Separation of heaven and earth
The separation of heaven and earth is a cross-cultural creation myth event. The separation serves the role of differentiating the chaotic, undifferentiated cosmos (sometimes interpreted as a universal cosmic ocean) into coherent and organized parts.
The mechanics and cause differ from one story to another, but is usually either a spontaneous process, or a result of the agency of a deity. In ancient Near Eastern texts, the original mass that is separated is a solid in older Sumerian literature, but becomes a water in younger Akkadian literature (such as the Enuma Elish). Sumerian literature mentions the separation event most frequently than any other.