滇中易门地区新元古代澄江组凝灰岩锆石U-Pb年龄及其地质意义
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摘要
扬子西缘广泛出露的新元古代澄江组是一套与晋宁运动密切相关的沉积岩夹火山岩系,其形成时限对华南新元古代区域地层格架、地层划分对比及古大陆再造具有重要意义。出露于滇中易门地区的新元古代澄江组底部发育有厚数米的凝灰岩夹层,本次采集凝灰岩进行LA-ICP-MS锆石U-Pb定年研究,结果表明,锆石206Pb/238U年龄加权平均值为812±5. 5Ma(n=17,MSWD=0.46),可以代表滇中澄江组的底界年龄,从而进一步确定澄江组底界年龄为812Ma左右。此外,凝灰岩中捕获的锆石年龄信息指示扬子西缘可能存在2. 5Ga、1. 8～1. 6Ga、1. 5Ga、1. 3Ga及1.0Ga等数期重要的区域构造-热事件。
The widespread Chengjiang Formation strata on the western margin of the Yangtze platform consist dominantly of sedimentary rocks intercalated with the volcanic rock series associated with the Jinning Movement.The timing of the formation of the sedimentary rocks is important to the establishment of the Neoproterozoic regional stratigraphic framework,stratigraphic division and correlation and palaeogeographic reconstruction. In this study,the tuffs with several meters of thickness are found in the basal part of the Neoproterozoic Chengjiang Formation in the Yimen region,central Yunnan. The LA-ICP-MS zircon U-Pb dating of the tuff samples shows that the206 Pb/238 U weighted average age of zircons equals to 812 ± 5. 5 Ma(n = 17 MSWD = 0. 46),and thus the basal boundary of the Chengjiang Formation may be dated at about 812 Ma. The additional age of 723 ± 11. 6 Ma represents the age of the top boundary of the Chengjiang Formation. The above mentioned ages indicate that the volcanic rocks in the Chengjiang Formation may be traced back to the late Neopreterozoic. The age data for the zircons trapped in the tuffs may also imply that several phases of important regional tectonic thermal events once took place at 2. 5 Ga,1. 8 1. 6 Ga and 1. 0 Ga.
The widespread Chengjiang Formation strata on the western margin of the Yangtze platform consist dominantly of sedimentary rocks intercalated with the volcanic rock series associated with the Jinning Movement.The timing of the formation of the sedimentary rocks is important to the establishment of the Neoproterozoic regional stratigraphic framework,stratigraphic division and correlation and palaeogeographic reconstruction. In this study,the tuffs with several meters of thickness are found in the basal part of the Neoproterozoic Chengjiang Formation in the Yimen region,central Yunnan. The LA-ICP-MS zircon U-Pb dating of the tuff samples shows that the206 Pb/238 U weighted average age of zircons equals to 812 ± 5. 5 Ma(n = 17 MSWD = 0. 46),and thus the basal boundary of the Chengjiang Formation may be dated at about 812 Ma. The additional age of 723 ± 11. 6 Ma represents the age of the top boundary of the Chengjiang Formation. The above mentioned ages indicate that the volcanic rocks in the Chengjiang Formation may be traced back to the late Neopreterozoic. The age data for the zircons trapped in the tuffs may also imply that several phases of important regional tectonic thermal events once took place at 2. 5 Ga,1. 8 1. 6 Ga and 1. 0 Ga.
引文
[1]云南省地质矿产局.云南省区域地质志[M].北京:地质出版社,1990. 236-255.
[2]云南省地质矿产局.云南省岩石地层[M].武汉:中国地质大学出版社,1996. 1-100.
[3]《中国地层典》编委会.中国地层典—新元古界[M].北京:地质出版社,1996. 1-117.
[4]刘鸿允.中国震旦系[M].北京:科学出版社,1991. 1-388.
[5]孙家聪.云南罗次澄江组下部火山岩系的发现与震旦系底界年龄的讨论[J].地质科学,1985,(4):334-363.
[6]郝杰,李曰俊,胡文虎.晋宁运动和震旦系有关问题[J].中国区域地质,1992,(2):131-140.
[7]曹仁关,张为鹏,李季.云南东部震旦系的划分与对比[J].地层学杂志,1985,9(3):170-179.
[8]王剑.华南新元古代裂谷盆地演化:兼论与Rodinia解体的关系[M].北京:地质出版社,2000,1-131.
[9]Wang J,Li Z X. History of Neoproterozoic rift basins in South China:implications for Rodinia break-up[J]. Precambrian Research,2003,122:141-158.
[10]崔晓庄,江新胜,王剑,等.滇中新元古代裂谷盆地充填序列及演化模式:对Rodinia超大陆裂解的响应[J].沉积学报,2014,32(3):399-409.
[11]江新胜,王剑,崔晓庄,等.滇中新元古代澄江组锆石SHRIMP U-Pb年代学研究及其地质意义[J].中国科学:地球科学,2012,42(10):1496-1507.
[12]崔晓庄,江新胜,王剑,等.滇中新元古代澄江组层型剖面锆石U-Pb年代学及其地质意义[J].现代地质,2013,27(3):547-556.
[13]崔晓庄,江新胜,王剑,等.扬子西缘澄江组底部玄武岩形成时代新证据及其地质意义[J].岩石矿物学杂志,2015,33(1):1-13.
[14]陆俊泽,江新胜,王剑,等.滇东北巧家地区新元古界澄江组SHRIMP锆石U-Pb年龄及其地质意义[J].矿物学报,2013,33(2):65-71.
[15]Hu Z,Liu Y,Gao S,et al. A“wire”signal smoothing device for laser ablation inductively coupled plasma mass spectrometry analysis[J]. Spectrochimica Acta Part B Atomic Spectro scopy,2012,78(78):50-57.
[16]Ludwing K R. Isoplot 3. 00:A Geochronological Toolkit for Microsoft Excel[M]. Berkelery:Berkeley Geochronology Center,California 39,2003.
[17]王海然,赵红格,乔建新,等.锆石U-Pb同位素测年原理及应用[J].地质与资源,2013,22(3):229-42.
[18]吴元保,郑永飞.锆石成因矿物学研究及其对U-Pb年龄解释的制约[J].科学通报,2004,49(16):1589-1604.
[19]胡世玲,刘鸿允,劳秋元.震旦系地质年代学新研究[J].地质科学,1991,4:325-336.
[20]刘军平,曾文涛,徐云飞,等.滇中易门地区约1. 85Ga凝灰岩的厘定及其地质意义[J].地质通报,2018,37(11):2055-2062.
[21]王子正,郭阳,杨斌,等.扬子克拉通西缘1. 73Ga非造山型花岗斑岩的发现及其地质意义[J].地质学报,2013,87(7):931-942.
[22]郭阳,王生伟,孙晓明,等.云南省武定县迤纳厂铁铜矿区古元古代辉绿岩锆石的U-Pb年龄及其地质意义[J].大地构造与成矿学,2014,38(1):208-215.
[23]刘军平,曾文涛,孙柏东,等.云南峨山地区东川群黑山组流纹质碎斑熔岩锆石U-Pb年龄及其地质意义[J].沉积与特提斯地质,2018,38(3):1 9-25.
[24]孙志明,尹福光,关俊雷,等.云南东川地区昆阳群黑山组凝灰岩锆石SHRIMP U-Pb年龄及其地层学意义[J].地质通报,2009,28(7):898-900.
[25]尹福光,王冬兵,孙志明,等.哥伦比亚超大陆在扬子陆块西缘的探秘[J].沉积与特提斯地质,2012,32(3):31-40.
[26]任光明,庞维华,潘桂棠,等.扬子陆块西缘中元古代菜子园蛇绿混杂岩的厘定及其地质意义[J].地质通报,2017,36(11):2061-2074.
[27]张传恒,高林志,武振杰,等.滇中昆阳群凝灰岩锆石SHRIMP U-Pb年龄华南格林威尔期造山的证据[J].科学通报,2007,52(7):818-824.
[28]刘军平,曾文涛,徐云飞,等.滇中峨山地区中元古界昆阳群黑山头组火山岩锆石U-Pb年龄及其地质意义[J].地质通报,2018,37(11):2063-2070.
[29]周朝宪,魏春生,李朝阳.扬子地块西南缘下震旦系火成岩系研究[J].矿物学报,1998,18(4):401-410.
[30]杨崇辉,耿元生,杜利林,等.扬子地块西缘Grenville期花岗岩的厘定及其地质意义[J].中国地质,2009,36(3):647-657.
[2]云南省地质矿产局.云南省岩石地层[M].武汉:中国地质大学出版社,1996. 1-100.
[3]《中国地层典》编委会.中国地层典—新元古界[M].北京:地质出版社,1996. 1-117.
[4]刘鸿允.中国震旦系[M].北京:科学出版社,1991. 1-388.
[5]孙家聪.云南罗次澄江组下部火山岩系的发现与震旦系底界年龄的讨论[J].地质科学,1985,(4):334-363.
[6]郝杰,李曰俊,胡文虎.晋宁运动和震旦系有关问题[J].中国区域地质,1992,(2):131-140.
[7]曹仁关,张为鹏,李季.云南东部震旦系的划分与对比[J].地层学杂志,1985,9(3):170-179.
[8]王剑.华南新元古代裂谷盆地演化:兼论与Rodinia解体的关系[M].北京:地质出版社,2000,1-131.
[9]Wang J,Li Z X. History of Neoproterozoic rift basins in South China:implications for Rodinia break-up[J]. Precambrian Research,2003,122:141-158.
[10]崔晓庄,江新胜,王剑,等.滇中新元古代裂谷盆地充填序列及演化模式:对Rodinia超大陆裂解的响应[J].沉积学报,2014,32(3):399-409.
[11]江新胜,王剑,崔晓庄,等.滇中新元古代澄江组锆石SHRIMP U-Pb年代学研究及其地质意义[J].中国科学:地球科学,2012,42(10):1496-1507.
[12]崔晓庄,江新胜,王剑,等.滇中新元古代澄江组层型剖面锆石U-Pb年代学及其地质意义[J].现代地质,2013,27(3):547-556.
[13]崔晓庄,江新胜,王剑,等.扬子西缘澄江组底部玄武岩形成时代新证据及其地质意义[J].岩石矿物学杂志,2015,33(1):1-13.
[14]陆俊泽,江新胜,王剑,等.滇东北巧家地区新元古界澄江组SHRIMP锆石U-Pb年龄及其地质意义[J].矿物学报,2013,33(2):65-71.
[15]Hu Z,Liu Y,Gao S,et al. A“wire”signal smoothing device for laser ablation inductively coupled plasma mass spectrometry analysis[J]. Spectrochimica Acta Part B Atomic Spectro scopy,2012,78(78):50-57.
[16]Ludwing K R. Isoplot 3. 00:A Geochronological Toolkit for Microsoft Excel[M]. Berkelery:Berkeley Geochronology Center,California 39,2003.
[17]王海然,赵红格,乔建新,等.锆石U-Pb同位素测年原理及应用[J].地质与资源,2013,22(3):229-42.
[18]吴元保,郑永飞.锆石成因矿物学研究及其对U-Pb年龄解释的制约[J].科学通报,2004,49(16):1589-1604.
[19]胡世玲,刘鸿允,劳秋元.震旦系地质年代学新研究[J].地质科学,1991,4:325-336.
[20]刘军平,曾文涛,徐云飞,等.滇中易门地区约1. 85Ga凝灰岩的厘定及其地质意义[J].地质通报,2018,37(11):2055-2062.
[21]王子正,郭阳,杨斌,等.扬子克拉通西缘1. 73Ga非造山型花岗斑岩的发现及其地质意义[J].地质学报,2013,87(7):931-942.
[22]郭阳,王生伟,孙晓明,等.云南省武定县迤纳厂铁铜矿区古元古代辉绿岩锆石的U-Pb年龄及其地质意义[J].大地构造与成矿学,2014,38(1):208-215.
[23]刘军平,曾文涛,孙柏东,等.云南峨山地区东川群黑山组流纹质碎斑熔岩锆石U-Pb年龄及其地质意义[J].沉积与特提斯地质,2018,38(3):1 9-25.
[24]孙志明,尹福光,关俊雷,等.云南东川地区昆阳群黑山组凝灰岩锆石SHRIMP U-Pb年龄及其地层学意义[J].地质通报,2009,28(7):898-900.
[25]尹福光,王冬兵,孙志明,等.哥伦比亚超大陆在扬子陆块西缘的探秘[J].沉积与特提斯地质,2012,32(3):31-40.
[26]任光明,庞维华,潘桂棠,等.扬子陆块西缘中元古代菜子园蛇绿混杂岩的厘定及其地质意义[J].地质通报,2017,36(11):2061-2074.
[27]张传恒,高林志,武振杰,等.滇中昆阳群凝灰岩锆石SHRIMP U-Pb年龄华南格林威尔期造山的证据[J].科学通报,2007,52(7):818-824.
[28]刘军平,曾文涛,徐云飞,等.滇中峨山地区中元古界昆阳群黑山头组火山岩锆石U-Pb年龄及其地质意义[J].地质通报,2018,37(11):2063-2070.
[29]周朝宪,魏春生,李朝阳.扬子地块西南缘下震旦系火成岩系研究[J].矿物学报,1998,18(4):401-410.
[30]杨崇辉,耿元生,杜利林,等.扬子地块西缘Grenville期花岗岩的厘定及其地质意义[J].中国地质,2009,36(3):647-657.
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