Overlapping in Time – How Strategic, How Age Strict?

The W76/MK4 TRIDENT deployed Reentry Body comprising the bulk of the Nation's Strategic Deterrent is now reaching its original design life, according to John Pike at GlobalSecurity.org . Manufactured between 1972 and 1987, continued deterrent value requires extended deployment beyond original, 20-year service life.

The W74/2-36 DETRITAL ZIRCON crystals (zirconium silicate) are nearly indestructible and preserve, in chemical form, information about the environments which created them. Dr. John Valley of the UW Geology Department is currently studying the world's oldest known terrestrial material (4.4-billion-years-old zircons) from Jack Hills, Western Australia.

You be the judge, if you dare burn the cells.