Question

The picture shows a type of rock called a banded iron formation. The rock contains high levels of iron oxides minerals, which form only when iron at Earth's surface combines with oxygen. Approximately how old would Earth's oldest banded iron formations be?

Answer 1

the answer is 3 billion years ago

Answer 2

Banded iron formation, or also referred to as BIF, is unique sedimentary rock of biochemical origin. Unique because of their unique make up, unique age and unique origins. These rocks are very old.

BIF date to as old as 3 billion years old, but most are aged at around 2.5 billion and some are as "young" as 1.8 billion. So, the Earth's oldest banded iron formation is 3 billion years old.