How is the composition of uraninite varies through geological time?

Answer 1

Uraninite is a uranium-rich mineral with a composition that is largely UO2 (uranium dioxide), but which also contains UO3 and oxides of lead, thorium, and rare earths. All uraninite minerals contain a small amount of radium as a radioactive decay product of uranium. Helium was first discovered on Earth in uraninite after previously being discovered spectroscopically in the Sun's atmosphere. The extremely rare element technetium can be found in uraninite in very small quantities (about 0.2 ng/kg), produced by the spontaneous fission of uranium-238.

Uraninite is a major ore of uranium.

BY NOW U MUST HAVE NOTICED THAT URANINITE IS RADIOACTIVE ITSELF since it contains radioactive elements

Radioactive decay is the set of various processes by which unstable atomic nuclei emit subatomic particles (radiation). Decay is said to occur in the parent nucleus and produces a daughter nucleus. This is a random process, i.e. it is impossible to predict the decay of individual atoms.

A radioactive decay continues to occur the COMPOSITION OF URANINITE too, changes/varies through GEOLOGICAL TIME.