Radiogenic nuclide
Radiogenic nuclides used in geology

Parent nuclide
Daughter nuclide
Decay constant (yr−1)
Half-life
190Pt
186Os
1.477 ×10−12
469.3 Gyr *
147Sm
143Nd
6.54 ×10−12
106 Gyr
87Rb
87Sr
1.402 ×10−11
49.44 Gyr
187Re
187Os
1.666 ×10−11
41.6 Gyr
176Lu
176Hf
1.867 ×10−11
37.1 Gyr
232Th
208Pb**
4.9475 ×10−11
14.01 Gyr
40K
40Ar
5.81 ×10−11
11.93 Gyr
238U
206Pb**
1.55125 ×10−10
4.468 Gyr
40K
40Ca
4.962 ×10−10
1.397 Gyr
235U
207Pb**
9.8485 ×10−10
0.7038 Gyr
129I
129Xe
4.3 ×10−8
16 Myr
10Be
10B
4.6 ×10−7
1.5 Myr
26Al
26Mg
9.9 ×10−7
0.7 Myr
36Cl
36Ar/S
2.24 ×10−6
310 kyr
234U
230Th
2.826 ×10−6
245.25 kyr
230Th
226Ra
9.1577 ×10−6
75.69 kyr
231Pa
227Ac
2.116 ×10−5
32.76 kyr
14C
14N
1.2097 ×10−4
5730 yr
226Ra
222Rn
4.33 ×10−4
1600 yr

Question: How are 206Pb, 207PB and 208PB formed?
Answer: The ²⁰⁶Pb is formed from ²³⁸U, ²⁰⁷Pb from ²³⁵U and ²⁰⁸Pb from ²³²Th.