Rb-Sr data structure - a possible cause for differences in Rb-Sr whole-rock and U-Pb zircon ages

Differences between U-Pb zircon and Rb-Sr whole-rock ages are often interpreted to be due to later geologic disturbances such as low-grade metamorphism and slow cooling. Yet, apparently contrasting ages can also be due to erroneous ages derived from non-ideal systems. Their incorporation into geological models results in distorted time scales and may ultimately lead to the suggestion of geologic processes and events that are not real. I illustrate this point discussing the geochronologic database that originally was used (1) to constrain the evolution of silicic crust in the Svecofennian area, (2) to define the geographic extent of the Sveconorwegian-Grenville orogeny in north Norway and east Greenland, (3) to determine the age of thrusting in the southern Swedish Caledonides, and (4) to confine the Apparent Polar Wander Path (APWP) of the Baltic Shield.