See the link below for radioactive decay chains.
The end products of uranium isotopes decay chain are the isotopes of lead.
Isotopes of lead are the final products of the decay chain of uranium.
Isotopes of lead
Ultimately lead, as it is the only element in the uranium decay chains with isotopes that are stable. Specifically the isotopes 206, 207, and 208; each of which is the end of a different decay chain.
It is not yet discovered since all of the uranium isotopes are having half life for several millions of years. We would be able to find it after atleast 700 millions of years.
The cause is the radioactive decay of uranium isotopes.
There are 3 naturally occurring isotopes of Uranium, all decay by alpha to Thorium:238U --> 234Th + 4He235U --> 231Th + 4He234U --> 230Th + 4He
Isotopes of radon (Rn)
Plutonium is not related to uranium isotopes radioactive decay; plutonium is obtained by nuclear reactions from uranium isotopes only in nuclear reactors.
Thorium, radium, radon, polonium, thallium, etc.
20 isotopes
All the isotopes from the decay chains exist in these rocks. The most important are the dangerous isotopes of radium and radon.