The primordial salt water of the Enuma Elish, personified as the mother of the first gods and killed by Marduk, who splits her body and makes the sky from one half and the earth from the other.
The Sitchin reading
Zecharia Sitchin takes the epic as a cosmogony rather than a theogony: Tiamat is a planet that once orbited beyond Mars, and the satellites of the invading body strike her, carrying her upper half into a new orbit as Earth and leaving her lower half as the asteroid belt, the “hammered bracelet” of Genesis. Her chief satellite Kingu becomes the Moon. He is careful on one point that most retellings drop, that the two planets did not collide: it was the satellites that struck.
What the arithmetic says
The site’s Tiamat bench runs the collision. The obstacle is mass: the asteroid belt totals roughly four ten-thousandths of an Earth mass, about three percent of the Moon, which is difficult to reconcile with the remains of a body several times the size of Earth. The giant-impact model of lunar formation does involve a planetary collision and is sometimes offered as vindication, but it produces the Earth-Moon system by a route the epic reading does not describe.
Connections
Enuma Elish · Marduk · Nibiru · Zecharia Sitchin · The Anunnaki Chronicles · Planet Nine · Anunnaki · Cylinder Seal VA 243