Options Are Wrong:

• Old mountains: Refer to much older, highly eroded systems (e.g., Aravallis).
• Volcanic mountains: A genetic type; not all post-breakup mountains are volcanic.
• Fold mountains: True for many, but the question emphasizes timing; the standard textbook answer highlights youth.

Common Pitfalls:
Over-focusing on process (folding) when the stem cues time (“after the continental drift started”). In many exams, the keyed response is the age descriptor.

Final Answer:
young mountains