This is something interesting that I just found online.
Question
When was the story of Noah's Ark written?
Answer
The biblical story of Noah's Ark actually has two, slightly different stories woven together to appear to be one complex and slightly confusing story. The first of these was written by the Yahwist source, who lived around 800-900 BCE, while the second story was written by the Priestly source, who probably lived during the sixth century BCE*.
The stories of Noah's Ark have much in common with the story of the great flood in the much older Epic of Gilgamesh, as well as several other Near Eastern epics. However, it was probably not a copy of the Epic of Gilgamesh, but rather they probably had a more ancient common source, written long before the time of the Hebrew people. Ian Wilson (Before the Flood) believes that there once was a great flood that to its survivors must have seemed like a world-wide event sent by the gods. This occurred in 5600 BCE, when the Mediterranean Sea broke through the narrow Bosporus land-bridge and inundated the lush farmland where the Black Sea now lies. Epic stories of this event and its survivors would have been passed on orally until the development of writing at least one thousand years later, when the legend predecessor to Noah's Ark was committed to writing.
Footnote
* The verses attributed to the Yahwist are: Genesis 6:5-8, 7:1-5, 7:7, 7:10, 7:12, 7:16b-17, 7:22-23, 8:2b-3a, 8:6, 8:8-12, 8:13b, 8:20-22. The verses attributed to the Priestly author are: Genesis 6:9-22, 7:6, 7:8-9, 7:11, 7:13-16a, 7:18-21, 7:24, 8:1-2a, 8:3b-5, 8:7, 8:13a, 8:14-19, 9:1-17.