isochrons

Noun

isochron (plural isochrons)

1. (geochemistry) A line on a chart linking rock of the same age (as determined from isotope ratios).
   • Recapitulating, any suite of comagmatic rocks with an age t defines an isochron if its members all had the same initial ^{₈₇}Sr/^{₈₆}Sr ratio and if it was closed to both Rb and Sr since crystallization occurred and neither element was introduced from any extraneous source.[…]In this way...1997, H.-G. Attendorn, R. Bowen, Radioactive and Stable Isotope Geology, Chapman & Hall, page 163
2. (dynamical systems) A collection of points (such as a manifold), each point representing a set of initial conditions for a given dynamical system, such that every set results in the same long-term behaviour of the system.
   • The entire plane is foliated by isochrons.2007, Eugene M. Izhikevich, Dynamical Systems in Neuroscience, The MIT Press, page 446