Where are the world's oldest mountains?

Answer 1

The Barberton Greenstone Belt in South Africa is estimated at 3.4-3.6 billion years old, and generally regarded as the world's oldest mountains. Their age is indisputedly older than anything in North America (the Appalachians / Blach Hills / Porcupines / Smokies etc) and only Western Australia lays a possible claim. Most geologists accept the Greenstone Belt as being the oldest range on Earth. Some people attempt to dispute the Belt's title by arguing that they are not especially tall mountains. This is a rather absurd attempt. Though they are not especially tall, they are roughly 1000 feet taller than anything in the UK (the Scottish Highlands), taller than the Adirondacks, and at over a mile in height they rise over 4000 feet from the surrounding lowlands. The usual official definition of a mountain ranges from 1000 feet (US) to 2000 feet (UK) - and by all of these this is indisputedly a substantial range. Not tall by world standards - but easily a mountain range. Fossils indicate Bacterial life older than 3 Billion years old in the Range, Gold formed ca 3 Billion years ago, and the range showcases a more complete picture of Earth's geological history than any other Mountain range (indeed many would argue any other region) on Earth.