Matsya Purana — Śrāddha Procedure: Types
कन्याकुम्भवृषस्थे ऽर्के कृष्णपक्षेषु सर्वदा यत्र यत्र प्रदातव्यं सपिण्डीकरणात् परम् तत्रानेन विधानेन देयम् अग्निमता सदा //
kanyākumbhavṛṣasthe 'rke kṛṣṇapakṣeṣu sarvadā yatra yatra pradātavyaṃ sapiṇḍīkaraṇāt param tatrānena vidhānena deyam agnimatā sadā //
Whenever the Sun is in Virgo, Aquarius, or Taurus, and always during the dark fortnight (kṛṣṇa-pakṣa), whatever offering is to be made after the rite of sapiṇḍīkaraṇa (joining the departed to the ancestral line) should invariably be given according to this prescribed procedure—by one who maintains the sacred fire.
It does not address pralaya; it focuses on dharma—specifically the calendrical timing and correct procedure for ancestor offerings after sapiṇḍīkaraṇa.
It primarily guides the householder (gṛhastha), especially one who maintains the sacred fires, to perform post-sapiṇḍīkaraṇa śrāddha/offerings in the proper season (Sun in specified signs) and in the kṛṣṇa-pakṣa, emphasizing disciplined ritual duty.
Ritual significance: it prescribes auspicious/required timing (solar sign + dark fortnight) and insists the offering be made by an agnimān (one maintaining sacred fire) according to an established vidhi (procedure).