Final answer:
The approximate age of the Appalachian Mountains is 300 million years or 300 Ma. The mountains were formed during the Paleozoic era through multiple collisions with small island chains and the supercontinent of Gondwana. The abbreviation Ma stands for millions of years ago.
Step-by-step explanation:
The approximate age of the Appalachian Mountains is 300 million years or 300 Ma.
The mountains were formed during the Paleozoic era through multiple collisions with small island chains and the supercontinent of Gondwana. The Valley and Ridge Province, which forms the center of the Appalachian Mountains, is composed of highly folded and faulted sedimentary rock from the Paleozoic era, including the Devonian and Cambrian periods. The Blue Ridge Province, to the east of the Valley and Ridge, consists of much older igneous and metamorphic rock that was formed during the Proterozoic era and later deformed during the Middle Paleozoic era.
The age of the Appalachian Mountains is estimated using the abbreviation Ma, which stands for millions of years ago.