U-Th-Pb monazite dating and the timing of arc-continent collision in East Timor

作者：Berry R^*; Thompson J; Meffre S; Goemann K

来源：Australian Journal of Earth Sciences, 2016, 63(4): 367-377.

DOI：10.1080/08120099.2016.1217930

• Timor
• metamorphic age
• monazite
• Th-Pb age
• disequilibrium Th

The Timor Orogen represents one of the youngest arc-continent collisions exposed on the Earth. It has the potential to provide some of the key parameters about how this style of orogeny evolves. However, the metamorphic age of the highest-grade rocks formed in the collision remains controversial. Using U-Th-Pb dating of monazite from amphibolite-grade sillimanite and garnet-bearing schists we show the peak metamorphism occurred at 5.5-4.7 Ma. The young age of the monazite and the presence of significant amounts of common Pb required the development of a new protocol to simultaneously account for the Th-230 disequilibrium and the Pb-207 common Pb correction. The new estimate of metamorphic age is consistent with the estimates based on plate reconstructions for the initiation of arc-continent collision in East Timor. The metamorphic event is a result of this collision.

• 出版日期2016