Question

3. In Excel or a comparable program, construct a concordia curve. This can be done by making a table of ages spanning the history of the Earth (O Ma to 4570 Ma) along with corresponding 206 Pb/238U values (for y axis) and 207Pb/23SU values (for x axis).
is there some type of equation or formula in excel to help we with this?

Answer 1

U-Pb Concordia diagram: On a plot of 206Pb*/238U vs. 207Pb*/235U, the locus of all points yielding concordant
dates is called the concordia curve.
Samples experiencing no Pb or U mobility move along
the concordia as they age. Samples that do not plot on the concordia yield discordant dates.
The concordia curve bends over because 235U decays
much faster than 238U; this causes 207Pb to be produced faster than 206Pb.

Since where lemda is decay constant and 't' is geological time.

238 U ( 9 Pun") = (eiur – 1) (20?*) = (2+z34 – 1) 235 U

With these equations we can find values of ratios corresponding to geological time.

Concordia diagram is given by:

Alignment Number Styles pan 2 07Pb/2350 206Pb/2320 91.7 75.2 54.96 63.2G 7 3.5 Ga 63.5 50.4 41.2 33.6 1.04 0.97 0.92 0.86 0.8 0.74 0.69 0.64 21.5 93.2 Ga 10 3.0 GA 224 0.59 0.54 12 2.6G 206Pb/238U 13 2.4 Ga 142.2 Ga 15 2.0 Ga 16 1.8 Ga 17 1.6 Ga 18 1.4 Ga 19 1.2 Ga 0.49 0.45 0.4 0.36 0.32 0.28 0.24 0.2 0.16 0.13 0.09 0.06 0.03 20 LOG a. S S 0.8 0 10 20 30 70 80 90 0.6 Ga 100 40 50 60 207Pb/235U 0.2 230.4 Ga 24 0.2 Ga 25 0.0 Ga * Sheet1 Peady Sheet2 Sheet3 Average: 1048125 C ount: 75 su 5031
or
Chart Type Template Rowolumn Data Chart 1 Chart Styles 1 Time Span 207Pb/2354 206Pb/2380 Chart Title 91.7 75.2 63.5 50.4 41.2 33.6 27.5 22.4 18.2 14.7 11.9 917,104 75 2,097 65,092 1.04 0.97 0.92 0.86 0.8 0.74 0.69 0.64 0.59 0.54 0.49 0.45 0.4 0.36 0.32 0.28 0.24 0.2 0.16 0.13 0.09 0.06 0.03 Axis Title 3 4.4 Ga 4.2 Ga 5 4.0 G 6 3.8 G 7 3.6 Ga 8 3.4 Ga 9 3.2 Ga 10 3.0 Ga 11 2.8 Ga 12 2.6 Ga 13 2.4 Ga 14 2.2 Ga 15 2.0 Ga 16 1.8 Ga 17 1.6 Ga 18 1.4 Ga 19 1.2 Ga 20 1.0 Ga 21 0.8 Ga 22 0.6 Ga 23 0.4 Ga 24 0.2 Ga 25 0.0 Ga * Sheet1 Ready 50.4, 0.86 412.0.8 33.6, 0.74 27.5, 0.69 22.4,064 18.2, 0.59 14.7, 054 11.9, 0.49 960.45 77.00 6.2.0.36 495 32 38.0.28 29, 0.24 23,02 Series Series 0. 2 12,819 0 10 20 30 40 50 Axis Title 60 70 80 90 100 Sheet2 Sheet3 Average: 10.48125 Count: 75 Sum 503.1