Question

The _______ era encompasses 90 percent of Earth's history. Some of the oldest rocks ever discovered on Earth were found in western Greenland and were dated at approximately _______ billion years using isotopic dating methods.

Answer 1

The Pre-Cambrian era spans 90 percent of Earth's history, and isotopic dating places some of the oldest rocks in Greenland at 3.96 billion years. The Earth's age is between 4.4 and 4.57 billion years.

Step-by-step explanation:

The Pre-Cambrian era encompasses 90 percent of Earth's history, which includes the Hadean, Archean, and Proterozoic eons. Some of the oldest rocks ever discovered on Earth were found in western Greenland and were dated at approximately 3.96 billion years using isotopic dating methods, such as uranium-lead dating. Moreover, other ancient rocks and minerals, like the Jack Hills zircons from Australia, have been dated to be almost 4.4 billion years old. These findings are part of the evidence used to estimate the age of Earth to be between 4.4 and 4.57 billion years, with 4.57 billion years representing the age of the solar system and thus the maximum age of Earth.