| Guandishan Granitoids of the Paleoproterozoic Lüliang Metamorphic Complex in the Trans-North China Orogen: SHRIMP Zircon Ages, Petrogenesis and Tectonic Implications |
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| 引用本文： | LIU Shuwen,LI Qiugen,LIU Chaohui,Lü Yongjun,ZHANG Fan. Guandishan Granitoids of the Paleoproterozoic Lüliang Metamorphic Complex in the Trans-North China Orogen: SHRIMP Zircon Ages, Petrogenesis and Tectonic Implications[J]. 《地质学报》英文版, 2009, 83(3): 580-602. DOI: 10.1111/j.1755-6724.2009.00051.x |
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| 作者姓名： | LIU Shuwen LI Qiugen LIU Chaohui Lü Yongjun ZHANG Fan |
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| 作者单位： | The Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing 100871, China;The Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing 100871, China;The Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing 100871, China;The Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing 100871, China;The Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing 100871, China |
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| 基金项目： | Financial support for this study was provided by the National Natural Science Foundation of China (No.: 40821002, 40872120, 40420120135, 40472096, and 40472118). |
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| 摘 要： | Abstract: The Paleoproterozoic Lüliang Metamorphic Complex (PLMC) is situated in the middle segment of the western margin of the Trans-North China Orogen (TNCO), North China Craton (NCC). As the most important lithological assemblages in the southern part of the PLMC, Guandishan granitoids consist of early gneissic tonalities, granodiorites and gneissic monzogranites, and younger gneissic to massive monzogranites. Petrochemical features reveal that the early gneissic tonalities and granodiorites belong to the medium-K calc-alkaline series; the early gneissic monzogranites are transitional from high-K calc-alkaline to the shoshonite series; the younger gneissic to massive monzogranites belong to the high-k calc-alkaline series, and all rocks are characterized by right-declined REE patterns and negative Nb, Ta, Sr, P, and Ti anomalies in the primitive mantle normalized spidergrams. SHRIMP zircon U–Pb isotopic dating reveals that the early gneissic tonalities and granodiorites formed at ~2.17 Ga, the early gneissic monzogranites at ~2.06 Ga, and the younger gneissic to massive monzogranites at ~1.84 Ga. Sm–Nd isotopic data show that the early gneissic tonalities and granodiorites have εNd(t) values of +0.48 to ?3.19 with Nd-depleted mantle model ages (TDM) of 2.76–2.47 Ga, and early gneissic monzogranites have εNd(t) values of ?0.53 to ?2.51 with TDM of 2.61–2.43 Ga, and the younger gneissic monzogranites have εNd(t) values of ?6.41 to ?2.78 with a TDM of 2.69–2.52 Ga.These geochemical and isotopic data indicate that the early gneissic tonalities, granodiorites, and monzogranites were derived from the partial melting of metamorphosed basaltic and pelitic rocks, respectively, in a continental arc setting. The younger gneissic to massive monzogranites were derived by partial melting of metamorphosed greywackes within the continental crust. Combined with previously regional data, we suggest that the Paleoproterozoic granitoid magmatism in the Guandishan granitoids of the PLMC may provide the best geological signature for the complete spectrum of Paleoproterozoic geodynamic processes in the Trans-North China Orogen from oceanic subduction, through collisional orogenesis, to post-orogenic extension and uplift.
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| 关 键 词： | Guandishan granitoid petrogenesis SHRIMP zircon geochronology geochemistry Nd isotopes Paleoproterozoic Lüliangshan Complex Trans-North China Orogen North China craton. |
| 收稿时间： | 2009-02-04 |
| 修稿时间： | 2009-03-24 |
Guandishan Granitoids of the Paleoproterozoic Lüliang Metamorphic Complex in the Trans‐North China Orogen: SHRIMP Zircon Ages,Petrogenesis and Tectonic Implications |
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| Shuwen LIU,Qiugen LI,Chaohui LIU,Yongjun LÜ,Fan ZHANG. Guandishan Granitoids of the Paleoproterozoic Lüliang Metamorphic Complex in the Trans‐North China Orogen: SHRIMP Zircon Ages,Petrogenesis and Tectonic Implications[J]. Acta Geologica Sinica (English Edition), 2009, 83(3): 580-602. DOI: 10.1111/j.1755-6724.2009.00051.x |
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| Authors: | Shuwen LIU Qiugen LI Chaohui LIU Yongjun LÜ Fan ZHANG |
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| Affiliation: | The Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing 100871, China;The Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing 100871, China;The Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing 100871, China;The Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing 100871, China;The Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing 100871, China |
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| Abstract: | The Paleoproterozoic Lüliang Metamorphic Complex (PLMC) is situated in the middle segment of the western margin of the Trans‐North China Orogen (TNCO), North China Craton (NCC). As the most important lithological assemblages in the southern part of the PLMC, Guandishan granitoids consist of early gneissic tonalities, granodiorites and gneissic monzogranites, and younger gneissic to massive monzogranites. Petrochemical features reveal that the early gneissic tonalities and granodiorites belong to the medium‐K calc‐alkaline series; the early gneissic monzogranites are transitional from high‐K calc‐alkaline to the shoshonite series; the younger gneissic to massive monzogranites belong to the high‐k calc‐alkaline series, and all rocks are characterized by right‐declined REE patterns and negative Nb, Ta, Sr, P, and Ti anomalies in the primitive mantle normalized spidergrams. SHRIMP zircon U–Pb isotopic dating reveals that the early gneissic tonalities and granodiorites formed at ～2.17 Ga, the early gneissic monzogranites at ～2.06 Ga, and the younger gneissic to massive monzogranites at ～1.84 Ga. Sm–Nd isotopic data show that the early gneissic tonalities and granodiorites have ?Nd(t) values of +0.48 to –3.19 with Nd‐depleted mantle model ages (TDM) of 2.76–2.47 Ga, and early gneissic monzogranites have ?Nd(t) values of –0.53 to –2.51 with TDM of 2.61–2.43 Ga, and the younger gneissic monzogranites have ?Nd(t) values of –6.41 to –2.78 with a TDM of 2.69–2.52 Ga. These geochemical and isotopic data indicate that the early gneissic tonalities, granodiorites, and monzogranites were derived from the partial melting of metamorphosed basaltic and pelitic rocks, respectively, in a continental arc setting. The younger gneissic to massive monzogranites were derived by partial melting of metamorphosed greywackes within the continental crust. Combined with previously regional data, we suggest that the Paleoproterozoic granitoid magmatism in the Guandishan granitoids of the PLMC may provide the best geological signature for the complete spectrum of Paleoproterozoic geodynamic processes in the Trans‐North China Orogen from oceanic subduction, through collisional orogenesis, to post‐orogenic extension and uplift. |
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| Keywords: | Guandishan granitoid petrogenesis SHRIMP zircon geochronology geochemistry Nd isotopes Paleoproterozoic Lüliangshan Complex Trans‐North China Orogen North China craton |
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