Protolith ages and timing of peak and retrograde metamorphism of the high-pressure granulites in the Shandong Peninsula, eastern North China Craton
High-pressure (HP) granulites widely occur as enclaves within tonalite-trondhjemite-granodiorite (TTG) gneisses of the Early Precambrian metamorphic basement in the Shandong Peninsula, southeast part of the North China Craton (NCC). Based on cathodoluminescence (CL), laser Raman spectroscopy and in-...
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Elsevier
2012-11-01
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| Series: | Geoscience Frontiers |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674987112000564 |
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| author | Pinghua Liu Fulai Liu Hong Yang Fang Wang Jianhui Liu |
| author_facet | Pinghua Liu Fulai Liu Hong Yang Fang Wang Jianhui Liu |
| author_sort | Pinghua Liu |
| collection | DOAJ |
| description | High-pressure (HP) granulites widely occur as enclaves within tonalite-trondhjemite-granodiorite (TTG) gneisses of the Early Precambrian metamorphic basement in the Shandong Peninsula, southeast part of the North China Craton (NCC). Based on cathodoluminescence (CL), laser Raman spectroscopy and in-situ U-Pb dating, we characterize the zircons from the HP granulites and group them into three main types: inherited (magmatic) zircon, HP metamorphic zircon and retrograde zircon. The inherited zircons with clear or weakly defined magmatic zoning contain inclusions of apatites, and 207Pb/206Pb ages of 2915–2890 Ma and 2763–2510 Ma, correlating with two magmatic events in the Archaean basement. The homogeneous HP metamorphic zircons contain index minerals of high-pressure metamorphism including garnet, clinopyroxene, plagioclase, quartz, rutile and apatite, and yield 207Pb/206Pb ages between 1900 and 1850 Ma, marking the timing of peak HP granulite facies metamorphism. The retrograde zircons contain inclusions of orthopyroxene, plagioclase, quartz, apatite and amphibole, and yield the youngest 207Pb/206Pb ages of 1840–1820 Ma among the three groups, which we correlate to the medium to low-pressure granulite facies retrograde metamorphism. The data presented in this study suggest subduction of Meso- and Neoarchean magmatic protoliths to lower crust depths where they were subjected to HP granulite facies metamorphism during Palaeoproterozoic (1900–1850 Ma). Subsequently, the HP granulites were exhumated to upper crust levels, and were overprinted by medium to low-pressure granulite and amphibolite facies retrograde event at ca. 1840–820 Ma. |
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| language | English |
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| spelling | doaj.art-e847f051ebbd46e282b6d1d0b4a2e7e02023-08-02T00:11:10ZengElsevierGeoscience Frontiers1674-98712012-11-013692394310.1016/j.gsf.2012.04.001Protolith ages and timing of peak and retrograde metamorphism of the high-pressure granulites in the Shandong Peninsula, eastern North China CratonPinghua LiuFulai LiuHong YangFang WangJianhui LiuHigh-pressure (HP) granulites widely occur as enclaves within tonalite-trondhjemite-granodiorite (TTG) gneisses of the Early Precambrian metamorphic basement in the Shandong Peninsula, southeast part of the North China Craton (NCC). Based on cathodoluminescence (CL), laser Raman spectroscopy and in-situ U-Pb dating, we characterize the zircons from the HP granulites and group them into three main types: inherited (magmatic) zircon, HP metamorphic zircon and retrograde zircon. The inherited zircons with clear or weakly defined magmatic zoning contain inclusions of apatites, and 207Pb/206Pb ages of 2915–2890 Ma and 2763–2510 Ma, correlating with two magmatic events in the Archaean basement. The homogeneous HP metamorphic zircons contain index minerals of high-pressure metamorphism including garnet, clinopyroxene, plagioclase, quartz, rutile and apatite, and yield 207Pb/206Pb ages between 1900 and 1850 Ma, marking the timing of peak HP granulite facies metamorphism. The retrograde zircons contain inclusions of orthopyroxene, plagioclase, quartz, apatite and amphibole, and yield the youngest 207Pb/206Pb ages of 1840–1820 Ma among the three groups, which we correlate to the medium to low-pressure granulite facies retrograde metamorphism. The data presented in this study suggest subduction of Meso- and Neoarchean magmatic protoliths to lower crust depths where they were subjected to HP granulite facies metamorphism during Palaeoproterozoic (1900–1850 Ma). Subsequently, the HP granulites were exhumated to upper crust levels, and were overprinted by medium to low-pressure granulite and amphibolite facies retrograde event at ca. 1840–820 Ma.http://www.sciencedirect.com/science/article/pii/S1674987112000564High-pressure granuliteZirconMineral inclusionsU-Pb geochronologyShandong PeninsulaNorth China Craton |
| spellingShingle | Pinghua Liu Fulai Liu Hong Yang Fang Wang Jianhui Liu Protolith ages and timing of peak and retrograde metamorphism of the high-pressure granulites in the Shandong Peninsula, eastern North China Craton Geoscience Frontiers High-pressure granulite Zircon Mineral inclusions U-Pb geochronology Shandong Peninsula North China Craton |
| title | Protolith ages and timing of peak and retrograde metamorphism of the high-pressure granulites in the Shandong Peninsula, eastern North China Craton |
| title_full | Protolith ages and timing of peak and retrograde metamorphism of the high-pressure granulites in the Shandong Peninsula, eastern North China Craton |
| title_fullStr | Protolith ages and timing of peak and retrograde metamorphism of the high-pressure granulites in the Shandong Peninsula, eastern North China Craton |
| title_full_unstemmed | Protolith ages and timing of peak and retrograde metamorphism of the high-pressure granulites in the Shandong Peninsula, eastern North China Craton |
| title_short | Protolith ages and timing of peak and retrograde metamorphism of the high-pressure granulites in the Shandong Peninsula, eastern North China Craton |
| title_sort | protolith ages and timing of peak and retrograde metamorphism of the high pressure granulites in the shandong peninsula eastern north china craton |
| topic | High-pressure granulite Zircon Mineral inclusions U-Pb geochronology Shandong Peninsula North China Craton |
| url | http://www.sciencedirect.com/science/article/pii/S1674987112000564 |
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