Atomica: Discordia

: For accurate results, "common lead" (lead not produced by radioactive decay inside the mineral) must be correctly subtracted. High-precision tools like SHRIMP (Sensitive High-Resolution Ion Microprobe) are often used to refine these 3D planar regressions .

: Scientists use mathematical approaches like the "York" or "Ludwig" methods to perform a linear regression of measurements to define the Discordia line. Discordia atomica

: This point often corresponds to the age of a later metamorphic event or disturbance that caused the lead loss. Interpretation Guidelines : For accurate results, "common lead" (lead not

: This point typically represents the original age of crystallization for the minerals. It indicates when the isotopic clock first started ticking. : This point often corresponds to the age

In the context of geochronology and U-Pb (Uranium-Lead) radioisotope dating, refers to a straight line on a Concordia diagram that represents a suite of minerals that have lost some of their daughter isotopes (lead) or parent isotopes (uranium) due to a geological event.