Some cratons in Canada and Greenland shelter the oldest continental rocks in the world, about 4 billion years old. Other cratons in South Africa, Australia and Asia have continental rocks that are 3 billion years old. The oldest seafloor is comparatively very young, approximately 280 million years old.
Index fossils, intrustions and cross-cutting relationships.
Explanation:
The correct list of three different geologic features that help scientists determine the relative ages of rocks by their position is "index fossils, intrusions, and cross-cutting relationships".
