Early Paleozoic Accretionary Orogenesis on Western Margin of Baoshan Block
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摘要: 在保山地块西缘泸水-潞西构造带内, 出露一套构造混杂岩.主体为强变形的震旦系-古生界蒲满哨群、公养河群浅变质碎屑岩夹碳酸盐岩及火山岩等复理石浊积岩系等构成, 另有硅质岩、杂砂岩、灰岩、砾岩、玄武岩及花岗岩等弱变形的构造块体.岩石时代从震旦纪至古生代, 跨度大, 高度混杂, 并有从东向西变新的逐势, 表现为后退式增生.构造样式早期为同斜倒转冲断作用的叠瓦构造, 后期表现为近N-S向剪切.玄武安山岩、流纹岩类具弧火山岩特征, 而玄武岩类则为板内火山岩, 2种火山岩分别对应岛弧与弧后拉张洋盆产物.寒武纪、奥陶纪侵位的花岗岩也分为东西2个带, 西晚东早, 代表了保山陆块西缘岩浆弧的一部分.这样就记录了洋壳俯冲消亡、增生楔形成过程的沉积、火山-岩浆、变质和构造变形的地质事件群, 也记录了保山地块西缘早古生代增生造山形成过程的地质事件, 并证明了泸水-潞西构造带在震旦纪-古生代存在一洋盆.Abstract: On the western margin of the Baoshan block, a set of tectonic mélange can be seen along the western Lushui-Luxi tectonic zone. It is characterized by matrices consisting of strongly deformed and low-grade metamorphic clastic rocks bearing graptolite of Sinian-Paleozoic Pumanshao Group and Gongyanghe Group and volcanic flysch turbidite, and structural lens consisting of siliceous, graywacke, part limestone, conglomerate, basalt and granite. The ages of these rocks range from Sinian to Paleozoic and get younger from east to west, which shows the characters of retrogressive accretion. In the early stage, the structural styles are characterized by imbricate structures formed by thrust faults and homoclinal-overturned folds, and nearly N-S-trending shear in the late stage. The characteristics of basalt-andesite and rhylite are of arc volcanic rocks, and the basalt shows characteristics of continental intraplate volcanic rocks. Both of the two types of volcanic rocks maybe account for the tectonic setting of island arc and back-arc extension. Cambrian and Ordovician granite can be divided into the western belt and eastern belt, and the ages of the latter are earlier than that of the former. Those granites are part of magmatic arc of the western margin of the Baoshan block. Therefore, this tectonic mélange records the geological events such as extinction to the subduction of the oceanic crust and magmatic sedimentation-volcanic-magmatic-tectonic events during the formation process of accretionary wedge, and also records the information of the Early Paleozoic accretionary orogenesis on the western margin of the Baoshan block. Meanwhile, it suggests the existence of an ocean basin during Sinian-Paleozoic in the Lushui-Luxi tectonic zone.
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Key words:
- Baoshan block /
- Early Paleozoic /
- accretionary orogenesis /
- petrology /
- sedimentology /
- tectonics
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图 1 保山地块西缘大地构造位置简图
Ⅰ.华南板块；Ⅱ.三江造山系；Ⅱ1.哀牢山结合带；Ⅱ2.墨江-绿春陆缘弧；Ⅱ3.昌都-思茅地块；Ⅱ4.云县-景谷火山弧；Ⅱ5.澜沧江结合带；Ⅱ6.临沧-勐海岩浆弧；Ⅲ.昌宁-孟连结合带；Ⅳ.冈底斯-腾冲陆缘造山系；Ⅳ1.保山-镇康地块；Ⅳ2.潞西-三台山结合带；Ⅳ3.冈底斯-腾冲岩浆弧；Ⅳ4.腾冲-梁河岩浆弧
Fig. 1. Geological geotectonic map of the western margin of the Baoshan block
图 2 保山地块西缘地质简图(云南省地质调查院，云南1∶25万腾冲县幅、潞西市幅区域地质调查报告，2008)
1.第四系；2.新近系；3.古近系；4.侏罗系-白垩系；5.三叠系(?)；6.奥陶系-志留系；7.上古生界；8.下古生界；9.蒲满哨群；10.公养河群；11.新元古界；12.古元古界；13.古近纪花岗岩；14.晚白垩世花岗岩；15.早白垩世花岗岩；16.早白垩世花岗闪长岩；17.侏罗纪花岗岩；18.三叠纪花岗岩；19.三叠纪超基性岩；20.奥陶纪花岗岩；21.中元古代花岗岩；22.分区断裂及编号；23.一般断裂及编号；24.糜棱岩带；25.超糜凌岩带；26.背斜轴线；27.向斜轴线；28.角度不整合界线；29.火山喷发不整合界线；30.构造层及岩体界线；31.居民点；32.山峰；33.水系
Fig. 2. Geological map of the western margin of the Baoshan block
图 3 保山地块西缘火山岩稀土元素配分图(a)和微量元素比值蛛网图(b) (据云南省地质调查院，云南1∶25万腾冲县幅、潞西市幅区域地质调查报告，2008)
Fig. 3. Chondrite-normalized REE patterens diagrams (a) and primitive mantle-normalized trace elements spider diagrams (b) of the volcanic rocks in western Baoshan block
图 4 泸水-潞西火山岩带Ti-Zr图解(a)和Ti/100-Zr-3Y图解(云南省地质调查院，云南1∶25万腾冲县幅、潞西市幅区域地质调查报告，2008)
Fig. 4. Discrimination Ti-Zr diagrams (a) and discrimination Ti/100-Zr-3Y diagrams (b) of tectonic environment of Lushui-Nujiang volcanic zone
图 5 保山地块西缘奥陶纪花岗岩的稀土元素配分图(a)和微量元素比值蛛网图(b) (云南省地质调查院，云南1∶25万腾冲县幅、潞西市幅区域地质调查报告，2008)
Fig. 5. Chondrite-normalized REE patterens diagrams (a) and primitive mantle-normalized trace elements spider diagrams (b) of the Ordovician granite in western Baoshan block
图 6 保山地块西缘奥陶纪花岗岩的R1-R2图解(a)和Rb/30-Hf-3Ta图解(b) (云南省地质调查院，云南1∶25万腾冲县幅、潞西市幅区域地质调查报告，2008)
1.地幔分异的花岗岩；2.碰撞前花岗岩；3.碰撞后隆起的花岗岩；4.造山晚期-晚造山期花岗岩；5.非造山区花岗岩；6.同碰撞花岗岩；7.造山期后的花岗岩
Fig. 6. Discrimination R1-R2 diagrams (a) and discrimination Rb/30-Hf-3Ta diagrams (b) of the Ordovician granite in western Baoshan block
图 7 保山地块西缘奥陶纪花岗岩微量元素原始地幔标准化蜘蛛图解(a)和稀土元素球粒陨石标准化图解(b) (熊昌利等，2012)
Fig. 7. Primitive mantle-normalized trace elements spider diagrams (a) and chondrite-normalized REE patterens diagrams (b) of the Ordovician granite in western Baoshan block
图 8 三台山超基性岩铅同位素组成图解(中国地质调查局成都地质调查中心，云南1∶5万梁河幅、江东幅、帕底幅区域地质调查报告，2011)
Fig. 8. Pb-isotope compositions of ultra-basic rocks from Santaishan area
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Cawood, P.A., Kroener, A., Windley, B.F., 2003. Accretionary Orogens: Definition, Character, Significance. EGS-AGU-EUG Joint Assembly, Abstracts from the Meeting Held in Nice, France. Chu, Z.Y., Wang, W., Chen, F.K., et al., 2009. Os-Nd-Pb-Sr Isotopic Compositions of the Santaishan Ultramafic Rock in Western Yunnan and Its Geological Significances. Acta Petrologica Sinica, 25(12): 3221-3228(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-YSXB200912012.htm Condie, K.C., 2005. An Overview of Accretionary Orogens. Geological Society of America Abstracts with Programs, 37(7): 493. http://gsa.confex.com/gsa/2005AM/finalprogram/abstract_89112.htm Dong, M.L., Dong, G.C., Mo, X.X., et al., 2012. Geochronology and Geochemistry of the Early Palaeozoic Granitoids in Baoshan Block, Western Yunnan and Their Implications. Acta Petrologica Sinica, 28(5): 1453-1464(in Chinese with English abstract). Jahn, B.M., 2007. Accretionary Orogens in Japan—What was Accreted in the Accretionary Complexes since the Late Paleozoic. The Third International Workshop and Field Excursion for IGCP-480, Beijing. Li, C.N., 1992. Trace Elements Petrology of Igneous Rocks. China University of Geosciences Press, Wuhan (in Chinese). Li, J.L., 2004. Basic Characteristics of Accretion-Type Orogens. Geological Bulletin of China, 23: 947-951(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-ZQYD2004Z2017.htm Li, X.Z., Liu, W.J., Wang, Y.Z., et al., 1999. The Tectonic Evolution and Metallogenesis in the Tethys of the Nujiang-Lancangjiang-Jinshajiang Area, Southwestern China. Geological Publishing House, Beijing(in Chinese). Liu, B.P., Feng, Q.L., Chonglakmani, C., et al., 2002. Framework of Paleotethyan Archipelago Ocean of WesternYunnan and Its Elongation towards North and South. Earth Science Frontiers, 9(3): 161-171(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DXQY200203027.htm Liu, Q.S., Ye, P.S., Wu, Z.H., 2012. SHRIMP Zircon U-Pb Dating and Petrogeochemistry of Ordovician Granite Bodies in the Southern Segment of Gaoligong Mountain, Western Yunnan Province. Geological Bulletin of China, 31(2): 250-257(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-ZQYD2012Z1006.htm Pan, G.T., Chen, Z.L., Li, X.Z., et al., 1997. Geological Structure Formation and Evolution of East Tethys. Geological Publishing House, Beijing(in Chinese). Sengör, A.M.C., 2006. Turkic Type Orogeny and a Short History of the Last 600 Million Years. Asia Oceania Geosciences Society, Singapore. Sengör, A.M.C., Natal'In, B.A., 1996. Turkic-Type Orogeny and Its Role in the Making of the Continental Crust. Annual Review of Earth and Planetary Sciences, 24(1): 263-337. doi: 10.1146/annurev.earth.24.1.263 Sengör, A.M.C., Natal'in, B.A., Burtman, V.S., 1993. Evolution of the Altaid Tectonic College and Paleozoic Crustal Growth in Eurasia. Nature, 364: 299-307. doi: 10.1038/364299a0 Tan, M., Zhan, W.D., 1990. Preliminary Research of Ophiolite Belt in South Langcangjiang Belt, Western Yunnan. Exploration of Geosciences, 3: 91-96(in Chinese with English abstract). Windley, B.F., 1992. Proterozoic Collisional and Accretionary Orogens. Developments in Precambrian Geology, 10: 419-446. http://www.onacademic.com/detail/journal_1000038410395210_05f5.html Xiong, C.L., Jia, X.C., Yang, X.J., et al., 2012. LA-ICP-MS Zircon U-Pb Dating of Ordovician Mengmao Monzogranite in Longling Area of Western Yunnan Province and Its Tectonic Setting. Geological Bulletin of China, 31(2-3): 175-286(in Chinese with English abstract). Yang, X.J., Jia, X.C., Xiong, C.L., et al., 2012. LA-ICP-MS Zircon U-Pb Age of Metamorphic Basic Volcanic Rock in Gongyanghe Group of Southern Gaoligong Mountain, Western Yunnan Province, and Its Geological Significance. Geological Bulletin of China, 31(2): 264-276(in Chinese with English abstract). Yuan, S.H., Pan, G.T., Wang, L.Q., et al., 2009. Accretionary Orogenesis in the Active Continental Margins. Earth Science Frontiers, 16(3): 31-48(in Chinese with English abstract). doi: 10.1016/S1872-5791(08)60095-0 Zhang, Q., Zhou, D.J., Zhao, D.S., et al., 1996. Wilson Cycle of the Paleo-Tethyan Orogenic Belt in Western Yunnan: Record of Magmatism and Discussion on Mantle Processes. Acta Petrologica Sinica, 12(1): 17-28(in Chinese with English abstract). Zhong, D.L., 1998. The Paleo-Tethys Orogenic Belt of WesternYunnan and Sichuan. Science Press, Beijing (in Chinese). 储著银, 王伟, 陈福坤, 等, 2009. 云南潞西三台山超镁铁岩体Os-Nd-Pb-Sr同位素特征及地质意义. 岩石学报, 25(12): 3221-3228. https://www.cnki.com.cn/Article/CJFDTOTAL-YSXB200912012.htm 董美玲, 董国臣, 莫宣学, 等, 2012. 滇西保山地块早古生代花岗岩类的年代学、地球化学及意义. 岩石学报, 28(5): 1453-1464. https://www.cnki.com.cn/Article/CJFDTOTAL-YSXB201205011.htm 李昌年, 1992. 火成岩微量元素岩石学. 武汉: 中国地质大学出版社. 李继亮, 2004. 增生型造山带的基本特征. 地质通报, 23(9-10): 947-951. https://www.cnki.com.cn/Article/CJFDTOTAL-ZQYD2004Z2017.htm 李兴振, 刘文均, 王义昭, 等, 1999. 西南三江地区特提斯构造演化与成矿. 北京: 地质出版社. 刘本培, 冯庆来, Chonglakmani, C., 等, 2002. 滇西古特提斯多岛洋的结构及其南北延伸. 地学前缘, 9(3): 161-171. doi: 10.3321/j.issn:1005-2321.2002.03.020 刘琦胜, 叶培盛, 吴中海, 2012. 滇西高黎贡山南段奥陶纪花岗岩SHRIMP锆石U-Pb测年和地球化学特征. 地质通报, 31(2-3): 250-257. https://www.cnki.com.cn/Article/CJFDTOTAL-ZQYD2012Z1006.htm 潘桂棠, 陈智良, 李兴振, 等, 1997. 东特提斯地质构造形成演化. 北京: 地质出版社. 谭敏, 詹五第, 1990. 云南怒江带三台山蛇绿岩带的初证. 地学探索, 3: 91-96. 熊昌利, 贾小川, 杨学俊, 等, 2012. 滇西龙陵地区勐冒奥陶纪二长花岗岩LA-ICP-MS锆石U-Pb定年及其构造环境. 地质通报, 31(2-3): 175-286. https://www.cnki.com.cn/Article/CJFDTOTAL-ZQYD2012Z1009.htm 杨学俊, 贾小川, 熊昌利, 等, 2012. 滇西高黎贡山南段公养河群变质基性火山岩LA-ICP-MS锆石U-Pb年龄及其地质意义. 地质通报, 31(2-3): 264-276. https://www.cnki.com.cn/Article/CJFDTOTAL-ZQYD2012Z1008.htm 袁四化, 潘桂棠, 王立全, 等, 2009. 大陆边缘增生造山作用. 地学前缘, 16(3): 31-48. doi: 10.3321/j.issn:1005-2321.2009.03.002 张旗, 周德进, 赵大升, 等, 1996. 滇西古特提斯造山带的威尔逊旋回: 岩浆活动记录和深部过程讨论. 岩石学报, 12(1): 17-28. doi: 10.3321/j.issn:1000-0569.1996.01.002 钟大赉, 1998. 滇川西部古特提斯构造带. 北京: 科学出版社. -
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