Determining the absolute oldest mountain range on Earth is tricky, as mountains are constantly being formed and eroded. However, there are a few contenders for the title of oldest surviving mountain range:

* The Barberton Greenstone Belt in South Africa: This range, with its oldest rocks dating back to 3.6 billion years old, is often considered the oldest. However, it's not a classic mountain range with high peaks, but rather a region of highly deformed and metamorphosed rocks.

* The Nuvvuagittuq Greenstone Belt in Canada: This belt, with rocks up to 4.28 billion years old, is even older than the Barberton Greenstone Belt. However, its status as a true mountain range is disputed, as it may have formed through a different process.

* The Canadian Shield: This vast region of ancient rocks, dating back to 3.96 billion years old, may have once contained towering mountains, though they have long been eroded.

Ultimately, it's difficult to definitively claim one specific range as the "oldest". While the Barberton Greenstone Belt is often cited, all of these ancient formations offer glimpses into the Earth's very early history.