TITLE:
Slope Year for the U-Pb Dating Method and Its Applications
AUTHORS:
Jie Yuan
KEYWORDS:
Slope Year, U-Pb Dating, Zircon, Mass Spectrum, Isotope, Initial Pb Isotope Concentration
JOURNAL NAME:
Open Journal of Geology,
Vol.5 No.5,
May
26,
2015
ABSTRACT: The slope year tslope for the U-Pb dating method is
given as , where λ238 and λ235 are the decay constants for 238U and 235U, respectively, and k is the slope of the tangent line at a
point on either the Concordia or Discordia line. These two lines are determined
by the initial 206(7)Pbi concentrations in minerals. If , the line is the Concordia. However,
if (∧is the logical operator “and”, also known as
the logical conjunction), or , the line is Discordia. The Concordia line is of
the form (where p stands for the present), while the
Discordia line has the form (where k and b are the slope and intercept of the
straight line, respectively).