Creation Myths of The Aborigine and Navajo

In the Aborigine creation myth, all was dark. The sun, moon, and
stars slept behind the Earth in eternal darkness. One day the ancestors—or Ungambikula—decided to awake from their eternal sleep and set forth around the land. They found half created humans, some half animal half human, others half human half plant. This was not a good thing for the ancestors, so they carved out legs, bodies, arms, and faces with their great stone knives, and thus the first humans were created. After completing their final touches on all humans, many of the ancestors slipped back into the ‘Eternal Dreamtime’, while others turned into a tree, a rock, or a waterhole, for the people to remember where they came from. 

            As you can see from the above descriptions, both cultures are very diverse in relation to their own beliefs; however they are also very much alike.  Both stories contain a figure, or deity forming the humans into what we see them as today, in the Aborigine myth the ancestors formed the first humans, similar to Navajo legend of human creation through the use of a magical reed.  Additionally, even though an evil being is not part of aborigine myth, I am quite sure some sort of evil being plays a prominent role in shapeless beings all around.

Both of these cultures started during different times in history, yet they still have similar backgrounds when it comes to their creation myths, and beliefs. One could be led to believe that since these two cultures were very similar; could it be possible that all cultures derived from one individual myth?  No one may ever know for certain, however after completing three-months of study relating to creation myths I believe it is a plausible scenario.