| Should a point plot below the line, it could indicate that a particular sample was open to migration of the dating elements or that the sample was contaminated and lay below the isochron when the rock solidified. |
| The emplacement of the collision-type Halatu granites took place at ca. 230 Ma based on whole rock, Rb-Sr isochron and zircon Pb evaporation analyses. |
| Isochron dating has been developed in an attempt to solve such problems. |
| However, isochron dating bears faulty assumptions of its own. |
| New zircon U-Pb and Rb-Sr mineral isochron ages, together with previously published results, indicate that these granites were emplaced in Late Palaeozoic to Late Mesozoic times. |
| Within the context of Kirchhoff migration, this stretch is associated to the variation in the curvature of isochron surfaces for different times on an input seismic trace. |
