Which of the following gases is not considered a major greenhouse gas in the Earth's atmosphere?

Greenhouse gases are those that can absorb and emit heat and radiation, contributing to the greenhouse effect and global warming. 

The major greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. 

Therefore, Calcium carbonate is not a major greenhouse gas. The other options, namely carbon dioxide, methane, and water vapor, are all significant contributors to the greenhouse effect.