I have read that (according to Shiva Purana) Sati's body was turned into ashes.
6-7. She desired to cast-off her body due to her anger with Dakṣa. She desired to burn off the body and retain the pure wind by yogic means. In this posture she remembered the feet of her lord and nothing else.
- Her body divested of its sins fell in the yogic fire and was reduced to ashes, O excellent sage, in accordance with her own wish.
Source; Chapter 30 - Satī’s casting off of her body and the subsequent disorder
If that is true, how did Shaktipeethas come into existence?
I'm little bit confused about it.