Markandeyapurana 46.39

46.39

bhūrloko 'tha bhuvarlokaḥ svarlokaśca vināśinaḥ /
tathā vināśamāyānti maharlokaśca tiṣṭhati //

The Bhūrloka, the Bhuvarloka and the Svarloka are perishable and pass[11] to dissolution; and the Maharloka stands, yet the dwellers therein by reason of the heat go to the Janaloka. And Brahmā sleeps indeed during the night in the three worlds which have been dissolved into one ocean. That night is of exactly the same duration. At its termination creation begins again. And so passes one of Brahmā's years, and a hundred years is the whole. For a hundred of his years is denominated a Para; and a Parārdha or half a Para is well-known to be composed of fifty years. So then a Parārdha of his life has elapsed, O brahman; at the close of which occurred the Mahākalpa, which is famed as the Pādma. Of the second Parārdha which is now passing, O brahman, the first kalpa (or cycle) ordained is this one called the Yārāha.