Uranium-Lead, Metamorphic Rocks

Abstract

Definition: The word metamorphism derives from the Greek word "metamorphosis," meaning change of form. Metamorphism is the process by which the mineralogy of rocks is changed as the result of pressure and temperature according to their composition and with the aid of fluid and deformation. Metamorphism is mainly concerned with the changes that take place when rocks are in the solid state, even though melt can be one of the phases present.

Dating Strike‐Slip Ductile Shear Through Combined Zircon‐, Titanite‐ and Apatite U–Pb Geochronology Along the Southern Tan‐Lu Fault Zone, East China

“…This is especially true given the potential of the K‐Ar ( 40 Ar/ 39 Ar) system in mica to be perturbed by post‐kinematic, ephemeral tectono‐thermal events (Hacker & Wang, 1995; Ratschbacher et al., 2000). The U–Pb system, in contrast, is relatively stable under medium‐ to low‐grade metamorphic conditions for most minerals (R. Parrish, 2014; Rubatto, 2013; Yakymchuk et al., 2017). In this regard, the U–Pb geochronology of monazite, titanite, apatite and rutile may be more effective than the 40 Ar/ 39 Ar systems for dating shear deformation under amphibolite‐ to greenschist‐facies metamorphic conditions (Chew & Spikings, 2015; Kohn, 2017; R. R. Parrish, 1990; Zack & Kooijman, 2017), especially when fluid mediated (re)crystallization occurs (e.g., Ribeiro et al., 2020).…”