Grossular Exsolution at Pyrope Dislocation: New Evidence for the Ultradeep Origin of Dabie Orogenic Peridotite
Exsolution and dislocation microstructures are an important basis to decipher the conditions of metamorphic deformation and evolution processes of its host minerals and rocks. The grossular-rich exsolution in pyrope-rich garnet grains of Bixiling orogenic crustal cumulative peridotite, Dabie orogen,...
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MDPI AG
2022-05-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/12/5/647 |
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| author | Zhanjun Xie Xiangwen Liu Zhenmin Jin Xiaoqing Liu |
| author_facet | Zhanjun Xie Xiangwen Liu Zhenmin Jin Xiaoqing Liu |
| author_sort | Zhanjun Xie |
| collection | DOAJ |
| description | Exsolution and dislocation microstructures are an important basis to decipher the conditions of metamorphic deformation and evolution processes of its host minerals and rocks. The grossular-rich exsolution in pyrope-rich garnet grains of Bixiling orogenic crustal cumulative peridotite, Dabie orogen, China, was studied by electron backscatter diffraction (EBSD), conventional and high-resolution transmission electron microscopy (TEM/HRTEM) and electron-microprobe analysis (EMPA). Our results indicate that the precursor pyrope-rich host grains had undergone plastic deformation and developed numerous dislocation microstructures before the grossular precipitated. When the pressure and/or temperature decreased during the exhumation of subducted slab, the grossular-rich lamellae exsolved and precipitated at the dislocation structures of host and inherited their shapes. EBSD and TEM analyses show that the crystallographic orientation of exsolution is controlled by, and coherent with, the host grain. These exsolution textures and the chemical composition of precursor garnet correspond to a balance pressure–temperature (<i>P–T</i>) condition of >6 GPa and >850 °C based on the previous thermodynamic models, which indicates that the origin depth of the Bixiling garnet peridotite should be more than 200 km. |
| first_indexed | 2024-03-10T03:04:45Z |
| format | Article |
| id | doaj.art-5468e94f8b534f759efbb87d4e58551a |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-10T03:04:45Z |
| publishDate | 2022-05-01 |
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| series | Crystals |
| spelling | doaj.art-5468e94f8b534f759efbb87d4e58551a2023-11-23T10:34:55ZengMDPI AGCrystals2073-43522022-05-0112564710.3390/cryst12050647Grossular Exsolution at Pyrope Dislocation: New Evidence for the Ultradeep Origin of Dabie Orogenic PeridotiteZhanjun Xie0Xiangwen Liu1Zhenmin Jin2Xiaoqing Liu3Ocean College, Hebei Agricultural University, Qinhuangdao 066000, ChinaState Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, ChinaSchool of Earth Sciences, China University of Geosciences, Wuhan 430074, ChinaCenter for Materials Research and Analysis, Wuhan University of Technology, Wuhan 430074, ChinaExsolution and dislocation microstructures are an important basis to decipher the conditions of metamorphic deformation and evolution processes of its host minerals and rocks. The grossular-rich exsolution in pyrope-rich garnet grains of Bixiling orogenic crustal cumulative peridotite, Dabie orogen, China, was studied by electron backscatter diffraction (EBSD), conventional and high-resolution transmission electron microscopy (TEM/HRTEM) and electron-microprobe analysis (EMPA). Our results indicate that the precursor pyrope-rich host grains had undergone plastic deformation and developed numerous dislocation microstructures before the grossular precipitated. When the pressure and/or temperature decreased during the exhumation of subducted slab, the grossular-rich lamellae exsolved and precipitated at the dislocation structures of host and inherited their shapes. EBSD and TEM analyses show that the crystallographic orientation of exsolution is controlled by, and coherent with, the host grain. These exsolution textures and the chemical composition of precursor garnet correspond to a balance pressure–temperature (<i>P–T</i>) condition of >6 GPa and >850 °C based on the previous thermodynamic models, which indicates that the origin depth of the Bixiling garnet peridotite should be more than 200 km.https://www.mdpi.com/2073-4352/12/5/647garnet exsolutionpyrope–grossular solvusdislocation structureultradeep origin |
| spellingShingle | Zhanjun Xie Xiangwen Liu Zhenmin Jin Xiaoqing Liu Grossular Exsolution at Pyrope Dislocation: New Evidence for the Ultradeep Origin of Dabie Orogenic Peridotite Crystals garnet exsolution pyrope–grossular solvus dislocation structure ultradeep origin |
| title | Grossular Exsolution at Pyrope Dislocation: New Evidence for the Ultradeep Origin of Dabie Orogenic Peridotite |
| title_full | Grossular Exsolution at Pyrope Dislocation: New Evidence for the Ultradeep Origin of Dabie Orogenic Peridotite |
| title_fullStr | Grossular Exsolution at Pyrope Dislocation: New Evidence for the Ultradeep Origin of Dabie Orogenic Peridotite |
| title_full_unstemmed | Grossular Exsolution at Pyrope Dislocation: New Evidence for the Ultradeep Origin of Dabie Orogenic Peridotite |
| title_short | Grossular Exsolution at Pyrope Dislocation: New Evidence for the Ultradeep Origin of Dabie Orogenic Peridotite |
| title_sort | grossular exsolution at pyrope dislocation new evidence for the ultradeep origin of dabie orogenic peridotite |
| topic | garnet exsolution pyrope–grossular solvus dislocation structure ultradeep origin |
| url | https://www.mdpi.com/2073-4352/12/5/647 |
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