Approximately when did continents form?

Approximately when did continents form?

• A. 1.0 billion years ago
• B. 3.5 billion years ago
• C. 4.0 billion years ago
• D. 5.0 billion years ago

Answer: (B)

Continents form when buoyant continental crust becomes established and stable enough to persist over geological time. Evidence shows that by about three-and-a-half billion years ago, large, stable blocks of granitic, buoyant crust were already present, marking the emergence of recognizable continental landmasses during the Archean. Earlier times—around five billion years ago—were largely molten or undergoing intense differentiation, with no long-lived continents, and by around one billion years ago we’re already well into the Proterozoic after continents had largely begun to take shape. So, roughly three-and-a-half billion years ago is the best approximation for when continents formed.

Continents form when buoyant continental crust becomes established and stable enough to persist over geological time. Evidence shows that by about three-and-a-half billion years ago, large, stable blocks of granitic, buoyant crust were already present, marking the emergence of recognizable continental landmasses during the Archean. Earlier times—around five billion years ago—were largely molten or undergoing intense differentiation, with no long-lived continents, and by around one billion years ago we’re already well into the Proterozoic after continents had largely begun to take shape. So, roughly three-and-a-half billion years ago is the best approximation for when continents formed.