| 摘要: |
| （目的）为制约南段组沉积时代和构造环境，阐明临沧地块演化特征。（方法）本文进行南段组碎屑锆石U-Pb年代学研究，并结合以往研究成果。（结果）南段组具统计意义最年轻组碎屑锆石年龄为512±13Ma、509.6±5.9Ma，具泛非期（530~680Ma）、晚格林威尔期（900~980Ma）、早格林威尔期（1100~1300Ma）三期年龄组段特点。（结论）认为南段组最大沉积下限为寒武纪，中上部上限为石炭纪，物源来自于东冈瓦纳超大陆内部至少3条造山带，主要为南极Pinjarra造山带、西澳Albany-Fraser造山带、东澳Paterson-Peterman造山带，具亲冈瓦纳大陆性质，在古生代冈瓦纳大陆重建中，位于澳大利亚地块北缘，是一个从西澳大利亚地块往东澳大利亚地块往北往东迁移从被动大陆边缘到活动大陆边缘转换的演化过程，早期沉积环境为滨浅海或三角洲，后期为弧前增生楔沉积环境。 |
| 关键词: 碎屑锆石 临沧地块 南段组 滇西 岗瓦纳大陆重建 |
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| U-Pb geochronology of the detrital zircons from the southern segment of the Changning Menglian suture zone in western Yunnan: Constraints on sedimentary age and tectonic environment |
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huangxiaoming1,2,3, mouchuanlong2,3,4
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1.Chengdu University of Technology;2.Chengdu Institute of Geology&3.Mineral Resources，China Geological Survey;4.Key Laboratory of sedimentary basins and petroleum resources, Ministry of natural resources
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| Abstract: |
| （Objective）In order to restrict the sedimentary age and tectonic environment of the Nanduan Formaiton, Clarify the evolution characteristics of Lincang block.（Method）The U-Pb geochronology of detrital zircon in the Nanduan Formaiton is studied in this paper, Combined with previous research results.（Result）The youngest zircons from the Nanduan Formation are 512 ± 13 Ma and 509.6 ± 5.9 Ma, It is characterized by three age groups: Pan African period (530 ~ 680 Ma), late Greenville period (900 ~ 980 Ma) and early Greenville period (1100 ~ 1300 Ma).（Conclusion）It is considered that the maximum sedimentary lower limit of the Nanduan Formaiton is Cambrian,The upper limit of the middle and upper part is Carboniferous, The provenance comes from at least three orogenic belts in the East Gondwana supercontinent, It is mainly the Pinjarra orogenic belt in Antarctica, the Albany Fraser orogenic belt in Western Australia and the Paterson Peterman orogenic belt in eastern Australia, It has Gondwana affinity, In the reconstruction of Gondwana continent in Paleozoic, It is located on the northern edge of the Australian plot, It is an evolutionary process from the Western Australia block to the eastern Australia block, moving north to East, and transforming from the passive continental margin to the active continental margin, The early sedimentary environment was coastal shallow sea or delta, The later stage is forearc accretionary wedge sedimentary environment. |
| Key words: Detrital zircon Lincang Block Nanduan Formation Western Yunnan The rebuilding of Gondwana |