Resolving Cambrian, Carboniferous, Permian and Alpine monazite generations in the polymetamorphic basement of eastern Crete (Greece) by means of the electron microprobe
✍ Scribed by F. Finger; E. Krenn; G. Riegler; S. Romano; G. Zulauf
- Book ID
- 104463368
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 585 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0954-4879
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✦ Synopsis
The electron‐microprobe‐based investigation of accessory monazites in polished thin sections is a helpful tool in resolving the geochronology of a polymetamorphic basement. The method was applied to variably altered gneisses and micaschists from the retrogressed, originally amphibolite‐facies basement in eastern Crete (Greece). The presented data indicate that most monazite formed or recrystallized in response to high fluid activity during Alpine low‐temperature metamorphism. This low‐temperature monazite is characterized by distinctly low yttrium, uranium and thorium contents. However, older grains were able to survive in less retrogressed samples and have been traced with the electron microprobe, using microstructural and compositional criteria. In‐situ chemical Th–U–Pb dating of these pre‐Alpine monazites provides evidence for an igneous event in the Cambrian, and two different metamorphic events in the Carboniferous and Permian.