Unconformity in the Lower Triassic of Micangshan Area, northern Sichuan Province: Its discovery and significance
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摘要: 前人认为四川北部米仓山地区下三叠统内部各组地层之间是整合接触,然而通过构造和沉积学的研究发现下三叠统内部(奥伦尼阶)存在一个区域不整合面。在沉积上表现为环米仓山地区广泛发育的陆相和海相碎屑岩,与下伏地层呈不整合接触。地震剖面上表现为不整合面上下的变形特征不一致、不整合面下部地层被削截、古构造的存在等等,通过对古褶皱和古断裂的平面投影,发现古构造走向为东-西向,与勉略构造带走向一致。综合区域大地构造历史,笔者认为在早三叠世奥伦尼期(约249.7~245.0Ma)南秦岭造山带和上扬子地块就已经发生碰撞,碰撞引起了米仓山地区强烈的构造变形,形成这一区域不整合面。该碰撞时间不一定是南秦岭造山带和上扬子地块在此处的初始碰撞时间。Abstract: No unconformity has been reported within the Lower Triassic of the Micangshan area, but recently we have found a regional unconformity whose age is Olenekian (ca. 249.7~245.0Ma). This unconformity is characterized by a layer of continental or marine clastic rocks overlying the old strata. In the seismic profiles, this unconformity could be easily recognized because of the remarkable difference of the deformation pattern between above and below it, top-truncated formations and paleo-structures below it. The strikes of these paleo-structures are E-W oriented, consistent with that of Mianlue suture northward. According to the regional tectonic history, we attribute this tectonic event as the result of the early collision of the Upper Yangtze Block and South Qinling Orogen, but it may not stand for the onset time of the collision.
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Key words:
- Qinling /
- Micangshan /
- Early Triassic /
- Tongjiezi Formation /
- Upper Yangtze /
- Collision
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[1] Bian QT,Luo XQ,Li DH,Zhao DS,Chen HH,Xu GZ,Chang CF and Gao TL.2001. Geochemistry and formation environment of the Buqingshan ophiolite complex,Qinghai Province,China.Acta Geologica Sinica,75(1):45-55(in Chinese with English abstract)
[2] Bureau of Geology and Mineral Resources of Sichuan Province(BGMRSP).1991. Regional Geology of Siehuan Province.Beijing:Geological Publishing House,183-184,207-208(in Chinese)
[3] Chen L,Sun Y,Liu XM and Pei XZ.2000. Geochemistry of Derni ophiolite and its tectonic significance.Acta Petrologica Sinica,16(1):106-110(in Chinese with English abstract)
[4] Chen L,Sun Y,Pei XZ,Gao M,Feng T and Zhang ZQ.2001.40Ar-39Ar age of the Demi ophiolite:Evidence for the existence and extension of the paleo-Tethyan ocean in the northernmost Qingzang Plateau.Chinese Science Bulletin,46(5):424-426(in Chinese)
[5] Dong YP,Zhang GW,Lai SC,Zhou DW and Zhu BQ.1999. Determination of the Huashan ophiolitic mélange,Suizhou and its tectonic significance.Science in China(Series D),29(3):222-231(in Chinese)
[6] Drafting Group for the Bulletin of Petroleum Geology of Sichuan Province(DGBPGSP).1989. Petroleum Geology of China:Sichuan Province.Beijing:Petroleum Industry Press,31(in Chinese)
[7] Gu XD.1997. Strata of Sichuan Province.Wuhan:China University of Geosciences Publishing House,153(in Chinese)
[8] Han YJ and Ding YL.2002. Prospects on hydrocarbon potential of the frontal areas of the Longmenshan,Micangshan and Dabashan.Natural Gas Exploration and Development,25(1):19-23(in Chinese)
[9] Hu JM,Cui JT,Meng QR and Zhao CY.2004. The U-Pb age of zircons separated from the Zhashui granite in Qinling Orogen and its significance.Geological Review,50(3):323-329(in Chinese with English abstract)
[10] Jin WJ,Zhang Q,He DF and Jia XQ.2005. SHRIMP dating of adakites in western Qinling and their implications.Acta Petrologica Sinica,21(3):959-966(in Chinese with English abstract)
[11] Lai SC,Zhang GW and Pei XZ.2002. Geochemistry of the Pipasi ophiolite in the Mianlue suture zone,South Qinling,and its tectonic significance.Geological Bulletin of China,21(8):465-470(in Chinese with English abstract)
[12] Lai SC,Zhang GW,Pei XZ and Yang HF.2003a.Geochemistry and tectonic significance of the ophiolites and OIB volcanic rocks in the Kangxian-Pipasi-Nanping mélange.Science in China(Series D),33(1):10-19(in Chinese)
[13] Lai SC,Zhang GW,Dong YP,Pei XZ and Chen L.2003b.Lithology and spatio-temporal distribution of the ophiolites and related volcanic rocks in the Mianlue tectonic belt of Qinling-Dabie orogenic belt.Science in China(Series D),33(12):1174-1183(in Chinese)
[14] Li JL,Sun S,Hao J,Chen HH,Hou QL,Xiao WJ and Wu JM.1999. Time limit of collision event of collision orogens.Acta Petrologica Sinica,15(2):315-320(in Chinese with English abstract)
[15] Li M,Zhang CL,Yuan KZ and Yan YX.2004. Geochemical characteristics of Miba intrusion in the South Qinling Belt and its geological significance.Journal of Northwest University(Natural Science Edition),34(3):325-330(in Chinese with English abstract)
[16] Li SG,Sun WD,Zhang GW,Chen JY and Yang YC.1996. Geochronology and geochemistry of the Heigouxia metavolcanics in the Mianlue suture,South Qinling.Science in China(Series D),26(3):223-230(in Chinese)
[17] Li SG,Hou ZH,Yang YC,Sun WD,Zhang GW and Li QL.2003. Geochemical characteristics and formation time of the Sanchazi magmatic arc in the Mianlue suture,South Qinling.Science in China(Series D),33(12):1163-1173(in Chinese)
[18] Liu FL and Xu ZQ.2004. Fluid inclusion in the coesite-hearing zircons in the UHP rocks from South Sulu belt.Chinese Science Bulletin,49(2):18-189(in Chinese)
[19] Liu FL,Xu ZQ,Liou JG and Song B.2004a.SHRIMP U-Pb ages of ultrahigh-pressure and retrograde metamorphism of gneisses,south-western Sulu terrane,eastern China.Journal of Metamorphic Geology,22:315-326
[20] Liu FL,Xu ZQ and Xue HM.2004b.Tracing the protolith,UHP metamorphism,and exhumation ages of orthogneiss from the SW Sulu terrane(eastern China):SHRIMP U-Pb dating of mineral inclusion-bearing zircons.Lithos,78:411-429
[21] Liu FL,Gerdes A,Liou JG,Xue HM and Liang FH.2006. SHRIMP U-Pb zircon dating from Sulu-Dabie dolomitic marble,South China:Constraints on prograde,ultrahigh-pressuro and retrograde metamorphic ages.Journal of Metamorphic Geology,24:569-589
[22] Liu FL,Gerdes A,Zeng LS and Xue HM.2008. SHRIMP U-Pb dating,trace element and Lu-Hf isotope system of coesite-bearing zircon from amphibolite in SW Sulu UHP terrane,eastern China.Geochim.Cosmochim.Acta,72:2973-3000
[23] Liu SF,Zhang GW,Cheng SY and Yao AP.1999. Evolution of flexural basins and process of collision orogeny in East Qinling-Dabie Shan and its adjacent regions.Scientia Goelogica Sinica,34(3):336-346(in Chinese with English abstract)
[24] Liu SF,Steel R and Zhang GW.2005. Mesozoic sedimentary basin development and tectonic implication,northern Yangtze Block,eastern China:Record of continent-continent collision.Journal of Asian Earth Sciences,(25):9-27
[25] Lu XX,Wei XD,Xiao QH,Zhang ZQ,Li HM and Wang W.1999. Geochronological studies of rapakivi granites in Qinling and its geological implications.Geological Journal of China Universities,5(4):372-377(in Chinese with English abstract)
[26] Mattauer M,Matte P,Malavieille J,Tapponnier P,Maluski H,Xu ZQ,Lu YL and Tang YQ.1985. Tectonics of the Qinling Belt:Build-up and evolution of eastern Asia.Nature,317(6037):496-500
[27] Meng QR and Zhang GW.1999. Timing of collision of the North and South China blocks:Controversy and reconciliation.Geology,27(2):123-126
[28] Meng QR,Wang EQ and Hu JM.2005. Mesozoic sedimentary evolution of the northwest Sichuan basin:Implication for continued clockwise rotation of the South China block.GSA Bulletin,117(3-4):396-410
[29] No.2 Regional Geological Survey Group of Sichuan Geological Bureau(NRGSGSGB).1966. Reports ofRegional Geological Survey-Nanjiang.Beijing:Geological Publishing House,17-26(in Chinese)
[30] No.2 Regional Geological Survey Group of Sichuan Geological Bureau(NRGSGSGB).1967. Reports of Regional Geological Survey-Guangyuan.Beijing:Geological Publishing House,9-13(in Chinese)
[31] No.2 Regional Geological Survey Group of Sichuan Geological Bureau(NRGSGSGB).1970. Reports of Regional Geological Survey-Zhenba.Beijing:Geological Publishing House,14-18(in Chinese)
[32] Qin JF,Lai SC and Li YF.2007. Genesis of the Indosinian Guangtoushan adakitic biotite plagiogranite in the Mianxian-Lueyang(Mianlue)suture,South Qinling,China,and its tectonic implications.Geological Bulletin of China,26(4):466-471(in Chinese with English abstract)
[33] Qin JF,Lai SC,Wang J and Li YF.2008. Zircon LA-ICP MS U-Pb age,Sr-Nd-Pb isotopic compositions and geochemistry of the Triassic post-collisional Wulong adakitic granodiofite in the South Qinling,Central China,and its petrogenesis.Acta Geologica Sinica,82(2):425-437
[34] Qinling Regional Geological Survey Group(QRGSG).1960. Reports of Regional Geological Survey-Lueyang.Beijing:Geological Publishing House,39-45(in Chinese)
[35] Regional Geological Survey Group of Shaanxi Geological Bureau(RGSGSGB).1965. Reports of Regional Geological Survey-Hanzhong.Beijing:Geological Publishing House,15-17(in Chinese)
[36] Sun WD,Li SG,Chen YD and Li YJ.2000. Zircon U-Pb dating of granitoids from South Qinling,Central China and their geological significance.Geochimica,29(3):209-216(in Chinese with English abstract)
[37] Wan YS,Li RW,Wilde SA,Liu DY,Chen ZY,Yan L,Song TR and Yin XY.2005. UHP metamorphism and exhumation of the Dabie Orogen,China:Evidence from SHRIMP dating of zircon and monazite from a UHP granitic gneiss cobble from the Hefei Basin.Geochim.Cosmochim.Acta,69:4333-4348
[38] Wang F,Lu XX,Lo CH,Wu FY,He HY,Yang LK and Zhu RX.2007. Post-collisional,potassic monzonite-minette complex(Shahewan)in the Qinling Mountains(central China):40Ar/39Ar thermochronology,petrogenesis,and implications for the dynamic setting of the Qinling orogen.Journal of Asian Earth Sciences,31(2):153-166
[39] Wang J,Jin Q,Lai SC,Qin JF and Li X.2008a.Research of geochemistry and petrogenesis of the Wulong granites in the Fuping region,South Qinling Mountains.Journal of Mineralogy and Petrology,28(1):79-87(in Chinese with English abstract)
[40] Wang J,Li X,Lai SC and Qin JF.2008h.Petrogenesis of the Early Triassic Xichahe and Wulong plutons in the South Qinling Mountains and their tectonic significance.Geology in China,35(2):207-216(in Chinese with English abstract)
[41] Wang XX,Wang T,Jahn BM,Hu NG and Chen W.2007. Tectonic significance of Late Triassic post-collisional lamprophyre dykes from the Qinling Mountains(China).Geological Magazine,144(5):837-848
[42] Wang YG,Wen YC,Zhang F,Yang Y and Zhang J.1998. Distribution law of the organic reefs in Changxing Formation of Upper Permian in east Sichuan.Natural Gas Industry,18(6):10-15(in Chinese with English abstract)
[43] Wang YG,Wen YC,Hong HT,Xia ML and Song SJ.2006. Dalong Formation found in Kaijiang-Liangping oceanic trough in the Siehuan Basin.Natural Gas Industry,26(9):32-36(in Chinese with English abstract)
[44] Wei GQ,Chen GS,Yang W,Yang Y,Hu YL,Zhang L,Wn SX,Jin H and Shen YH.2004. Sedimentary system of platformal trough of Feixianguan Formation of Lower Triassic in northern Sichuan Basin and its evolution.Acta Sedimentologica Sinica,22(2):254-260(in Chinese with English abstract)
[45] Yan QR,Wang ZQ,Yan Z,Xiang ZJ,Chen JL and Wang T.2007. SHRIMP analyses for ophiolitic-mafic blocks in the Kangxian-Mianxian section of the Mianxian-Lueyang mélange:Their geological implications.Geological Review,53(6):755-764(in Chinese with English abstract)
[46] Yang JS,Wooden JL,Wu CL,Liu FL,Xu ZQ,Shi RD,Katayama I,Liou JG and Maruyama S.2003. SHRIMP U-Pb dating of coesitebearing zircon from the ultrahigh-pressure metamorphic rocks,Sulu terrane,east China.Journal of Metamorphic Geology,21:551-560
[47] Yan YX and Zhang CL.2005. Geochemical characteristic and tectonic setting of Zhangjiaba and Xinyuan plutons in South Qinling.Geological Journal of China Universities,11(3):425-433(in Chinese with English abstract)
[48] Yin A and Nie SY.1993. An indentation model for the North and South China collision and the development of the Tan-Lu and Honam fault systems,Eastern Asia.Tectonics,12(4):801-813
[49] Zhang CL,Luo JL,Li M and Wang Y.2002. Geochemical characteristics and geological significance of Xiba granite,porphyry and porphyrite in East Qinling.Journal of Northwest University(Natural Science Edition),32(4):384-388(in Chinese with English abstract)
[50] Zhang CL,Zhang GW,Yan YX and Wang Y.2005. Origin and dynamic significance of Guangtoushan granitic plutons to the north of Mianlue zone in southern Qinling.Acta Petrologica Sinica,21(3):711-720(in Chinese with English abstract)
[51] Zhang GW,Dang YP,Lai SC,Guo LA,Meng QR,Liu SF,Cheng SY,Yao AP,Zhang ZQ,Pei XZ and Li SZ.2003. Mianlue tectonic belt and Mianlue suture on the southern margin of Qinling-Dabie orogenic belt.Science in China(Series D),33(12):1121-1135(in Chinese)
[52] Zhang J,Chen YJ,Shu GM,Zhang FX and Li C.2002. Mineral composition of the Qinlingliang granitic pluton in the southwestern Shaanxi Province and discussions of related issues.Science in China(Series D),32(2):113-120(in Chinese)
[53] 边千韬,罗小全,李涤徽,赵大升,陈海泓,徐贵忠,常承法,高廷林.2001.青海省阿尼玛卿带布青山蛇绿混杂岩的地球化学性质及形态环境.地质学报,75(1):45-55
[54] 陈亮,孙勇,柳小明,裴先治.2000.青海省德尔尼蛇绿岩的地球化学特征及其大地构造意义.岩石学报,16(1):106-110
[55] 陈亮,孙勇,裴先治,高明,冯涛,张宗清.2001.德尔尼蛇绿岩40Ar-39Ar年龄:青藏最北端古特提斯洋盆存在和延展的证据.科学通报,46(5):424-426
[56] 董云鹏,张国伟,赖少聪,周鼎武,朱炳泉.1999.随州花山蛇绿构造混杂岩的厘定及其大地构造意义,中国科学(D辑),29(3):222-231
[57] 辜学达.1997.四川省岩石地层.武汉:中国地质大学出版社,153
[58] 韩应钧.丁玉兰.2002.龙门山、米仓山、大巴山及前其缘带石油天然气远景预测.天然气勘探与开发,25(1):19-23
[59] 胡健民,崔建堂,孟庆任,赵长缨.2004.秦岭柞水岩体锆石U-Pb年龄及其地质意义.地质论评,50(3):323-329
[60] 金维浚,张旗,何登发,贾秀勤.2005.西秦岭埃达克岩的SHRIMP定年及其构造意义.岩石学报.21(3):959-966
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