SB 12.4.5
dvi-parārdhe tv atikrānte
brahmaṇaḥ parameṣṭhinaḥ
tadā prakṛtayaḥ sapta
kalpante pralayāya vai
brahmaṇaḥ parameṣṭhinaḥ
tadā prakṛtayaḥ sapta
kalpante pralayāya vai
Word for word:
dvi-parārdhe — two parārdhas; tu — and; atikrānte — when they have become completed; brahmaṇaḥ — of Lord Brahmā; parame-sthinaḥ — the most highly situated living entity; tadā — then; prakṛtayaḥ — the elements of nature; sapta — seven; kalpante — are subject; pralayāya — to destruction; vai — indeed.
Translation:
When the two halves of the lifetime of Lord Brahmā, the most elevated created being, are complete, the seven basic elements of creation are annihilated.