Can anyone explain how the age of nematodes is confirmed to be 42,000 years from the age of deposits: The duration of natural cryopreservation of the nematodes

Can anyone explain how the age of nematodes is confirmed to be 42,000 years from the age of deposits: The duration of natural cryopreservation of the nematodes corresponds to the age of the deposits, 30000–40000 years.