Monazite Geochronology

ThMaMonazite is a LREE – bearing orthophosphate mineral that can be used as a geochronometer.  Given its affinity for Th, it can be dated with non-isotopic techniques, like Electron probe microanalysis, at very high spatial resolution (ca. 1 micron). Due to monazite’s compositional variability, it responds to, and can thus monitor the growth and consumption of major and accessory phases during metamorphism, helping decipher complex and convoluted metamorphic histories in polydeformed terranes.

Age and origin of monazite symplectite, Adirondack Mountains

 

PROJECTS

Understanding the relationship between fluid evolution and monazite composition

Caka
intergrown monazite, allanite, and fluorapatite in an Iron-oxide Apatite (IOA) REE deposit in the eastern Adirondack Highlands

Using textural relationships to directly link geochronology to penetrative deformation

Regan et al., 2017a

Using in-situ U-Th-total Pb geochronology to date shear zones

Regan et al., 2014

 

Useful Links

UMass electron microprobe facility