Journal article
The Triassic age for oceanic eclogites in the Dabie orogen: Entrainment of oceanic fragments in the continental subduction
Lithos, Vol.117(1), pp.82-98
2010
Handle:
https://hdl.handle.net/2376/114327
Abstract
Low-temperature and high-pressure eclogites with an oceanic affinity in the western part of the Dabie orogen have been investigated with combined Lu–Hf and U–Pb geochronology. These eclogites formed over a range of temperatures (482–565
°C and 1.9–2.2
GPa). Three eclogites, which were sampled from the Gaoqiao country, yielded Lu–Hf ages of 240.7
±
1.2
Ma, 243.3
±
4.1
Ma and 238.3
±
1.2
Ma, with a corresponding lower-intercept U–Pb zircon age of 232
±
26
Ma. Despite the well-preserved prograde major- and trace-element zoning in garnets, these Lu–Hf ages mostly reflect the high-pressure eclogite-facies metamorphism instead of representing the early phase of garnet growth due to the occurrence of omphacite inclusions from core to rim and the shell effect. An upper-intercept zircon U–Pb age of 765
±
24
Ma is defined for the Gaoqiao eclogite, which is consistent with the weighted-mean age of 768
±
21
Ma for the country gneiss. However, the gneiss has not been subjected to successive high-pressure metamorphism. The new Triassic ages are likely an estimate of the involvement of oceanic fragments in the continental subduction.
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Details
- Title
- The Triassic age for oceanic eclogites in the Dabie orogen: Entrainment of oceanic fragments in the continental subduction
- Creators
- Hao Cheng - State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, ChinaS. Andrew DuFrane - School of Earth and Environmental Sciences, Washington State University, Pullman, Washington 99164, USAJeffrey D Vervoort - School of Earth and Environmental Sciences, Washington State University, Pullman, Washington 99164, USAEizo Nakamura - Institute for Study of the Earth's Interior, Okayama University at Misasa, Tottori 682-0193, JapanQiuli Li - State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, ChinaZuyi Zhou - State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China
- Publication Details
- Lithos, Vol.117(1), pp.82-98
- Academic Unit
- Environment, School of the (CAS)
- Publisher
- Elsevier B.V
- Identifiers
- 99900548042501842
- Language
- English
- Resource Type
- Journal article