During Quaternary glacial-interglacial cycles, global sea-level fluctuations profoundly altered continental margins. What primary global process drove the episodic drowning of river valleys and subsequent formation of estuarine backwaters along the west coast of India?

💡 Solution & Explanation

Eustatic sea-level fluctuations driven by the growth and melting of continental ice sheets during Quaternary glacial and interglacial periods caused marine transgressions and regressions, flooding coastal valleys to form the backwaters and estuaries seen today. Regional tectonic subsidence and volcanic action did not drive these worldwide coastal geomorphological changes. Eustatic changes represent global sea-level variations independent of local vertical land movements.