A combined study of detailed petrographic observation, mineral chemistry analysis and phase equilibrium modeling indicates that the high-temperature eclogites from the Dabie orogen, central China, experienced two episodes of anatexis: the first is phengite dehydration melting during the exhumation of deeply subducted slices, and the second is heating melting related to the post-orogenic collapse. Petrographic evidence and clues of the anatectic events include biotite + plagioclase + garnet ± amphibole intergrowth in matrix and biotite + plagioclase intergrowth within amphibole porphyroblast. Pressure–temperature (P–T) pseudosection and modal variation diagram indicate that the biotite + plagioclase + garnet ± amphibole in matrix was formed by the reactions phengite + clinopyroxene + quartz = melt + sanidine + garnet + plagioclase and later melt + sanidine + garnet = biotite + plagioclase, while the biotite + plagioclase intergrowths within poikiloblastic amphibole were formed by the reaction amphibole + muscovite + epidote = biotite + plagioclase + melt. In addition, the combination of petrological observations and P–T estimates suggests that the first melting event occurred at the late Triassic, while the second is related to the early Cretaceous mountain-root removal and subsequent asthenospheric upwelling and heat input. As the P–T paths of high-temperature/ultrahigh-pressure rocks have high probabilities to cross-cut phengite-melting curves, phengite melting during decompression may be a common process in these rocks. Moreover, the coexistence of multiple episodes of anatexis in a single tectonic slice suggests caution when identifying and dating partial melting in high-temperature/(ultra)high-pressure rocks.
Skip Nav Destination
Article navigation
Research Article|
September 01, 2019
Anatexis of high-T eclogites in the Dabie orogen triggered by exhumation and post-orogenic collapse
Liang-Peng Deng;
1
CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China
, Hefei230026, China
2
School of Earth Science, East China University of Technology
, Nanchang330013, China
Corresponding authors, e-mail: denglp@mail.ustc.edu.cn; liuyc@ustc.edu.cn
Search for other works by this author on:
Yi-Can Liu;
1
CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China
, Hefei230026, China
Corresponding authors, e-mail: denglp@mail.ustc.edu.cn; liuyc@ustc.edu.cn
Search for other works by this author on:
Yang Yang;
Yang Yang
1
CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China
, Hefei230026, China
Search for other works by this author on:
Chiara Groppo;
Chiara Groppo
3
Department of Earth Sciences, University of Torino
, Via Valperga Caluso 35, Torino10125, Italy
4
C.N.R. – I.G.G., Section of Torino
, Via Valperga Caluso 35, Torino10125, Italy
Search for other works by this author on:
Franco Rolfo;
Franco Rolfo
3
Department of Earth Sciences, University of Torino
, Via Valperga Caluso 35, Torino10125, Italy
4
C.N.R. – I.G.G., Section of Torino
, Via Valperga Caluso 35, Torino10125, Italy
Search for other works by this author on:
Xiao-Feng Gu
Xiao-Feng Gu
1
CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China
, Hefei230026, China
Search for other works by this author on:
European Journal of Mineralogy (2019) 31 (5-6): 889–903.
Article history
received:
25 Oct 2018
rev-recd:
22 Jul 2019
accepted:
31 Jul 2019
first online:
09 Sep 2019
Citation
Liang-Peng Deng, Yi-Can Liu, Yang Yang, Chiara Groppo, Franco Rolfo, Xiao-Feng Gu; Anatexis of high-T eclogites in the Dabie orogen triggered by exhumation and post-orogenic collapse. European Journal of Mineralogy 2019;; 31 (5-6): 889–903. doi: https://doi.org/10.1127/ejm/2019/0031-2884
Download citation file:
You could not be signed in. Please check your email address / username and password and try again.
Index Terms/Descriptors
- anatexis
- Asia
- asthenosphere
- China
- Cretaceous
- Dabie Mountains
- decompression
- dehydration
- eclogite
- electron probe data
- exhumation
- Far East
- high temperature
- intergrowths
- leucosomes
- Lower Cretaceous
- major elements
- melting
- Mesozoic
- metamorphic rocks
- mica group
- microstructure
- migmatites
- mineral composition
- models
- P-T conditions
- P-T-t paths
- paragenesis
- partial melting
- petrography
- phase equilibria
- phengite
- pressure
- sheet silicates
- silicates
- temperature
- Triassic
- ultrahigh pressure
- Upper Triassic
- upwelling
- whole rock
Latitude & Longitude