The Great Goddess appears to have been a universal phenomenon
Early humans saw that every spring plants seemed to be born only to mature and die. Similarly, they saw that herds seemed to replenish. As they could see that plants grew from the earth, they extrapolated that animals must as well. They personified the earth as a woman. Like the human woman they could see, she spontaneously became pregnant and gave birth to the various life forms humans came across.
Not much is known about any specific practices, and likely they varied across the world. However, there have been many sculptures of women possessing oversized breasts and butts found all over Eurasia. Likely these were visual reminders of the Great Goddess.
There is a mother goddess in nearly every religion on Earth, most of them spontaneously generated the first generation of sentient life.