| Recognition of Early Paleozoic Magmatisms in the Supposed Proterozoic Basements of Zhalantun, Great Xing'an Range, NE China | |
| Alternative Title | Recognition of Early Paleozoic Magmatisms in the Supposed Proterozoic Basements of Zhalantun, Great Xing’an Range, NE China |
| Qin Tao1; Guo Rongrong3; Zang Yanqing2; Qian Cheng2; Wang Yan2; Si Qiuliang2; Sun Wei2; Ma Yongfei2 | |
| 2019 | |
| Source Publication | ACTA GEOLOGICA SINICA-ENGLISH EDITION
 |
| ISSN | 1000-9515 |
| Volume | 93Issue:5Pages:1434-1455 |
| Abstract | The Zhalantun terrane from the Xing'an massif, northeast China, was used to be considered as Proterozoic basements. However, amounts of detrital zircon ages from the meta-sedimentary rocks deny the existence of Precambrian basements recently. Notably, magmatic rocks were barely reported to limit the exact ages of the Zhalantun basements. In this study, we collected rhyolite, gabbro and quartz diorite for zircon in-situ U-Pb isotopic dating, which yield crystallization ages of similar to 505 Ma, similar to 447 Ma and similar to 125 Ma, respectively. Muscovite schist and siltstone define maximum depositional ages of similar to 499 Ma and similar to 489 Ma, respectively. Additionally, these dated supracrustal rocks and plutons also yield ancient detrital/xenocryst zircon ages of similar to 600-1000 Ma, similar to 1600-2220 Ma, similar to 2400 Ma, similar to 2600-2860 Ma. Based on the whole-rock major and trace element compositions, the similar to 505 Ma rhyolites display high SiO2 and alkaline contents, low Fe2O3T, TiO2 and Al2O3, and relatively high MgO and Mg-#, which exhibit calc-alkaline characteristics. These rhyolites yield fractionated REE patterns and negative Nb, Ta, Ti, Sr, P and Eu anomalies and positive Zr anomalies. The geochemistry, petrology and Lu-Hf isotopes imply that rhyolites were derived from the partial melting of continental basalt induced by upwelling of sub-arc mantle magmas, and then experienced fractional crystallization of plagioclase, which points to a continental arc regime. The similar to 447 Ma gabbros exhibit low SiO2 and alkaline contents, high Fe2O3T, TiO2, MgO and Mg-#. They show minor depletions of La and Ce, flat MREE and HREE patterns, and negative Nb, Ta, Zr and Hf anomalies. Both sub-arc mantle and N-MORB-like mantle were involved in the formation of the gabbros, indicative of a probable back-arc basin tectonic setting. Given that, the previously believed Proterozoic supracrustal rocks and several plutons from the Zhalantun Precambrian basements were proved to be Paleozoic to Mesozoic rocks, among which these Paleozoic magmatic rocks were generally related to subduction regime. So far, none Proterozoic rocks have been identified from the Zhalantun Precambrian basement, though some similar to 600-3210 Ma ancient detrital/xenocryst zircons were reported. Combined with ancient zircon ages and newly reported similar to 2.5 Ga and similar to 1.8 Ga granites from the south of the Zhalantun, therefore, the Precambrian rocks probably once exposed in the Zhalantun while they were re-worked and consumed during later long tectonic evolutionary history, resulting in absence of Precambrian rocks in the Zhalantun. |
| Other Abstract | The Zhalantun terrane from the Xing’an massif, northeast China, was used to be considered as Proterozoic basements. However, amounts of detrital zircon ages from the meta-sedimentary rocks deny the existence of Precambrian basements recently. Notably, magmatic rocks were barely reported to limit the exact ages of the Zhalantun basements. In this study, we collected rhyolite, gabbro and quartz diorite for zircon in-situ U-Pb isotopic dating, which yield crystallization ages of ~505 Ma, ~447 Ma and ~125 Ma, respectively. Muscovite schist and siltstone define maximum depositional ages of ~499 Ma and ~489 Ma, respectively. Additionally, these dated supracrustal rocks and plutons also yield ancient detrital/xenocryst zircon ages of ~600–1000 Ma, ~1600–2220 Ma, ~2400 Ma, ~2600–2860 Ma. Based on the whole-rock major and trace element compositions, the ~505 Ma rhyolites display high SiO_2 and alkaline contents, low Fe_2O_3T, TiO_2 and Al_2O_3, and relatively high MgO and Mg#, which exhibit calc-alkaline characteristics. These rhyolites yield fractionated REE patterns and negative Nb, Ta, Ti, Sr, P and Eu anomalies and positive Zr anomalies. The geochemistry, petrology and Lu-Hf isotopes imply that rhyolites were derived from the partial melting of continental basalt induced by upwelling of sub-arc mantle magmas, and then experienced fractional crystallization of plagioclase, which points to a continental arc regime. The ~447 Ma gabbros exhibit low SiO_2 and alkaline contents, high Fe_2O_3T, TiO_2, MgO and Mg#. They show minor depletions of La and Ce, flat MREE and HREE patterns, and negative Nb, Ta, Zr and Hf anomalies. Both sub-arc mantle and N-MORB-like mantle were involved in the formation of the gabbros, indicative of a probable back-arc basin tectonic setting. Given that, the previously believed Proterozoic supracrustal rocks and several plutons from the Zhalantun Precambrian basements were proved to be Paleozoic to Mesozoic rocks, among which these Paleozoic magmatic rocks were generally related to subduction regime. So far, none Proterozoic rocks have been identified from the Zhalantun Precambrian basement, though some ~600–3210 Ma ancient detrital/xenocryst zircons were reported. Combined with ancient zircon ages and newly reported ~2.5 Ga and ~1.8 Ga granites from the south of the Zhalantun, therefore, the Precambrian rocks probably once exposed in the Zhalantun while they were re-worked and consumed during later long tectonic evolutionary history, resulting in absence of Precambrian rocks in the Zhalantun. |
| Keyword | ASIAN OROGENIC BELT ZIRCON U-PB MESOZOIC VOLCANIC-ROCKS I-TYPE GRANITES LU-HF ISOTOPES NEOARCHEAN SUBDUCTION EASTERN MARGIN CRUSTAL GROWTH JURASSIC GRANITOIDS TRIASSIC VOLCANISM early Paleozoic magmatism Xinghuadukou Group Jiageda Formation Zhalantun terrane Great Xing'an Range Central Asian Orogenic Belt |
| Indexed By | CSCD |
| Language | 英语 |
| Funding Project | [China Geological Survey Project] ; [Fundamental Research Funds for the Central Universities] |
| CSCD ID | CSCD:6591837 |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/152401 |
| Collection | 中国科学院金属研究所 |
| Affiliation | 1.吉林大学 2.中国科学院金属研究所 3.东北大学 |
| Recommended Citation GB/T 7714 | Qin Tao,Guo Rongrong,Zang Yanqing,et al. Recognition of Early Paleozoic Magmatisms in the Supposed Proterozoic Basements of Zhalantun, Great Xing'an Range, NE China[J]. ACTA GEOLOGICA SINICA-ENGLISH EDITION,2019,93(5):1434-1455. |
| APA | Qin Tao.,Guo Rongrong.,Zang Yanqing.,Qian Cheng.,Wang Yan.,...&Ma Yongfei.(2019).Recognition of Early Paleozoic Magmatisms in the Supposed Proterozoic Basements of Zhalantun, Great Xing'an Range, NE China.ACTA GEOLOGICA SINICA-ENGLISH EDITION,93(5),1434-1455. |
| MLA | Qin Tao,et al."Recognition of Early Paleozoic Magmatisms in the Supposed Proterozoic Basements of Zhalantun, Great Xing'an Range, NE China".ACTA GEOLOGICA SINICA-ENGLISH EDITION 93.5(2019):1434-1455. |
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